
# Changelog

All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).

NOTE: As semantic versioning states all 0.y.z releases can contain breaking changes in API (flags, grpc API, any backward compatibility)

We use _breaking :warning:_ to mark changes that are not backward compatible (relates only to v0.y.z releases.)

## [v0.20.1](https://github.com/thanos-io/thanos/releases/tag/v0.20.1) - 2021.04.30

### Fixed

- [#4123](https://github.com/thanos-io/thanos/pull/4123) Query: match external labels for exemplars API.

## [v0.20.0](https://github.com/thanos-io/thanos/releases/tag/v0.20.0) - 2021.04.28

### Added

- [#4029](https://github.com/thanos-io/thanos/pull/4029) Mixin: Remove dependency on the rule dashboard when generating the compact dashboard
- [#4019](https://github.com/thanos-io/thanos/pull/4019) Query: Adds query range histogram.
- [#3846](https://github.com/thanos-io/thanos/pull/3846) Query: Added federated exemplars API support.
- [#3350](https://github.com/thanos-io/thanos/pull/3350) Query/Sidecar: Added targets API support. You can now configure you Querier to fetch Prometheus targets from leaf Prometheus-es!
- [#3977](https://github.com/thanos-io/thanos/pull/3903) Expose exemplars for `http_request_duration_seconds` histogram if tracing is enabled.
- [#3903](https://github.com/thanos-io/thanos/pull/3903) Store: Returning custom grpc code when reaching series/chunk limits.
- [#3919](https://github.com/thanos-io/thanos/pull/3919) Allow to disable automatically setting CORS headers using `--web.disable-cors` flag in each component that exposes an API.
- [#3840](https://github.com/thanos-io/thanos/pull/3840) Tools: Added a flag to support rewrite Prometheus TSDB blocks.
- [#3920](https://github.com/thanos-io/thanos/pull/3920) Query Frontend: Support `max_item_size` in Query frontend Memcached cache.
- [#4078](https://github.com/thanos-io/thanos/pull/4078) receive: Improved efficiency of multitsdb appends, upgraded Prometheus deps.

### Fixed

- [#3204](https://github.com/thanos-io/thanos/pull/3204) Mixin: Use sidecar's metric timestamp for healthcheck.
- [#3922](https://github.com/thanos-io/thanos/pull/3922) *: Fix panic in http logging middleware.
- [#3960](https://github.com/thanos-io/thanos/pull/3960) Ruler: Fix deduplication of equal alerts with different labels.
- [#3937](https://github.com/thanos-io/thanos/pull/3937) Store: Fix race condition in chunk pool.
- [#4017](https://github.com/thanos-io/thanos/pull/4017) Query Frontend: fix downsampling iterator returning duplicate samples.
- [#4041](https://github.com/thanos-io/thanos/pull/4041) Logging: fix the HTTP logger.

### Changed

- [#3929](https://github.com/thanos-io/thanos/pull/3929) Store: Adds the name of the instantiated memcached client to log info.
- [#3827](https://github.com/thanos-io/thanos/pull/3827) Upgrade Go version to 1.16
- [#3948](https://github.com/thanos-io/thanos/pull/3948) Receiver: Adjust `http_request_duration_seconds` buckets for low latency requests.
- [#3856](https://github.com/thanos-io/thanos/pull/3856) Mixin: _breaking :warning:_ Introduce flexible multi-cluster/namespace mode for alerts and dashboards. Removes jobPrefix config option. Removes `namespace` by default.
- [#3937](https://github.com/thanos-io/thanos/pull/3937) Store: Reduce memory usage for range queries.
- [#4045](https://github.com/thanos-io/thanos/pull/4045) UI: Enable Targets page in Querier UI.
- [#4062](https://github.com/thanos-io/thanos/pull/4062) Flags: Sort flags alphabetically.
- [#4081](https://github.com/thanos-io/thanos/pull/4081) UI: Make the ReactUI the default one.
- [#4085](https://github.com/thanos-io/thanos/pull/4085) Receive: Improved Performance for err path.
- [#4094](https://github.com/thanos-io/thanos/pull/4094) *: Upgrade Prometheus & Alertmanager.

## [v0.20.0](https://github.com/thanos-io/thanos/releases/tag/v0.20.0) - 2021.03.31

- [#3700](https://github.com/thanos-io/thanos/pull/3700) Compact/Web: Make old bucket viewer UI work with vanilla Prometheus blocks.
- [#3657](https://github.com/thanos-io/thanos/pull/3657) *: It's now possible to configure HTTP transport options for S3 client.
- [#3752](https://github.com/thanos-io/thanos/pull/3752) Compact/Store: Added `--block-meta-fetch-concurrency` allowing to configure number of go routines for block metadata synchronization.
- [#3723](https://github.com/thanos-io/thanos/pull/3723) Query Frontend: Added `--query-range.request-downsampled` flag enabling additional queries for downsampled data in case of empty or incomplete response to range request.
- [#3579](https://github.com/thanos-io/thanos/pull/3579) Cache: Added inmemory cache for caching bucket.
- [#3792](https://github.com/thanos-io/thanos/pull/3792) Receiver: Added `--tsdb.allow-overlapping-blocks` flag to allow overlapping tsdb blocks and enable vertical compaction.
- [#3740](https://github.com/thanos-io/thanos/pull/3740) Query: Added `--query.default-step` flag to set default step. Useful when your tenant scrape interval is stable and far from default UI's 1s.
- [#3686](https://github.com/thanos-io/thanos/pull/3686) Query/Sidecar: Added metric metadata API support. You can now configure you Querier to fetch Prometheus metrics metadata from leaf Prometheus-es!
- [#3031](https://github.com/thanos-io/thanos/pull/3031) Compact/Sidecar/Receive/Rule: Added `--hash-func`. If some function has been specified, writers calculate hashes using that function of each file in a block before uploading them. If those hashes exist in the `meta.json` file then Compact does not download the files if they already exist on disk and with the same hash. This also means that the data directory passed to Thanos Compact is only *cleared once at boot* or *if everything succeeds*. So, if you, for example, use persistent volumes on k8s and your Thanos Compact crashes or fails to make an iteration properly then the last downloaded files are not wiped from the disk. The directories that were created the last time are only wiped again after a successful iteration or if the previously picked up blocks have disappeared.

### Fixed

- [#3705](https://github.com/thanos-io/thanos/pull/3705) Store: Fix race condition leading to failing queries or possibly incorrect query results.
- [#3661](https://github.com/thanos-io/thanos/pull/3661) Compact: Deletion-mark.json is deleted as the last one, which could in theory lead to potential store gateway load or query error for such in-deletion block.
- [#3760](https://github.com/thanos-io/thanos/pull/3760) Store: Fix panic caused by a race condition happening on concurrent index-header reader usage and unload, when `--store.enable-index-header-lazy-reader` is enabled.
- [#3759](https://github.com/thanos-io/thanos/pull/3759) Store: Fix panic caused by a race condition happening on concurrent index-header lazy load and unload, when `--store.enable-index-header-lazy-reader` is enabled.
- [#3773](https://github.com/thanos-io/thanos/pull/3773) Compact: Fixed compaction planner size check, making sure we don't create too large blocks.
- [#3814](https://github.com/thanos-io/thanos/pull/3814) Store: Decreased memory utilisation while fetching block's chunks.
- [#3815](https://github.com/thanos-io/thanos/pull/3815) Receive: Improve handling of empty time series from clients
- [#3795](https://github.com/thanos-io/thanos/pull/3795) s3: A truncated "get object" response is reported as error.
- [#3899](https://github.com/thanos-io/thanos/pull/3899) Receive: Correct the inference of client gRPC configuration.
- [#3943](https://github.com/thanos-io/thanos/pull/3943) Receive: Fixed memory regression introduced in v0.17.0.
- [#3960](https://github.com/thanos-io/thanos/pull/3960) Query: Fixed deduplication of equal alerts with different labels.

### Changed

- [#3804](https://github.com/thanos-io/thanos/pull/3804) Ruler, Receive, Querier: Updated Prometheus dependency. TSDB characteristics might have changed.

## [v0.18.0](https://github.com/thanos-io/thanos/releases/tag/v0.18.0) - 2021.01.27

### Added

- [#3380](https://github.com/thanos-io/thanos/pull/3380) Mixin: Add block deletion panels for compactor dashboards.
- [#3568](https://github.com/thanos-io/thanos/pull/3568) Store: Optimized inject label stage of index lookup.
- [#3566](https://github.com/thanos-io/thanos/pull/3566) StoreAPI: Support label matchers in labels API.
- [#3531](https://github.com/thanos-io/thanos/pull/3531) Store: Optimized common cases for time selecting smaller amount of series by avoiding looking up symbols.
- [#3469](https://github.com/thanos-io/thanos/pull/3469) StoreAPI: Added `hints` field to `LabelNamesRequest` and `LabelValuesRequest`. Hints are an opaque data structure that can be used to carry additional information from the store and its content is implementation-specific.
- [#3421](https://github.com/thanos-io/thanos/pull/3421) Tools: Added `thanos tools bucket rewrite` command allowing to delete series from given block.
- [#3509](https://github.com/thanos-io/thanos/pull/3509) Store: Added a CLI flag to limit the number of series that are touched.
- [#3444](https://github.com/thanos-io/thanos/pull/3444) Query Frontend: Make POST request to downstream URL for labels and series API endpoints.
- [#3388](https://github.com/thanos-io/thanos/pull/3388) Tools: Bucket replicator now can specify block IDs to copy.
- [#3385](https://github.com/thanos-io/thanos/pull/3385) Tools: Bucket prints extra statistics for block index with debug log-level.
- [#3121](https://github.com/thanos-io/thanos/pull/3121) Receive: Added `--receive.hashrings` alternative to `receive.hashrings-file` flag (lower priority). The flag expects the literal hashring configuration in JSON format.

### Fixed

- [#3567](https://github.com/thanos-io/thanos/pull/3567) Mixin: Reintroduce `thanos_objstore_bucket_operation_failures_total` alert.
- [#3527](https://github.com/thanos-io/thanos/pull/3527) Query Frontend: Fix query_range behavior when start/end times are the same
- [#3560](https://github.com/thanos-io/thanos/pull/3560) Query Frontend: Allow separate label cache
- [#3672](https://github.com/thanos-io/thanos/pull/3672) Rule: Prevent crashing due to `no such host error` when using `dnssrv+` or `dnssrvnoa+`.
- [#3461](https://github.com/thanos-io/thanos/pull/3461) Compact, Shipper, Store: Fixed panic when no external labels are set in block metadata.

### Changed

- [#3496](https://github.com/thanos-io/thanos/pull/3496) S3: Respect SignatureV2 flag for all credential providers.
- [#2732](https://github.com/thanos-io/thanos/pull/2732) Swift: Switched to a new library [ncw/swift](https://github.com/ncw/swift) providing large objects support.
   By default, segments will be uploaded to the same container directory `segments/` if the file is bigger than `1GB`.
   To change the defaults see [the docs](./docs/storage.md#openstack-swift).
- [#3626](https://github.com/thanos-io/thanos/pull/3626) Shipper: Failed upload of `meta.json` file doesn't cause block cleanup anymore. This has a potential to generate corrupted blocks under specific conditions. Partial block is left in bucket for later cleanup.

## [v0.17.2](https://github.com/thanos-io/thanos/releases/tag/v0.17.2) - 2020.12.07

### Fixed

- [#3532](https://github.com/thanos-io/thanos/pull/3532) compact: do not cleanup blocks on boot. Reverts the behavior change introduced in [#3115](https://github.com/thanos-io/thanos/pull/3115) as in some very bad cases the boot of Thanos Compact took a very long time since there were a lot of blocks-to-be-cleaned.
- [#3520](https://github.com/thanos-io/thanos/pull/3520) Fix index out of bound bug when comparing ZLabelSets.

## [v0.17.1](https://github.com/thanos-io/thanos/releases/tag/v0.17.1) - 2020.11.24

### Fixed

- [#3480](https://github.com/thanos-io/thanos/pull/3480) Query Frontend: Fixed regression.
- [#3734](https://github.com/thanos-io/thanos/pull/3734) pkg/rules/proxy: fix hotlooping when receiving client errors

### Changed

- [#3498](https://github.com/thanos-io/thanos/pull/3498) Enabled debug.SetPanicOnFault(true) which allow us to recover on queries causing SEG FAULTs (e.g unmmaped memory access).

## [v0.17.0](https://github.com/thanos-io/thanos/releases/tag/v0.17.0) - 2020.11.18

### Added

- [#3259](https://github.com/thanos-io/thanos/pull/3259) Thanos BlockViewer: Added a button in the blockviewer that allows users to download the metadata of a block.
- [#3261](https://github.com/thanos-io/thanos/pull/3261) Thanos Store: Use segment files specified in meta.json file, if present. If not present, Store does the LIST operation as before.
- [#3276](https://github.com/thanos-io/thanos/pull/3276) Query Frontend: Support query splitting and retry for label names, label values and series requests.
- [#3315](https://github.com/thanos-io/thanos/pull/3315) Query Frontend: Support results caching for label names, label values and series requests.
- [#3346](https://github.com/thanos-io/thanos/pull/3346) Ruler UI: Fix a bug preventing the /rules endpoint from loading.
- [#3115](https://github.com/thanos-io/thanos/pull/3115) compact: now deletes partially uploaded and blocks with deletion marks concurrently. It does that at the beginning and then every `--compact.cleanup-interval` time period. By default it is 5 minutes.
- [#3312](https://github.com/thanos-io/thanos/pull/3312) s3: add list_objects_version config option for compatibility.
- [#3356](https://github.com/thanos-io/thanos/pull/3356) Query Frontend: Add a flag to disable step alignment middleware for query range.
- [#3378](https://github.com/thanos-io/thanos/pull/3378) Ruler: added the ability to send queries via the HTTP method POST. Helps when alerting/recording rules are extra long because it encodes the actual parameters inside of the body instead of the URI. Thanos Ruler now uses POST by default unless `--query.http-method` is set `GET`.
- [#3381](https://github.com/thanos-io/thanos/pull/3381) Querier UI: Add ability to enable or disable metric autocomplete functionality.
- [#2979](https://github.com/thanos-io/thanos/pull/2979) Replicator: Add the ability to replicate blocks within a time frame by passing --min-time and --max-time
- [#3398](https://github.com/thanos-io/thanos/pull/3398) Query Frontend: Add default config for query frontend memcached config.
- [#3277](https://github.com/thanos-io/thanos/pull/3277) Thanos Query: Introduce dynamic lookback interval. This allows queries with large step to make use of downsampled data.
- [#3409](https://github.com/thanos-io/thanos/pull/3409) Compactor: Added support for no-compact-mark.json which excludes the block from compaction.
- [#3245](https://github.com/thanos-io/thanos/pull/3245) Query Frontend: Add `query-frontend.org-id-header` flag to specify HTTP header(s) to populate slow query log (e.g. X-Grafana-User).
- [#3431](https://github.com/thanos-io/thanos/pull/3431) Store: Added experimental support to lazy load index-headers at query time. When enabled via `--store.enable-index-header-lazy-reader` flag, the store-gateway will load into memory an index-header only once it's required at query time. Index-header will be automatically released after `--store.index-header-lazy-reader-idle-timeout` of inactivity.
  - This, generally, reduces baseline memory usage of store when inactive, as well as a total number of mapped files (which is limited to 64k in some systems.
- [#3437](https://github.com/thanos-io/thanos/pull/3437) StoreAPI: Added `hints` field to `LabelNamesResponse` and `LabelValuesResponse`. Hints in an opaque data structure that can be used to carry additional information from the store and its content is implementation specific.
   * This, generally, reduces baseline memory usage of store when inactive, as well as a total number of mapped files (which is limited to 64k in some systems.
- [#3415](https://github.com/thanos-io/thanos/pull/3415) Tools: Added `thanos tools bucket mark` command that allows to mark given block for deletion or for no-compact

### Fixed

- [#3257](https://github.com/thanos-io/thanos/pull/3257) Ruler: Prevent Ruler from crashing when using default DNS to lookup hosts that results in "No such hosts" errors.
- [#3331](https://github.com/thanos-io/thanos/pull/3331) Disable Azure blob exception logging
- [#3341](https://github.com/thanos-io/thanos/pull/3341) Disable Azure blob syslog exception logging
- [#3414](https://github.com/thanos-io/thanos/pull/3414) Set CORS for Query Frontend
- [#3437](https://github.com/thanos-io/thanos/pull/3437) Add external labels to Labels APIs.

### Changed

- [#3452](https://github.com/thanos-io/thanos/pull/3452) Store: Index cache posting compression is now enabled by default. Removed `experimental.enable-index-cache-postings-compression` flag.
- [#3410](https://github.com/thanos-io/thanos/pull/3410) Compactor: Changed metric `thanos_compactor_blocks_marked_for_deletion_total` to `thanos_compactor_blocks_marked_total` with `marker` label.
  Compactor will now automatically disable compaction for blocks with large index that would output blocks after compaction larger than specified value (by default: 64GB). This automatically
  handles the Promethus [format limit](https://github.com/thanos-io/thanos/issues/1424).
- [#2906](https://github.com/thanos-io/thanos/pull/2906) Tools: Refactor Bucket replicate execution. Removed all `thanos_replicate_origin_.*` metrics.
  - `thanos_replicate_origin_meta_loads_total` can be replaced by `blocks_meta_synced{state="loaded"}`.
  - `thanos_replicate_origin_partial_meta_reads_total` can be replaced by `blocks_meta_synced{state="failed"}`.
- [#3309](https://github.com/thanos-io/thanos/pull/3309) Compact: _breaking :warning:_ Rename metrics to match naming convention. This includes metrics starting with `thanos_compactor` to `thanos_compact`, `thanos_querier` to `thanos_query` and `thanos_ruler` to `thanos_rule`.

## [v0.16.0](https://github.com/thanos-io/thanos/releases/tag/v0.16.0) - 2020.10.26

Highlights:

- New Thanos component, [Query Frontend](https://thanos.io/tip/components/query-frontend.md/) has more options and supports shared cache (currently: Memcached).
- Added debug mode in Thanos UI that allows to filter Stores to query from by their IPs from Store page (!). This helps enormously in e.g debugging the slowest store etc. All raw Thanos API allows passing
  `storeMatch[]` arguments with `__address__` matchers.
- Improved debuggability on all Thanos components by exposing [off-CPU profiles thanks to fgprof endpoint](https://github.com/felixge/fgprof).
- Significantly improved sidecar latency and CPU usage for metrics fetches.

### Fixed

- [#3234](https://github.com/thanos-io/thanos/pull/3234) UI: Fix assets not loading when `--web.prefix-header` is used.
- [#3184](https://github.com/thanos-io/thanos/pull/3184) Compactor: Fixed support for `web.external-prefix` for Compactor UI.

### Added

- [#3114](https://github.com/thanos-io/thanos/pull/3114) Query Frontend: Added support for Memcached cache.
    - **breaking** Renamed flag `log_queries_longer_than` to `log-queries-longer-than`.
- [#3166](https://github.com/thanos-io/thanos/pull/3166) UIs: Added UI for passing a `storeMatch[]` parameter to queries.
- [#3181](https://github.com/thanos-io/thanos/pull/3181) Logging: Added debug level logging for responses between 300-399
- [#3133](https://github.com/thanos-io/thanos/pull/3133) Query: Allowed passing a `storeMatch[]` to Labels APIs; Time range metadata based store filtering is supported on Labels APIs.
- [#3146](https://github.com/thanos-io/thanos/pull/3146) Sidecar: Significantly improved sidecar latency (reduced ~2x). Added `thanos_sidecar_prometheus_store_received_frames` histogram metric.
- [#3147](https://github.com/thanos-io/thanos/pull/3147) Querier: Added `query.metadata.default-time-range` flag to specify the default metadata time range duration for retrieving labels through Labels and Series API when the range parameters are not specified. The zero value means range covers the time since the beginning.
- [#3207](https://github.com/thanos-io/thanos/pull/3207) Query Frontend: Added `cache-compression-type` flag to use compression in the query frontend cache.
- [#3122](https://github.com/thanos-io/thanos/pull/3122) \*: All Thanos components have now `/debug/fgprof` endpoint on HTTP port allowing to get [off-CPU profiles as well](https://github.com/felixge/fgprof).
- [#3109](https://github.com/thanos-io/thanos/pull/3109) Query Frontend: Added support for `Cache-Control` HTTP response header which controls caching behaviour. So far `no-store` value is supported and it makes the response skip cache.
- [#3092](https://github.com/thanos-io/thanos/pull/3092) Tools: Added `tools bucket cleanup` CLI tool that deletes all blocks marked to be deleted.

### Changed

- [#3136](https://github.com/thanos-io/thanos/pull/3136) Sidecar: **breaking** Added metric `thanos_sidecar_reloader_config_apply_operations_total` and rename metric `thanos_sidecar_reloader_config_apply_errors_total` to `thanos_sidecar_reloader_config_apply_operations_failed_total`.
- [#3154](https://github.com/thanos-io/thanos/pull/3154) Querier: **breaking** Added metric `thanos_query_gate_queries_max`. Remove metric `thanos_query_concurrent_selects_gate_queries_in_flight`.
- [#3154](https://github.com/thanos-io/thanos/pull/3154) Store: **breaking** Renamed metric `thanos_bucket_store_queries_concurrent_max` to `thanos_bucket_store_series_gate_queries_max`.
- [#3179](https://github.com/thanos-io/thanos/pull/3179) Store: context.Canceled will not increase `thanos_objstore_bucket_operation_failures_total`.
- [#3136](https://github.com/thanos-io/thanos/pull/3136) Sidecar: Improved detection of directory changes for Prometheus config.
  - **breaking** Added metric `thanos_sidecar_reloader_config_apply_operations_total` and rename metric `thanos_sidecar_reloader_config_apply_errors_total` to `thanos_sidecar_reloader_config_apply_operations_failed_total`.
- [#3022](https://github.com/thanos-io/thanos/pull/3022) \*: Thanos images are now build with Go 1.15.
- [#3205](https://github.com/thanos-io/thanos/pull/3205) \*: Updated TSDB to ~2.21

## [v0.15.0](https://github.com/thanos-io/thanos/releases/v0.15.0) - 2020.09.07

Highlights:

- Added new Thanos component: [Query Frontend](https://thanos.io/v0.15/components/query-frontend/) responsible for response caching,
  query scheduling and parallelization (based on Cortex Query Frontend).
- Added various new, improved UIs to Thanos based on React: Querier BuildInfo & Flags, Ruler UI, BlockViewer.
- Optimized Sidecar, Store, Receive, Ruler data retrieval with new TSDB ChunkIterator (capping chunks to 120 samples), which fixed various leaks.
- Fixed sample limit on Store Gateway.
- Added S3 Server Side Encryption options.
- Tons of other important fixes!

### Fixed

- [#2665](https://github.com/thanos-io/thanos/pull/2665) Swift: Fix issue with missing Content-Type HTTP headers.
- [#2800](https://github.com/thanos-io/thanos/pull/2800) Query: Fix handling of `--web.external-prefix` and `--web.route-prefix`.
- [#2834](https://github.com/thanos-io/thanos/pull/2834) Query: Fix rendered JSON state value for rules and alerts should be in lowercase.
- [#2866](https://github.com/thanos-io/thanos/pull/2866) Receive, Querier: Fixed leaks on receive and querier Store API Series, which were leaking on errors.
- [#2937](https://github.com/thanos-io/thanos/pull/2937) Receive: Fixing auto-configuration of `--receive.local-endpoint`.
- [#2895](https://github.com/thanos-io/thanos/pull/2895) Compact: Fix increment of `thanos_compact_downsample_total` metric for downsample of 5m resolution blocks.
- [#2858](https://github.com/thanos-io/thanos/pull/2858) Store: Fix `--store.grpc.series-sample-limit` implementation. The limit is now applied to the sum of all samples fetched across all queried blocks via a single Series call, instead of applying it individually to each block.
- [#2936](https://github.com/thanos-io/thanos/pull/2936) Compact: Fix ReplicaLabelRemover panic when replicaLabels are not specified.
- [#2956](https://github.com/thanos-io/thanos/pull/2956) Store: Fix fetching of chunks bigger than 16000 bytes.
- [#2970](https://github.com/thanos-io/thanos/pull/2970) Store: Upgrade minio-go/v7 to fix slowness when running on EKS.
- [#2957](https://github.com/thanos-io/thanos/pull/2957) Rule: _breaking :warning:_ Now sets all of the relevant fields properly; avoids a panic when `/api/v1/rules` is called and the time zone is _not_ UTC; `rules` field is an empty array now if no rules have been defined in a rule group.
  Thanos Rule's `/api/v1/rules` endpoint no longer returns the old, deprecated `partial_response_strategy`. The old, deprecated value has been fixed to `WARN` for quite some time. _Please_ use `partialResponseStrategy`.
- [#2976](https://github.com/thanos-io/thanos/pull/2976) Query: Better rounding for incoming query timestamps.
- [#2929](https://github.com/thanos-io/thanos/pull/2929) Mixin: Fix expression for 'unhealthy sidecar' alert and increase the timeout for 10 minutes.
- [#3024](https://github.com/thanos-io/thanos/pull/3024) Query: Consider group name and file for deduplication.
- [#3012](https://github.com/thanos-io/thanos/pull/3012) Ruler,Receiver: Fix TSDB to delete blocks in atomic way.
- [#3046](https://github.com/thanos-io/thanos/pull/3046) Ruler,Receiver: Fixed framing of StoreAPI response, it was one chunk by one.
- [#3095](https://github.com/thanos-io/thanos/pull/3095) Ruler: Update the manager when all rule files are removed.
- [#3105](https://github.com/thanos-io/thanos/pull/3105) Querier: Fix overwriting `maxSourceResolution` when auto downsampling is enabled.
- [#3010](https://github.com/thanos-io/thanos/pull/3010) Querier: Added `--query.lookback-delta` flag to override the default lookback delta in PromQL. The flag should be lookback delta should be set to at least 2 times of the slowest scrape interval. If unset it will use the PromQL default of 5m.

### Added

- [#2305](https://github.com/thanos-io/thanos/pull/2305) Receive,Sidecar,Ruler: Propagate correct (stricter) MinTime for TSDBs that have no block.
- [#2849](https://github.com/thanos-io/thanos/pull/2849) Query, Ruler: Added request logging for HTTP server side.
- [#2832](https://github.com/thanos-io/thanos/pull/2832) ui React: Add runtime and build info page
- [#2926](https://github.com/thanos-io/thanos/pull/2926) API: Add new blocks HTTP API to serve blocks metadata. The status endpoints (`/api/v1/status/flags`, `/api/v1/status/runtimeinfo` and `/api/v1/status/buildinfo`) are now available on all components with a HTTP API.
- [#2892](https://github.com/thanos-io/thanos/pull/2892) Receive: Receiver fails when the initial upload fails.
- [#2865](https://github.com/thanos-io/thanos/pull/2865) ui: Migrate Thanos Ruler UI to React
- [#2964](https://github.com/thanos-io/thanos/pull/2964) Query: Add time range parameters to label APIs. Add `start` and `end` fields to Store API `LabelNamesRequest` and `LabelValuesRequest`.
- [#2996](https://github.com/thanos-io/thanos/pull/2996) Sidecar: Add `reloader_config_apply_errors_total` metric. Add new flags `--reloader.watch-interval`, and `--reloader.retry-interval`.
- [#2973](https://github.com/thanos-io/thanos/pull/2973) Add Thanos Query Frontend component.
- [#2980](https://github.com/thanos-io/thanos/pull/2980) Bucket Viewer: Migrate block viewer to React.
- [#2725](https://github.com/thanos-io/thanos/pull/2725) Add bucket index operation durations: `thanos_bucket_store_cached_series_fetch_duration_seconds` and `thanos_bucket_store_cached_postings_fetch_duration_seconds`.
- [#2931](https://github.com/thanos-io/thanos/pull/2931) Query: Allow passing a `storeMatch[]` to select matching stores when debugging the querier. See [documentation](https://thanos.io/tip/components/query.md/#store-filtering)

### Changed

- [#2893](https://github.com/thanos-io/thanos/pull/2893) Store: Rename metric `thanos_bucket_store_cached_postings_compression_time_seconds` to `thanos_bucket_store_cached_postings_compression_time_seconds_total`.
- [#2915](https://github.com/thanos-io/thanos/pull/2915) Receive,Ruler: Enable TSDB directory locking by default. Add a new flag (`--tsdb.no-lockfile`) to override behavior.
- [#2902](https://github.com/thanos-io/thanos/pull/2902) Querier UI:Separate dedupe and partial response checkboxes per panel in new UI.
- [#2991](https://github.com/thanos-io/thanos/pull/2991) Store: _breaking :warning:_ `operation` label value `getrange` changed to `get_range` for `thanos_store_bucket_cache_operation_requests_total` and `thanos_store_bucket_cache_operation_hits_total` to be consistent with bucket operation metrics.
- [#2876](https://github.com/thanos-io/thanos/pull/2876) Receive,Ruler: Updated TSDB and switched to ChunkIterators instead of sample one, which avoids unnecessary decoding / encoding.
- [#3064](https://github.com/thanos-io/thanos/pull/3064) s3: _breaking :warning:_ Add SSE/SSE-KMS/SSE-C configuration. The S3 `encrypt_sse: true` option is now deprecated in favour of `sse_config`. If you used `encrypt_sse`, the migration strategy is to set up the following block:

```yaml
sse_config:
  type: SSE-S3
```

## [v0.14.0](https://github.com/thanos-io/thanos/releases/tag/v0.14.0) - 2020.07.10

### Fixed

- [#2637](https://github.com/thanos-io/thanos/pull/2637) Compact: Detect retryable errors that are inside of a wrapped `tsdb.MultiError`.
- [#2648](https://github.com/thanos-io/thanos/pull/2648) Store: Allow index cache and caching bucket to be configured at the same time.
- [#2728](https://github.com/thanos-io/thanos/pull/2728) Query: Fixed panics when using larger number of replica labels with short series label sets.
- [#2787](https://github.com/thanos-io/thanos/pull/2787) Update Prometheus mod to pull in prometheus/prometheus#7414.
- [#2807](https://github.com/thanos-io/thanos/pull/2807) Store: Decreased memory allocations while querying block's index.
- [#2809](https://github.com/thanos-io/thanos/pull/2809) Query: `/api/v1/stores` now guarantees to return a string in the `lastError` field.

### Changed

- [#2658](https://github.com/thanos-io/thanos/pull/2658) [#2703](https://github.com/thanos-io/thanos/pull/2703) Upgrade to Prometheus [@3268eac2ddda](https://github.com/prometheus/prometheus/commit/3268eac2ddda) which is after v2.18.1.
  - TSDB now does memory-mapping of Head chunks and reduces memory usage.
- [#2667](https://github.com/thanos-io/thanos/pull/2667) Store: Removed support to the legacy `index.cache.json`. The hidden flag `--store.disable-index-header` was removed.
- [#2613](https://github.com/thanos-io/thanos/pull/2613) Store: Renamed the caching bucket config option `chunk_object_size_ttl` to `chunk_object_attrs_ttl`.
- [#2667](https://github.com/thanos-io/thanos/pull/2667) Compact: The deprecated flag `--index.generate-missing-cache-file` and the metric `thanos_compact_generated_index_total` were removed.
- [#2671](https://github.com/thanos-io/thanos/pull/2671) _breaking_ Tools: Bucket replicate flag `--resolution` is now in Go duration format.
- [#2671](https://github.com/thanos-io/thanos/pull/2671) Tools: Bucket replicate now replicates by default all blocks.
- [#2739](https://github.com/thanos-io/thanos/pull/2739) Changed `bucket tool bucket verify` `--id-whitelist` flag to `--id`.
- [#2748](https://github.com/thanos-io/thanos/pull/2748) Upgrade Prometheus to [@66dfb951c4ca](https://github.com/prometheus/prometheus/commit/66dfb951c4ca2c1dd3f266172a48a925403b13a5) which is after v2.19.0.
  - PromQL now allow us to executed concurrent selects.

### Added

- [#2671](https://github.com/thanos-io/thanos/pull/2671) Tools: Bucket replicate now allows passing repeated `--compaction` and `--resolution` flags.
- [#2657](https://github.com/thanos-io/thanos/pull/2657) Querier: Add the ability to perform concurrent select request per query.
- [#2754](https://github.com/thanos-io/thanos/pull/2754) UI: Add stores page in the React UI.
- [#2752](https://github.com/thanos-io/thanos/pull/2752) Compact: Add flag `--block-viewer.global.sync-block-interval` to configure metadata sync interval for the bucket UI.

## [v0.13.0](https://github.com/thanos-io/thanos/releases/tag/v0.13.0) - 2020.06.22

### Fixed

- [#2548](https://github.com/thanos-io/thanos/pull/2548) Query: Fixed rare cases of double counter reset accounting when querying `rate` with deduplication enabled.
- [#2536](https://github.com/thanos-io/thanos/pull/2536) S3: Fixed AWS STS endpoint url to https for Web Identity providers on AWS EKS.
- [#2501](https://github.com/thanos-io/thanos/pull/2501) Query: Gracefully handle additional fields in `SeriesResponse` protobuf message that may be added in the future.
- [#2568](https://github.com/thanos-io/thanos/pull/2568) Query: Don't close the connection of strict, static nodes if establishing a connection had succeeded but Info() call failed.
- [#2615](https://github.com/thanos-io/thanos/pull/2615) Rule: Fix bugs where rules were out of sync.
- [#2614](https://github.com/thanos-io/thanos/pull/2614) Tracing: Disabled Elastic APM Go Agent default tracer on initialization to disable the default metric gatherer.
- [#2525](https://github.com/thanos-io/thanos/pull/2525) Query: Fixed logging for dns resolution error in the `Query` component.
- [#2484](https://github.com/thanos-io/thanos/pull/2484) Query/Ruler: Fixed issue #2483, when web.route-prefix is set, it is added twice in HTTP router prefix.
- [#2416](https://github.com/thanos-io/thanos/pull/2416) Bucket: Fixed issue #2416 bug in `inspect --sort-by` doesn't work correctly in all cases.
- [#2719](https://github.com/thanos-io/thanos/pull/2719) Query: `irate` and `resets` use now counter downsampling aggregations.
- [#2705](https://github.com/thanos-io/thanos/pull/2705) minio-go: Added support for `af-south-1` and `eu-south-1` regions.
- [#2753](https://github.com/thanos-io/thanos/issues/2753) Sidecar, Receive, Rule: Fixed possibility of out of order uploads in error cases. This could potentially cause Compactor to create overlapping blocks.

### Added

- [#2012](https://github.com/thanos-io/thanos/pull/2012) Receive: Added multi-tenancy support (based on header)
- [#2502](https://github.com/thanos-io/thanos/pull/2502) StoreAPI: Added `hints` field to `SeriesResponse`. Hints in an opaque data structure that can be used to carry additional information from the store and its content is implementation specific.
- [#2521](https://github.com/thanos-io/thanos/pull/2521) Sidecar: Added `thanos_sidecar_reloader_reloads_failed_total`, `thanos_sidecar_reloader_reloads_total`, `thanos_sidecar_reloader_watch_errors_total`, `thanos_sidecar_reloader_watch_events_total` and `thanos_sidecar_reloader_watches` metrics.
- [#2412](https://github.com/thanos-io/thanos/pull/2412) UI: Added React UI from Prometheus upstream. Currently only accessible from Query component as only `/graph` endpoint is migrated.
- [#2532](https://github.com/thanos-io/thanos/pull/2532) Store: Added hidden option `--store.caching-bucket.config=<yaml content>` (or `--store.caching-bucket.config-file=<file.yaml>`) for experimental caching bucket, that can cache chunks into shared memcached. This can speed up querying and reduce number of requests to object storage.
- [#2579](https://github.com/thanos-io/thanos/pull/2579) Store: Experimental caching bucket can now cache metadata as well. Config has changed from #2532.
- [#2526](https://github.com/thanos-io/thanos/pull/2526) Compact: In case there are no labels left after deduplication via `--deduplication.replica-label`, assign first `replica-label` with value `deduped`.
- [#2621](https://github.com/thanos-io/thanos/pull/2621) Receive: Added flag to configure forward request timeout. Receive write will complete request as soon as quorum of writes succeeds.

### Changed

- [#2194](https://github.com/thanos-io/thanos/pull/2194) Updated to golang v1.14.2.
- [#2505](https://github.com/thanos.io/thanos/pull/2505) Store: Removed obsolete `thanos_store_node_info` metric.
- [#2513](https://github.com/thanos-io/thanos/pull/2513) Tools: Moved `thanos bucket` commands to `thanos tools bucket`, also
  moved `thanos check rules` to `thanos tools rules-check`. `thanos tools rules-check` also takes rules by `--rules` repeated flag not argument
  anymore.
- [#2548](https://github.com/thanos-io/thanos/pull/2548/commits/53e69bd89b2b08c18df298eed7d90cb7179cc0ec) Store, Querier: remove duplicated chunks on StoreAPI.
- [#2596](https://github.com/thanos-io/thanos/pull/2596) Updated Prometheus dependency to [@cd73b3d33e064bbd846fc7a26dc8c313d46af382](https://github.com/prometheus/prometheus/commit/cd73b3d33e064bbd846fc7a26dc8c313d46af382) which falls in between v2.17.0 and v2.18.0.
  - Receive,Rule: TSDB now supports isolation of append and queries.
  - Receive,Rule: TSDB now holds less WAL files after Head Truncation.
- [#2450](https://github.com/thanos-io/thanos/pull/2450) Store: Added Regex-set optimization for `label=~"a|b|c"` matchers.
- [#2526](https://github.com/thanos-io/thanos/pull/2526) Compact: In case there are no labels left after deduplication via `--deduplication.replica-label`, assign first `replica-label` with value `deduped`.
- [#2603](https://github.com/thanos-io/thanos/pull/2603) Store/Querier: Significantly optimize cases where StoreAPIs or blocks returns exact overlapping chunks (e.g Store GW and sidecar or brute force Store Gateway HA).

## [v0.12.2](https://github.com/thanos-io/thanos/releases/tag/v0.12.2) - 2020.04.30

### Fixed

- [#2459](https://github.com/thanos-io/thanos/issues/2459) Compact: Fixed issue with old blocks being marked and deleted in a (slow) loop.
- [#2533](https://github.com/thanos-io/thanos/pull/2515) Rule: do not wrap reload endpoint with `/`. Makes `/-/reload` accessible again when no prefix has been specified.

## [v0.12.1](https://github.com/thanos-io/thanos/releases/tag/v0.12.1) - 2020.04.20

### Fixed

- [#2411](https://github.com/thanos-io/thanos/pull/2411) Query: fix a bug where queries might not time out sometimes due to issues with one or more StoreAPIs.
- [#2475](https://github.com/thanos-io/thanos/pull/2475) Store: remove incorrect optimizations for queries with `=~".*"` and `!=~".*"` matchers.
- [#2472](https://github.com/thanos-io/thanos/pull/2472) Compact: fix a bug where partial blocks were never deleted, causing spam of warnings.
- [#2474](https://github.com/thanos-io/thanos/pull/2474) Store: fix a panic caused by concurrent memory access during block filtering.

## [v0.12.0](https://github.com/thanos-io/thanos/releases/tag/v0.12.0) - 2020.04.15

### Fixed

- [#2288](https://github.com/thanos-io/thanos/pull/2288) Ruler: fixes issue #2281, a bug causing incorrect parsing of query address with path prefix.
- [#2238](https://github.com/thanos-io/thanos/pull/2238) Ruler: fixed issue #2204, where a bug in alert queue signaling filled up the queue and alerts were dropped.
- [#2231](https://github.com/thanos-io/thanos/pull/2231) Bucket Web: sort chunks by thanos.downsample.resolution for better grouping.
- [#2254](https://github.com/thanos-io/thanos/pull/2254) Bucket: fix issue where metrics were registered multiple times in bucket replicate.
- [#2271](https://github.com/thanos-io/thanos/pull/2271) Bucket Web: fixed issue #2260, where the bucket passes null when storage is empty.
- [#2339](https://github.com/thanos-io/thanos/pull/2339) Query: fix a bug where `--store.unhealthy-timeout` was never respected.
- [#2208](https://github.com/thanos-io/thanos/pull/2208) Query and Rule: fix handling of `web.route-prefix` to correctly handle `/` and prefixes that do not begin with a `/`.
- [#2311](https://github.com/thanos-io/thanos/pull/2311) Receive: ensure receive component serves TLS when TLS configuration is provided.
- [#2319](https://github.com/thanos-io/thanos/pull/2319) Query: fixed inconsistent naming of metrics.
- [#2390](https://github.com/thanos-io/thanos/pull/2390) Store: fixed bug that was causing all posting offsets to be used instead of only 1/32 as intended; added hidden flag to control this behavior.
- [#2393](https://github.com/thanos-io/thanos/pull/2393) Store: fixed bug causing certain not-existing label values queried to fail with "invalid-size" error from binary header.
- [#2382](https://github.com/thanos-io/thanos/pull/2382) Store: fixed bug causing partial writes of index-header.
- [#2383](https://github.com/thanos-io/thanos/pull/2383) Store: handle expected errors correctly, e.g. do not increment failure counters.

### Added

- [#2252](https://github.com/thanos-io/thanos/pull/2252) Query: add new `--store-strict` flag. More information available [here](/docs/proposals/202001_thanos_query_health_handling.md).
- [#2265](https://github.com/thanos-io/thanos/pull/2265) Compact: add `--wait-interval` to specify compaction wait interval between consecutive compact runs when `--wait` is enabled.
- [#2250](https://github.com/thanos-io/thanos/pull/2250) Compact: enable vertical compaction for offline deduplication (experimental). Uses `--deduplication.replica-label` flag to specify the replica label on which to deduplicate (hidden). Please note that this uses a NAIVE algorithm for merging (no smart replica deduplication, just chaining samples together). This works well for deduplication of blocks with **precisely the same samples** like those produced by Receiver replication. We plan to add a smarter algorithm in the following weeks.
- [#1714](https://github.com/thanos-io/thanos/pull/1714) Compact: the compact component now exposes the bucket web UI when it is run as a long-lived process.
- [#2304](https://github.com/thanos-io/thanos/pull/2304) Store: added `max_item_size` configuration option to memcached-based index cache. This should be set to the max item size configured in memcached (`-I` flag) in order to not waste network round-trips to cache items larger than the limit configured in memcached.
- [#2297](https://github.com/thanos-io/thanos/pull/2297) Store: add `--experimental.enable-index-cache-postings-compression` flag to enable re-encoding and compressing postings before storing them into the cache. Compressed postings take about 10% of the original size.
- [#2357](https://github.com/thanos-io/thanos/pull/2357) Compact and Store: the compact and store components now serve the bucket UI on `:<http-port>/loaded`, which shows exactly the blocks that are currently seen by compactor and the store gateway. The compactor also serves a different bucket UI on `:<http-port>/global`, which shows the status of object storage without any filters.
- [#2172](https://github.com/thanos-io/thanos/pull/2172) Store: add support for sharding the store component based on the label hash.
- [#2113](https://github.com/thanos-io/thanos/pull/2113) Bucket: added `thanos bucket replicate` command to replicate blocks from one bucket to another.
- [#1922](https://github.com/thanos-io/thanos/pull/1922) Docs: create a new document to explain sharding in Thanos.
- [#2230](https://github.com/thanos-io/thanos/pull/2230) Store: optimize conversion of labels.

### Changed

- [#2136](https://github.com/thanos-io/thanos/pull/2136) _breaking_ Store, Compact, Bucket: schedule block deletion by adding deletion-mark.json. This adds a consistent way for multiple readers and writers to access object storage.
  Since there are no consistency guarantees provided by some Object Storage providers, this PR adds a consistent lock-free way of dealing with Object Storage irrespective of the choice of object storage. In order to achieve this co-ordination, blocks are not deleted directly. Instead, blocks are marked for deletion by uploading the `deletion-mark.json` file for the block that was chosen to be deleted. This file contains Unix time of when the block was marked for deletion. If you want to keep existing behavior, you should add `--delete-delay=0s` as a flag.
- [#2090](https://github.com/thanos-io/thanos/issues/2090) _breaking_ Downsample command: the `downsample` command has moved and is now a sub-command of the `thanos bucket` sub-command; it cannot be called via `thanos downsample` any more.
- [#2294](https://github.com/thanos-io/thanos/pull/2294) Store: optimizations for fetching postings. Queries using `=~".*"` matchers or negation matchers (`!=...` or `!~...`) benefit the most.
- [#2301](https://github.com/thanos-io/thanos/pull/2301) Ruler: exit with an error when initialization fails.
- [#2310](https://github.com/thanos-io/thanos/pull/2310) Query: report timespan 0 to 0 when discovering no stores.
- [#2330](https://github.com/thanos-io/thanos/pull/2330) Store: index-header is no longer experimental. It is enabled by default for store Gateway. You can disable it with new hidden flag: `--store.disable-index-header`. The `--experimental.enable-index-header` flag was removed.
- [#1848](https://github.com/thanos-io/thanos/pull/1848) Ruler: allow returning error messages when a reload is triggered via HTTP.
- [#2270](https://github.com/thanos-io/thanos/pull/2277) All: Thanos components will now print stack traces when they error out.

## [v0.11.0](https://github.com/thanos-io/thanos/releases/tag/v0.11.0) - 2020.03.02

### Fixed

- [#2033](https://github.com/thanos-io/thanos/pull/2033) Minio-go: Fixed Issue #1494 support Web Identity providers for IAM credentials for AWS EKS.
- [#1985](https://github.com/thanos-io/thanos/pull/1985) Store Gateway: Fixed case where series entry is larger than 64KB in index.
- [#2051](https://github.com/thanos-io/thanos/pull/2051) Ruler: Fixed issue where ruler does not expose shipper metrics.
- [#2101](https://github.com/thanos-io/thanos/pull/2101) Ruler: Fixed bug where thanos_alert_sender_errors_total was not registered.
- [#1789](https://github.com/thanos-io/thanos/pull/1789) Store Gateway: Improve timeouts.
- [#2139](https://github.com/thanos-io/thanos/pull/2139) Properly handle SIGHUP for reloading.
- [#2040](https://github.com/thanos-io/thanos/pull/2040) UI: Fix URL of alerts in Ruler
- [#2033](https://github.com/thanos-io/thanos/pull/1978) Ruler: Fix tracing in Thanos Ruler

### Added

- [#2003](https://github.com/thanos-io/thanos/pull/2003) Query: Support downsampling for /series.
- [#1952](https://github.com/thanos-io/thanos/pull/1952) Store Gateway: Implemented [binary index header](https://thanos.io/tip/proposals/201912_thanos_binary_index_header.md/). This significantly reduces resource consumption (memory, CPU, net bandwidth) for startup and data loading processes as well as baseline memory. This means that adding more blocks into object storage, without querying them will use almost no resources. This, however, **still means that querying large amounts of data** will result in high spikes of memory and CPU use as before, due to simply fetching large amounts of metrics data. Since we fixed baseline, we are now focusing on query performance optimizations in separate initiatives. To enable experimental `index-header` mode run store with hidden `experimental.enable-index-header` flag.
- [#2009](https://github.com/thanos-io/thanos/pull/2009) Store Gateway: Minimum age of all blocks before they are being read. Set it to a safe value (e.g 30m) if your object storage is eventually consistent. GCS and S3 are (roughly) strongly consistent.
- [#1963](https://github.com/thanos-io/thanos/pull/1963) Mixin: Add Thanos Ruler alerts.
- [#1984](https://github.com/thanos-io/thanos/pull/1984) Query: Add cache-control header to not cache on error.
- [#1870](https://github.com/thanos-io/thanos/pull/1870) UI: Persist settings in query.
- [#1969](https://github.com/thanos-io/thanos/pull/1969) Sidecar: allow setting http connection pool size via flags.
- [#1967](https://github.com/thanos-io/thanos/issues/1967) Receive: Allow local TSDB compaction.
- [#1939](https://github.com/thanos-io/thanos/pull/1939) Ruler: Add TLS and authentication support for query endpoints with the `--query.config` and `--query.config-file` CLI flags. See [documentation](docs/components/rule.md/#configuration) for further information.
- [#1982](https://github.com/thanos-io/thanos/pull/1982) Ruler: Add support for Alertmanager v2 API endpoints.
- [#2030](https://github.com/thanos-io/thanos/pull/2030) Query: Add `thanos_proxy_store_empty_stream_responses_total` metric for number of empty responses from stores.
- [#2049](https://github.com/thanos-io/thanos/pull/2049) Tracing: Support sampling on Elastic APM with new sample_rate setting.
- [#2008](https://github.com/thanos-io/thanos/pull/2008) Querier, Receiver, Sidecar, Store: Add gRPC [health check](https://github.com/grpc/grpc/blob/master/doc/health-checking.md) endpoints.
- [#2145](https://github.com/thanos-io/thanos/pull/2145) Tracing: track query sent to prometheus via remote read api.

### Changed

- [#1970](https://github.com/thanos-io/thanos/issues/1970) _breaking_ Receive: Use gRPC for forwarding requests between peers. Note that existing values for the `--receive.local-endpoint` flag and the endpoints in the hashring configuration file must now specify the receive gRPC port and must be updated to be a simple `host:port` combination, e.g. `127.0.0.1:10901`, rather than a full HTTP URL, e.g. `http://127.0.0.1:10902/api/v1/receive`.
- [#1933](https://github.com/thanos-io/thanos/pull/1933) Add a flag `--tsdb.wal-compression` to configure whether to enable tsdb wal compression in ruler and receiver.
- [#2021](https://github.com/thanos-io/thanos/pull/2021) Rename metric `thanos_query_duplicated_store_address` to `thanos_query_duplicated_store_addresses_total` and `thanos_rule_duplicated_query_address` to `thanos_rule_duplicated_query_addresses_total`.
- [#2166](https://github.com/thanos-io/thanos/pull/2166) Bucket Web: improve the tooltip for the bucket UI; it was reconstructed and now exposes much more information about blocks.

## [v0.10.1](https://github.com/thanos-io/thanos/releases/tag/v0.10.1) - 2020.01.24

### Fixed

- [#2015](https://github.com/thanos-io/thanos/pull/2015) Sidecar: Querier /api/v1/series bug fixed when time range was ignored inside sidecar.
  The bug was noticeable for example when using Grafana template variables.
- [#2120](https://github.com/thanos-io/thanos/pull/2120) Bucket Web: Set state of status prober properly.

## [v0.10.0](https://github.com/thanos-io/thanos/releases/tag/v0.10.0) - 2020.01.13

### Fixed

- [#1919](https://github.com/thanos-io/thanos/issues/1919) Compactor: Fixed potential data loss when uploading older blocks, or upload taking long time while compactor is
  running.
- [#1937](https://github.com/thanos-io/thanos/pull/1937) Compactor: Improved synchronization of meta JSON files.
  Compactor now properly handles partial block uploads for all operation like retention apply, downsampling and compaction. Additionally:

  - Removed `thanos_compact_sync_meta_*` metrics. Use `thanos_blocks_meta_*` metrics instead.
  - Added `thanos_consistency_delay_seconds` and `thanos_compactor_aborted_partial_uploads_deletion_attempts_total` metrics.

- [#1936](https://github.com/thanos-io/thanos/pull/1936) Store: Improved synchronization of meta JSON files. Store now properly handles corrupted disk cache. Added meta.json sync metrics.
- [#1856](https://github.com/thanos-io/thanos/pull/1856) Receive: close DBReadOnly after flushing to fix a memory leak.
- [#1882](https://github.com/thanos-io/thanos/pull/1882) Receive: upload to object storage as 'receive' rather than 'sidecar'.
- [#1907](https://github.com/thanos-io/thanos/pull/1907) Store: Fixed the duration unit for the metric `thanos_bucket_store_series_gate_duration_seconds`.
- [#1931](https://github.com/thanos-io/thanos/pull/1931) Compact: Fixed the compactor successfully exiting when actually an error occurred while compacting a blocks group.
- [#1872](https://github.com/thanos-io/thanos/pull/1872) Ruler: `/api/v1/rules` now shows a properly formatted value
- [#1945](https://github.com/thanos-io/thanos/pull/1945) `master` container images are now built with Go 1.13
- [#1956](https://github.com/thanos-io/thanos/pull/1956) Ruler: now properly ignores duplicated query addresses
- [#1975](https://github.com/thanos-io/thanos/pull/1975) Store Gateway: fixed panic caused by memcached servers selector when there's 1 memcached node

### Added

- [#1852](https://github.com/thanos-io/thanos/pull/1852) Add support for `AWS_CONTAINER_CREDENTIALS_FULL_URI` by upgrading to minio-go v6.0.44
- [#1854](https://github.com/thanos-io/thanos/pull/1854) Update Rule UI to support alerts count displaying and filtering.
- [#1838](https://github.com/thanos-io/thanos/pull/1838) Ruler: Add TLS and authentication support for Alertmanager with the `--alertmanagers.config` and `--alertmanagers.config-file` CLI flags. See [documentation](docs/components/rule.md/#configuration) for further information.
- [#1838](https://github.com/thanos-io/thanos/pull/1838) Ruler: Add a new `--alertmanagers.sd-dns-interval` CLI option to specify the interval between DNS resolutions of Alertmanager hosts.
- [#1881](https://github.com/thanos-io/thanos/pull/1881) Store Gateway: memcached support for index cache. See [documentation](docs/components/store.md/#index-cache) for further information.
- [#1904](https://github.com/thanos-io/thanos/pull/1904) Add a skip-chunks option in Store Series API to improve the response time of `/api/v1/series` endpoint.
- [#1910](https://github.com/thanos-io/thanos/pull/1910) Query: `/api/v1/labels` now understands `POST` - useful for sending bigger requests

### Changed

- [#1947](https://github.com/thanos-io/thanos/pull/1947) Upgraded Prometheus dependencies to v2.15.2. This includes:

  - Compactor: Significant reduction of memory footprint for compaction and downsampling process.
  - Querier: Accepting spaces between time range and square bracket. e.g `[ 5m]`
  - Querier: Improved PromQL parser performance.

- [#1833](https://github.com/thanos-io/thanos/pull/1833) `--shipper.upload-compacted` flag has been promoted to non hidden, non experimental state. More info available [here](docs/quick-tutorial.md#uploading-old-metrics).
- [#1867](https://github.com/thanos-io/thanos/pull/1867) Ruler: now sets a `Thanos/$version` `User-Agent` in requests
- [#1887](https://github.com/thanos-io/thanos/pull/1887) Service discovery now deduplicates targets between different target groups

## [v0.9.0](https://github.com/thanos-io/thanos/releases/tag/v0.9.0) - 2019.12.03

### Added

- [#1678](https://github.com/thanos-io/thanos/pull/1678) Add Lightstep as a tracing provider.
- [#1687](https://github.com/thanos-io/thanos/pull/1687) Add a new `--grpc-grace-period` CLI option to components which serve gRPC to set how long to wait until gRPC Server shuts down.
- [#1660](https://github.com/thanos-io/thanos/pull/1660) Sidecar: Add a new `--prometheus.ready_timeout` CLI option to the sidecar to set how long to wait until Prometheus starts up.
- [#1573](https://github.com/thanos-io/thanos/pull/1573) `AliYun OSS` object storage, see [documents](docs/storage.md#aliyun-oss) for further information.
- [#1680](https://github.com/thanos-io/thanos/pull/1680) Add a new `--http-grace-period` CLI option to components which serve HTTP to set how long to wait until HTTP Server shuts down.
- [#1712](https://github.com/thanos-io/thanos/pull/1712) Bucket: Rename flag on bucket web component from `--listen` to `--http-address` to match other components.
- [#1733](https://github.com/thanos-io/thanos/pull/1733) Compactor: New metric `thanos_compactor_iterations_total` on Thanos Compactor which shows the number of successful iterations.
- [#1758](https://github.com/thanos-io/thanos/pull/1758) Bucket: `thanos bucket web` now supports `--web.external-prefix` for proxying on a subpath.
- [#1770](https://github.com/thanos-io/thanos/pull/1770) Bucket: Add `--web.prefix-header` flags to allow for bucket UI to be accessible behind a reverse proxy.
- [#1668](https://github.com/thanos-io/thanos/pull/1668) Receiver: Added TLS options for both server and client remote write.

### Fixed

- [#1656](https://github.com/thanos-io/thanos/pull/1656) Store Gateway: Store now starts metric and status probe HTTP server earlier in its start-up sequence. `/-/healthy` endpoint now starts to respond with success earlier. `/metrics` endpoint starts serving metrics earlier as well. Make sure to point your readiness probes to the `/-/ready` endpoint rather than `/metrics`.
- [#1669](https://github.com/thanos-io/thanos/pull/1669) Store Gateway: Fixed store sharding. Now it does not load excluded meta.jsons and load/fetch index-cache.json files.
- [#1670](https://github.com/thanos-io/thanos/pull/1670) Sidecar: Fixed un-ordered blocks upload. Sidecar now uploads the oldest blocks first.
- [#1568](https://github.com/thanos-io/thanos/pull/1709) Store Gateway: Store now retains the first raw value of a chunk during downsampling to avoid losing some counter resets that occur on an aggregation boundary.
- [#1751](https://github.com/thanos-io/thanos/pull/1751) Querier: Fixed labels for StoreUI
- [#1773](https://github.com/thanos-io/thanos/pull/1773) Ruler: Fixed the /api/v1/rules endpoint that returned 500 status code with `failed to assert type of rule ...` message.
- [#1770](https://github.com/thanos-io/thanos/pull/1770) Querier: Fixed `--web.external-prefix` 404s for static resources.
- [#1785](https://github.com/thanos-io/thanos/pull/1785) Ruler: The /api/v1/rules endpoints now returns the original rule filenames.
- [#1791](https://github.com/thanos-io/thanos/pull/1791) Ruler: Ruler now supports identical rule filenames in different directories.
- [#1562](https://github.com/thanos-io/thanos/pull/1562) Querier: Downsampling option now carries through URL.
- [#1675](https://github.com/thanos-io/thanos/pull/1675) Querier: Reduced resource usage while using certain queries like `offset`.
- [#1725](https://github.com/thanos-io/thanos/pull/1725) & [#1718](https://github.com/thanos-io/thanos/pull/1718) Store Gateway: Per request memory improvements.

### Changed

- [#1666](https://github.com/thanos-io/thanos/pull/1666) Compact: `thanos_compact_group_compactions_total` now counts block compactions, so operations that resulted in a compacted block. The old behaviour
  is now exposed by new metric: `thanos_compact_group_compaction_runs_started_total` and `thanos_compact_group_compaction_runs_completed_total` which counts compaction runs overall.
- [#1748](https://github.com/thanos-io/thanos/pull/1748) Updated all dependencies.
- [#1694](https://github.com/thanos-io/thanos/pull/1694) `prober_ready` and `prober_healthy` metrics are removed, for sake of `status`. Now `status` exposes same metric with a label, `check`. `check` can have "healty" or "ready" depending on status of the probe.
- [#1790](https://github.com/thanos-io/thanos/pull/1790) Ruler: Fixes subqueries support for ruler.
- [#1769](https://github.com/thanos-io/thanos/pull/1769) & [#1545](https://github.com/thanos-io/thanos/pull/1545) Adjusted most of the metrics histogram buckets.

## [v0.8.1](https://github.com/thanos-io/thanos/releases/tag/v0.8.1) - 2019.10.14

### Fixed

- [#1632](https://github.com/thanos-io/thanos/issues/1632) Removes the duplicated external labels detection on Thanos Querier; warning only; Made Store Gateway compatible with older Querier versions.
  - NOTE: `thanos_store_nodes_grpc_connections` metric is now per `external_labels` and `store_type`. It is a recommended metric for Querier storeAPIs. `thanos_store_node_info` is marked as obsolete and will be removed in next release.
  - NOTE2: Store Gateway is now advertising artificial: `"@thanos_compatibility_store_type=store"` label. This is to have the current Store Gateway compatible with Querier pre v0.8.0.
    This label can be disabled by hidden `debug.advertise-compatibility-label=false` flag on Store Gateway.

## [v0.8.0](https://github.com/thanos-io/thanos/releases/tag/v0.8.0) - 2019.10.10

Lot's of improvements this release! Noteworthy items:

- First Katacoda tutorial! 🐱
- Fixed Deletion order causing Compactor to produce not needed 👻 blocks with missing random files.
- Store GW memory improvements (more to come!).
- Querier allows multiple deduplication labels.
- Both Compactor and Store Gateway can be **sharded** within the same bucket using relabelling!
- Sidecar exposed data from Prometheus can be now limited to given `min-time` (e.g 3h only).
- Numerous Thanos Receive improvements.

Make sure you check out Prometheus 2.13.0 as well. New release drastically improves usage and resource consumption of
both Prometheus and sidecar with Thanos: https://prometheus.io/blog/2019/10/10/remote-read-meets-streaming/

### Added

- [#1619](https://github.com/thanos-io/thanos/pull/1619) Thanos sidecar allows to limit min time range for data it exposes from Prometheus.
- [#1583](https://github.com/thanos-io/thanos/pull/1583) Thanos sharding:
  - Add relabel config (`--selector.relabel-config-file` and `selector.relabel-config`) into Thanos Store and Compact components.
    Selecting blocks to serve depends on the result of block labels relabeling.
  - For store gateway, advertise labels from "approved" blocks.
- [#1540](https://github.com/thanos-io/thanos/pull/1540) Thanos Downsample added `/-/ready` and `/-/healthy` endpoints.
- [#1538](https://github.com/thanos-io/thanos/pull/1538) Thanos Rule added `/-/ready` and `/-/healthy` endpoints.
- [#1537](https://github.com/thanos-io/thanos/pull/1537) Thanos Receive added `/-/ready` and `/-/healthy` endpoints.
- [#1460](https://github.com/thanos-io/thanos/pull/1460) Thanos Store Added `/-/ready` and `/-/healthy` endpoints.
- [#1534](https://github.com/thanos-io/thanos/pull/1534) Thanos Query Added `/-/ready` and `/-/healthy` endpoints.
- [#1533](https://github.com/thanos-io/thanos/pull/1533) Thanos inspect now supports the timeout flag.
- [#1496](https://github.com/thanos-io/thanos/pull/1496) Thanos Receive now supports setting block duration.
- [#1362](https://github.com/thanos-io/thanos/pull/1362) Optional `replicaLabels` param for `/query` and
  `/query_range` querier endpoints. When provided overwrite the `query.replica-label` cli flags.
- [#1482](https://github.com/thanos-io/thanos/pull/1482) Thanos now supports Elastic APM as tracing provider.
- [#1612](https://github.com/thanos-io/thanos/pull/1612) Thanos Rule added `resendDelay` flag.
- [#1480](https://github.com/thanos-io/thanos/pull/1480) Thanos Receive flushes storage on hashring change.
- [#1613](https://github.com/thanos-io/thanos/pull/1613) Thanos Receive now traces forwarded requests.

### Changed

- [#1362](https://github.com/thanos-io/thanos/pull/1362) `query.replica-label` configuration can be provided more than
  once for multiple deduplication labels like: `--query.replica-label=prometheus_replica --query.replica-label=service`.
- [#1581](https://github.com/thanos-io/thanos/pull/1581) Thanos Store now can use smaller buffer sizes for Bytes pool; reducing memory for some requests.
- [#1622](https://github.com/thanos-io/thanos/pull/1622) & [#1590](https://github.com/thanos-io/thanos/pull/1590) Upgraded to Go 1.13.1
- [#1498](https://github.com/thanos-io/thanos/pull/1498) Thanos Receive change flag `labels` to `label` to be consistent with other commands.

### Fixed

- [#1525](https://github.com/thanos-io/thanos/pull/1525) Thanos now deletes block's file in correct order allowing to detect partial blocks without problems.
- [#1505](https://github.com/thanos-io/thanos/pull/1505) Thanos Store now removes invalid local cache blocks.
- [#1587](https://github.com/thanos-io/thanos/pull/1587) Thanos Sidecar cleanups all cache dirs after each compaction run.
- [#1582](https://github.com/thanos-io/thanos/pull/1582) Thanos Rule correctly parses Alertmanager URL if there is more `+` in it.
- [#1544](https://github.com/thanos-io/thanos/pull/1544) Iterating over object store is resilient to the edge case for some providers.
- [#1469](https://github.com/thanos-io/thanos/pull/1469) Fixed Azure potential failures (EOF) when requesting more data then blob has.
- [#1512](https://github.com/thanos-io/thanos/pull/1512) Thanos Store fixed memory leak for chunk pool.
- [#1488](https://github.com/thanos-io/thanos/pull/1488) Thanos Rule now now correctly links to query URL from rules and alerts.

## [v0.7.0](https://github.com/thanos-io/thanos/releases/tag/v0.7.0) - 2019.09.02

Accepted into CNCF:

- Thanos moved to new repository <https://github.com/thanos-io/thanos>
- Docker images moved to <https://quay.io/thanos/thanos> and mirrored at <https://hub.docker.com/r/thanosio/thanos>
- Slack moved to <https://slack.cncf.io> `#thanos`/`#thanos-dev`/`#thanos-prs`

### Added

- [#1478](https://github.com/thanos-io/thanos/pull/1478) Thanos components now exposes gRPC server metrics as soon as server starts, to provide more reliable data for instrumentation.
- [#1378](https://github.com/thanos-io/thanos/pull/1378) Thanos Receive now exposes `thanos_receive_config_hash`, `thanos_receive_config_last_reload_successful` and `thanos_receive_config_last_reload_success_timestamp_seconds` metrics to track latest configuration change
- [#1268](https://github.com/thanos-io/thanos/pull/1268) Thanos Sidecar added support for newest Prometheus streaming remote read added [here](https://github.com/prometheus/prometheus/pull/5703). This massively improves memory required by single
  request for both Prometheus and sidecar. Single requests now should take constant amount of memory on sidecar, so resource consumption prediction is now straightforward. This will be used if you have Prometheus `2.13` or `2.12-master`.
- [#1358](https://github.com/thanos-io/thanos/pull/1358) Added `part_size` configuration option for HTTP multipart requests minimum part size for S3 storage type
- [#1363](https://github.com/thanos-io/thanos/pull/1363) Thanos Receive now exposes `thanos_receive_hashring_nodes` and `thanos_receive_hashring_tenants` metrics to monitor status of hash-rings
- [#1395](https://github.com/thanos-io/thanos/pull/1395) Thanos Sidecar added `/-/ready` and `/-/healthy` endpoints to Thanos sidecar.
- [#1297](https://github.com/thanos-io/thanos/pull/1297) Thanos Compact added `/-/ready` and `/-/healthy` endpoints to Thanos compact.
- [#1431](https://github.com/thanos-io/thanos/pull/1431) Thanos Query added hidden flag to allow the use of downsampled resolution data for instant queries.
- [#1408](https://github.com/thanos-io/thanos/pull/1408) Thanos Store Gateway can now allow the specifying of supported time ranges it will serve (time sharding). Flags: `min-time` & `max-time`

### Changed

- [#1414](https://github.com/thanos-io/thanos/pull/1413) Upgraded important dependencies: Prometheus to 2.12-rc.0. TSDB is now part of Prometheus.
- [#1380](https://github.com/thanos-io/thanos/pull/1380) Upgraded important dependencies: Prometheus to 2.11.1 and TSDB to 0.9.1. Some changes affecting Querier:
  - [ENHANCEMENT] Query performance improvement: Efficient iteration and search in HashForLabels and HashWithoutLabels. #5707
  - [ENHANCEMENT] Optimize queries using regexp for set lookups. tsdb#602
  - [BUGFIX] prometheus_tsdb_compactions_failed_total is now incremented on any compaction failure. tsdb#613
  - [BUGFIX] PromQL: Correctly display {**name**="a"}.
- [#1338](https://github.com/thanos-io/thanos/pull/1338) Thanos Query still warns on store API duplicate, but allows a single one from duplicated set. This is gracefully warn about the problematic logic and not disrupt immediately.
- [#1385](https://github.com/thanos-io/thanos/pull/1385) Thanos Compact exposes flag to disable downsampling `downsampling.disable`.

### Fixed

- [#1327](https://github.com/thanos-io/thanos/pull/1327) Thanos Query `/series` API end-point now properly returns an empty array just like Prometheus if there are no results
- [#1302](https://github.com/thanos-io/thanos/pull/1302) Thanos now efficiently reuses HTTP keep-alive connections
- [#1371](https://github.com/thanos-io/thanos/pull/1371) Thanos Receive fixed race condition in hashring
- [#1430](https://github.com/thanos-io/thanos/pull/1430) Thanos fixed value of GOMAXPROCS inside container.
- [#1410](https://github.com/thanos-io/thanos/pull/1410) Fix for CVE-2019-10215

### Deprecated

- [#1458](https://github.com/thanos-io/thanos/pull/1458) Thanos Query and Receive now use common instrumentation middleware. As as result, for sake of `http_requests_total` and `http_request_duration_seconds_bucket`; Thanos Query no longer exposes `thanos_query_api_instant_query_duration_seconds`, `thanos_query_api_range_query_duration_second` metrics and Thanos Receive no longer exposes `thanos_http_request_duration_seconds`, `thanos_http_requests_total`, `thanos_http_response_size_bytes`.
- [#1423](https://github.com/thanos-io/thanos/pull/1423) Thanos Bench deprecated.

## [v0.6.0](https://github.com/thanos-io/thanos/releases/tag/v0.6.0) - 2019.07.18

### Added

- [#1097](https://github.com/thanos-io/thanos/pull/1097) Added `thanos check rules` linter for Thanos rule rules files.

- [#1253](https://github.com/thanos-io/thanos/pull/1253) Add support for specifying a maximum amount of retries when using Azure Blob storage (default: no retries).

- [#1244](https://github.com/thanos-io/thanos/pull/1244) Thanos Compact now exposes new metrics `thanos_compact_downsample_total` and `thanos_compact_downsample_failures_total` which are useful to catch when errors happen

- [#1260](https://github.com/thanos-io/thanos/pull/1260) Thanos Query/Rule now exposes metrics `thanos_querier_store_apis_dns_provider_results` and `thanos_ruler_query_apis_dns_provider_results` which tell how many addresses were configured and how many were actually discovered respectively

- [#1248](https://github.com/thanos-io/thanos/pull/1248) Add a web UI to show the state of remote storage.

- [#1217](https://github.com/thanos-io/thanos/pull/1217) Thanos Receive gained basic hashring support

- [#1262](https://github.com/thanos-io/thanos/pull/1262) Thanos Receive got a new metric `thanos_http_requests_total` which shows how many requests were handled by it

- [#1243](https://github.com/thanos-io/thanos/pull/1243) Thanos Receive got an ability to forward time series data between nodes. Now you can pass the hashring configuration via `--receive.hashrings-file`; the refresh interval `--receive.hashrings-file-refresh-interval`; the name of the local node's name `--receive.local-endpoint`; and finally the header's name which is used to determine the tenant `--receive.tenant-header`.

- [#1147](https://github.com/thanos-io/thanos/pull/1147) Support for the Jaeger tracer has been added!

_breaking_ New common flags were added for configuring tracing: `--tracing.config-file` and `--tracing.config`. You can either pass a file to Thanos with the tracing configuration or pass it in the command line itself. Old `--gcloudtrace.*` flags were removed :warning:

To migrate over the old `--gcloudtrace.*` configuration, your tracing configuration should look like this:

```yaml
---
type: STACKDRIVER
config:
  - service_name: 'foo'
    project_id: '123'
    sample_factor: 123
```

The other `type` you can use is `JAEGER` now. The `config` keys and values are Jaeger specific and you can find all of the information [here](https://github.com/jaegertracing/jaeger-client-go#environment-variables).

### Changed

- [#1284](https://github.com/thanos-io/thanos/pull/1284) Add support for multiple label-sets in Info gRPC service.
  This deprecates the single `Labels` slice of the `InfoResponse`, in a future release backward compatible handling for the single set of Labels will be removed. Upgrading to v0.6.0 or higher is advised.
  _breaking_ If you run have duplicate queries in your Querier configuration with hierarchical federation of multiple Queries this PR makes Thanos Querier to detect this case and block all duplicates. Refer to 0.6.1 which at least allows for single replica to work.

- [#1314](https://github.com/thanos-io/thanos/pull/1314) Removes `http_request_duration_microseconds` (Summary) and adds `http_request_duration_seconds` (Histogram) from http server instrumentation used in Thanos APIs and UIs.

- [#1287](https://github.com/thanos-io/thanos/pull/1287) Sidecar now waits on Prometheus' external labels before starting the uploading process

- [#1261](https://github.com/thanos-io/thanos/pull/1261) Thanos Receive now exposes metrics `thanos_http_request_duration_seconds` and `thanos_http_response_size_bytes` properly of each handler

- [#1274](https://github.com/thanos-io/thanos/pull/1274) Iteration limit has been lifted from the LRU cache so there should be no more spam of error messages as they were harmless

- [#1321](https://github.com/thanos-io/thanos/pull/1321) Thanos Query now fails early on a query which only uses external labels - this improves clarity in certain situations

### Fixed

- [#1227](https://github.com/thanos-io/thanos/pull/1227) Some context handling issues were fixed in Thanos Compact; some unnecessary memory allocations were removed in the hot path of Thanos Store.

- [#1183](https://github.com/thanos-io/thanos/pull/1183) Compactor now correctly propagates retriable/haltable errors which means that it will not unnecessarily restart if such an error occurs

- [#1231](https://github.com/thanos-io/thanos/pull/1231) Receive now correctly handles SIGINT and closes without deadlocking

- [#1278](https://github.com/thanos-io/thanos/pull/1278) Fixed inflated values problem with `sum()` on Thanos Query

- [#1280](https://github.com/thanos-io/thanos/pull/1280) Fixed a problem with concurrent writes to a `map` in Thanos Query while rendering the UI

- [#1311](https://github.com/thanos-io/thanos/pull/1311) Fixed occasional panics in Compact and Store when using Azure Blob cloud storage caused by lack of error checking in client library.

- [#1322](https://github.com/thanos-io/thanos/pull/1322) Removed duplicated closing of the gRPC listener - this gets rid of harmless messages like `store gRPC listener: close tcp 0.0.0.0:10901: use of closed network connection` when those programs are being closed

### Deprecated

- [#1216](https://github.com/thanos-io/thanos/pull/1216) the old "Command-line flags" has been removed from Thanos Query UI since it was not populated and because we are striving for consistency

## [v0.5.0](https://github.com/thanos-io/thanos/releases/tag/v0.5.0) - 2019.06.05

TL;DR: Store LRU cache is no longer leaking, Upgraded Thanos UI to Prometheus 2.9, Fixed auto-downsampling, Moved to Go 1.12.5 and more.

This version moved tarballs to Golang 1.12.5 from 1.11 as well, so same warning applies if you use `container_memory_usage_bytes` from cadvisor. Use `container_memory_working_set_bytes` instead.

_breaking_ As announced couple of times this release also removes gossip with all configuration flags (`--cluster.*`).

### Fixed

- [#1142](https://github.com/thanos-io/thanos/pull/1142) fixed major leak on store LRU cache for index items (postings and series).
- [#1163](https://github.com/thanos-io/thanos/pull/1163) sidecar is no longer blocking for custom Prometheus versions/builds. It only checks if flags return non 404, then it performs optional checks.
- [#1146](https://github.com/thanos-io/thanos/pull/1146) store/bucket: make getFor() work with interleaved resolutions.
- [#1157](https://github.com/thanos-io/thanos/pull/1157) querier correctly handles duplicated stores when some store changes external labels in place.

### Added

- [#1094](https://github.com/thanos-io/thanos/pull/1094) Allow configuring the response header timeout for the S3 client.

### Changed

- [#1118](https://github.com/thanos-io/thanos/pull/1118) _breaking_ swift: Added support for cross-domain authentication by introducing `userDomainID`, `userDomainName`, `projectDomainID`, `projectDomainName`.
  The outdated terms `tenantID`, `tenantName` are deprecated and have been replaced by `projectID`, `projectName`.

- [#1066](https://github.com/thanos-io/thanos/pull/1066) Upgrade Thanos ui to Prometheus v2.9.1.

  Changes from the upstream:

  - query:
    - [ENHANCEMENT] Update moment.js and moment-timezone.js [PR #4679](https://github.com/prometheus/prometheus/pull/4679)
    - [ENHANCEMENT] Support to query elements by a specific time [PR #4764](https://github.com/prometheus/prometheus/pull/4764)
    - [ENHANCEMENT] Update to Bootstrap 4.1.3 [PR #5192](https://github.com/prometheus/prometheus/pull/5192)
    - [BUGFIX] Limit number of merics in prometheus UI [PR #5139](https://github.com/prometheus/prometheus/pull/5139)
    - [BUGFIX] Web interface Quality of Life improvements [PR #5201](https://github.com/prometheus/prometheus/pull/5201)
  - rule:
    - [ENHANCEMENT] Improve rule views by wrapping lines [PR #4702](https://github.com/prometheus/prometheus/pull/4702)
    - [ENHANCEMENT] Show rule evaluation errors on rules page [PR #4457](https://github.com/prometheus/prometheus/pull/4457)

- [#1156](https://github.com/thanos-io/thanos/pull/1156) Moved CI and docker multistage to Golang 1.12.5 for latest mem alloc improvements.
- [#1103](https://github.com/thanos-io/thanos/pull/1103) Updated go-cos deps. (COS bucket client).
- [#1149](https://github.com/thanos-io/thanos/pull/1149) Updated google Golang API deps (GCS bucket client).
- [#1190](https://github.com/thanos-io/thanos/pull/1190) Updated minio deps (S3 bucket client). This fixes minio retries.

- [#1133](https://github.com/thanos-io/thanos/pull/1133) Use prometheus v2.9.2, common v0.4.0 & tsdb v0.8.0.

  Changes from the upstreams:

  - store gateway:
    - [ENHANCEMENT] Fast path for EmptyPostings cases in Merge, Intersect and Without.
  - store gateway & compactor:
    - [BUGFIX] Fix fd and vm_area leak on error path in chunks.NewDirReader.
    - [BUGFIX] Fix fd and vm_area leak on error path in index.NewFileReader.
  - query:
    - [BUGFIX] Make sure subquery range is taken into account for selection #5467
    - [ENHANCEMENT] Check for cancellation on every step of a range evaluation. #5131
    - [BUGFIX] Exponentation operator to drop metric name in result of operation. #5329
    - [BUGFIX] Fix output sample values for scalar-to-vector comparison operations. #5454
  - rule:
    - [BUGFIX] Reload rules: copy state on both name and labels. #5368

## Deprecated

- [#1008](https://github.com/thanos-io/thanos/pull/1008) _breaking_ Removed Gossip implementation. All `--cluster.*` flags removed and Thanos will error out if any is provided.

## [v0.4.0](https://github.com/thanos-io/thanos/releases/tag/v0.4.0) - 2019.05.3

:warning: **IMPORTANT** :warning: This is the last release that supports gossip. From Thanos v0.5.0, gossip will be completely removed.

This release also disables gossip mode by default for all components.
See [this](docs/proposals/201809_gossip-removal.md) for more details.

:warning: This release moves Thanos docker images (NOT artifacts by accident) to Golang 1.12. This release includes change in GC's memory release which gives following effect:

> On Linux, the runtime now uses MADV_FREE to release unused memory. This is more efficient but may result in higher reported RSS. The kernel will reclaim the unused data when it is needed. To revert to the Go 1.11 behavior (MADV_DONTNEED), set the environment variable GODEBUG=madvdontneed=1.

If you want to see exact memory allocation of Thanos process:

- Use `go_memstats_heap_alloc_bytes` metric exposed by Golang or `container_memory_working_set_bytes` exposed by cadvisor.
- Add `GODEBUG=madvdontneed=1` before running Thanos binary to revert to memory releasing to pre 1.12 logic.

Using cadvisor `container_memory_usage_bytes` metric could be misleading e.g: https://github.com/google/cadvisor/issues/2242

### Added

- [thanos.io](https://thanos.io) website & automation :tada:
- [#1053](https://github.com/thanos-io/thanos/pull/1053) compactor: Compactor & store gateway now handles incomplete uploads gracefully. Added hard limit on how long block upload can take (30m).
- [#811](https://github.com/thanos-io/thanos/pull/811) Remote write receiver component :heart: :heart: thanks to RedHat (@brancz) contribution.
- [#910](https://github.com/thanos-io/thanos/pull/910) Query's stores UI page is now sorted by type and old DNS or File SD stores are removed after 5 minutes (configurable via the new `--store.unhealthy-timeout=5m` flag).
- [#905](https://github.com/thanos-io/thanos/pull/905) Thanos support for Query API: /api/v1/labels. Notice that the API was added in Prometheus v2.6.
- [#798](https://github.com/thanos-io/thanos/pull/798) Ability to limit the maximum number of concurrent request to Series() calls in Thanos Store and the maximum amount of samples we handle.
- [#1060](https://github.com/thanos-io/thanos/pull/1060) Allow specifying region attribute in S3 storage configuration

:warning: **WARNING** :warning: #798 adds a new default limit to Thanos Store: `--store.grpc.series-max-concurrency`. Most likely you will want to make it the same as `--query.max-concurrent` on Thanos Query.

New options:

New Store flags:

    * `--store.grpc.series-sample-limit` limits the amount of samples that might be retrieved on a single Series() call. By default it is 0. Consider enabling it by setting it to more than 0 if you are running on limited resources.
    * `--store.grpc.series-max-concurrency` limits the number of concurrent Series() calls in Thanos Store. By default it is 20. Considering making it lower or bigger depending on the scale of your deployment.

New Store metrics:

    * `thanos_bucket_store_queries_dropped_total` shows how many queries were dropped due to the samples limit;
    * `thanos_bucket_store_queries_concurrent_max` is a constant metric which shows how many Series() calls can concurrently be executed by Thanos Store;
    * `thanos_bucket_store_queries_in_flight` shows how many queries are currently "in flight" i.e. they are being executed;
    * `thanos_bucket_store_gate_duration_seconds` shows how many seconds it took for queries to pass through the gate in both cases - when that fails and when it does not.

New Store tracing span: \* `store_query_gate_ismyturn` shows how long it took for a query to pass (or not) through the gate.

- [#1016](https://github.com/thanos-io/thanos/pull/1016) Added option for another DNS resolver (miekg/dns client).
  Note that this is required to have SRV resolution working on [Golang 1.11+ with KubeDNS below v1.14](https://github.com/golang/go/issues/27546)

  New Querier and Ruler flag: `-- store.sd-dns-resolver` which allows to specify resolver to use. Either `golang` or `miekgdns`

- [#986](https://github.com/thanos-io/thanos/pull/986) Allow to save some startup & sync time in store gateway as it is no longer needed to compute index-cache from block index on its own for larger blocks.
  The store Gateway still can do it, but it first checks bucket if there is index-cached uploaded already.
  In the same time, compactor precomputes the index cache file on every compaction.

  New Compactor flag: `--index.generate-missing-cache-file` was added to allow quicker addition of index cache files. If enabled it precomputes missing files on compactor startup. Note that it will take time and it's only one-off step per bucket.

- [#887](https://github.com/thanos-io/thanos/pull/887) Compact: Added new `--block-sync-concurrency` flag, which allows you to configure number of goroutines to use when syncing block metadata from object storage.
- [#928](https://github.com/thanos-io/thanos/pull/928) Query: Added `--store.response-timeout` flag. If a Store doesn't send any data in this specified duration then a Store will be ignored and partial data will be returned if it's enabled. 0 disables timeout.
- [#893](https://github.com/thanos-io/thanos/pull/893) S3 storage backend has graduated to `stable` maturity level.
- [#936](https://github.com/thanos-io/thanos/pull/936) Azure storage backend has graduated to `stable` maturity level.
- [#937](https://github.com/thanos-io/thanos/pull/937) S3: added trace functionality. You can add `trace.enable: true` to enable the minio client's verbose logging.
- [#953](https://github.com/thanos-io/thanos/pull/953) Compact: now has a hidden flag `--debug.accept-malformed-index`. Compaction index verification will ignore out of order label names.
- [#963](https://github.com/thanos-io/thanos/pull/963) GCS: added possibility to inline ServiceAccount into GCS config.
- [#1010](https://github.com/thanos-io/thanos/pull/1010) Compact: added new flag `--compact.concurrency`. Number of goroutines to use when compacting groups.
- [#1028](https://github.com/thanos-io/thanos/pull/1028) Query: added `--query.default-evaluation-interval`, which sets default evaluation interval for sub queries.
- [#980](https://github.com/thanos-io/thanos/pull/980) Ability to override Azure storage endpoint for other regions (China)
- [#1021](https://github.com/thanos-io/thanos/pull/1021) Query API `series` now supports POST method.
- [#939](https://github.com/thanos-io/thanos/pull/939) Query API `query_range` now supports POST method.

### Changed

- [#970](https://github.com/thanos-io/thanos/pull/970) Deprecated `partial_response_disabled` proto field. Added `partial_response_strategy` instead. Both in gRPC and Query API.
  No `PartialResponseStrategy` field for `RuleGroups` by default means `abort` strategy (old PartialResponse disabled) as this is recommended option for Rules and alerts.

  Metrics:

  - Added `thanos_rule_evaluation_with_warnings_total` to Ruler.
  - DNS `thanos_ruler_query_apis*` are now `thanos_ruler_query_apis_*` for consistency.
  - DNS `thanos_querier_store_apis*` are now `thanos_querier_store_apis__*` for consistency.
  - Query Gate `thanos_bucket_store_series*` are now `thanos_bucket_store_series_*` for consistency.
  - Most of thanos ruler metris related to rule manager has `strategy` label.

  Ruler tracing spans:

  - `/rule_instant_query HTTP[client]` is now `/rule_instant_query_part_resp_abort HTTP[client]"` if request is for abort strategy.

- [#1009](https://github.com/thanos-io/thanos/pull/1009): Upgraded Prometheus (~v2.7.0-rc.0 to v2.8.1) and TSDB (`v0.4.0` to `v0.6.1`) deps.

  Changes that affects Thanos:

  - query:
    - [ENHANCEMENT] In histogram_quantile merge buckets with equivalent le values. #5158.
    - [ENHANCEMENT] Show list of offending labels in the error message in many-to-many scenarios. #5189
    - [BUGFIX] Fix panic when aggregator param is not a literal. #5290
  - ruler:
    - [ENHANCEMENT] Reduce time that Alertmanagers are in flux when reloaded. #5126
    - [BUGFIX] prometheus_rule_group_last_evaluation_timestamp_seconds is now a unix timestamp. #5186
    - [BUGFIX] prometheus_rule_group_last_duration_seconds now reports seconds instead of nanoseconds. Fixes our [issue #1027](https://github.com/thanos-io/thanos/issues/1027)
    - [BUGFIX] Fix sorting of rule groups. #5260
  - store: [ENHANCEMENT] Fast path for EmptyPostings cases in Merge, Intersect and Without.
  - tooling: [FEATURE] New dump command to tsdb tool to dump all samples.
  - compactor:
    - [ENHANCEMENT] When closing the db any running compaction will be cancelled so it doesn't block.
    - [CHANGE] _breaking_ Renamed flag `--sync-delay` to `--consistency-delay` [#1053](https://github.com/thanos-io/thanos/pull/1053)

  For ruler essentially whole TSDB CHANGELOG applies between v0.4.0-v0.6.1: https://github.com/prometheus/tsdb/blob/master/CHANGELOG.md

  Note that this was added on TSDB and Prometheus: [FEATURE] Time-ovelapping blocks are now allowed. #370
  Whoever due to nature of Thanos compaction (distributed systems), for safety reason this is disabled for Thanos compactor for now.

- [#868](https://github.com/thanos-io/thanos/pull/868) Go has been updated to 1.12.
- [#1055](https://github.com/thanos-io/thanos/pull/1055) Gossip flags are now disabled by default and deprecated.
- [#964](https://github.com/thanos-io/thanos/pull/964) repair: Repair process now sorts the series and labels within block.
- [#1073](https://github.com/thanos-io/thanos/pull/1073) Store: index cache for requests. It now calculates the size properly (includes slice header), has anti-deadlock safeguard and reports more metrics.

### Fixed

- [#921](https://github.com/thanos-io/thanos/pull/921) `thanos_objstore_bucket_last_successful_upload_time` now does not appear when no blocks have been uploaded so far.
- [#966](https://github.com/thanos-io/thanos/pull/966) Bucket: verify no longer warns about overlapping blocks, that overlap `0s`
- [#848](https://github.com/thanos-io/thanos/pull/848) Compact: now correctly works with time series with duplicate labels.
- [#894](https://github.com/thanos-io/thanos/pull/894) Thanos Rule: UI now correctly shows evaluation time.
- [#865](https://github.com/thanos-io/thanos/pull/865) Query: now properly parses DNS SRV Service Discovery.
- [#889](https://github.com/thanos-io/thanos/pull/889) Store: added safeguard against merging posting groups segfault
- [#941](https://github.com/thanos-io/thanos/pull/941) Sidecar: added better handling of intermediate restarts.
- [#933](https://github.com/thanos-io/thanos/pull/933) Query: Fixed 30 seconds lag of adding new store to query.
- [#962](https://github.com/thanos-io/thanos/pull/962) Sidecar: Make config reloader file writes atomic.
- [#982](https://github.com/thanos-io/thanos/pull/982) Query: now advertises Min & Max Time accordingly to the nodes.
- [#1041](https://github.com/thanos-io/thanos/issues/1038) Ruler is now able to return long time range queries.
- [#904](https://github.com/thanos-io/thanos/pull/904) Compact: Skip compaction for blocks with no samples.
- [#1070](https://github.com/thanos-io/thanos/pull/1070) Downsampling works back again. Deferred closer errors are now properly captured.

## [v0.3.2](https://github.com/thanos-io/thanos/releases/tag/v0.3.2) - 2019.03.04

### Added

- [#851](https://github.com/thanos-io/thanos/pull/851) New read API endpoint for api/v1/rules and api/v1/alerts.
- [#873](https://github.com/thanos-io/thanos/pull/873) Store: fix set index cache LRU

:warning: **WARNING** :warning: #873 fix fixes actual handling of `index-cache-size`. Handling of limit for this cache was
broken so it was unbounded all the time. From this release actual value matters and is extremely low by default. To "revert"
the old behaviour (no boundary), use a large enough value.

### Fixed

- [#833](https://github.com/thanos-io/thanos/issues/833) Store Gateway matcher regression for intersecting with empty posting.
- [#867](https://github.com/thanos-io/thanos/pull/867) Fixed race condition in sidecare between reloader and shipper.

## [v0.3.1](https://github.com/thanos-io/thanos/releases/tag/v0.3.1) - 2019.02.18

### Fixed

- [#829](https://github.com/thanos-io/thanos/issues/829) Store Gateway crashing due to `slice bounds out of range`.
- [#834](https://github.com/thanos-io/thanos/issues/834) Store Gateway matcher regression for `<>` `!=`.

## [v0.3.0](https://github.com/thanos-io/thanos/releases/tag/v0.3.0) - 2019.02.08

### Added

- Support for gzip compressed configuration files before envvar substitution for reloader package.
- `bucket inspect` command for better insights on blocks in object storage.
- Support for [Tencent COS](docs/storage.md#tencent-cos-configuration) object storage.
- Partial Response disable option for StoreAPI and QueryAPI.
- Partial Response disable button on Thanos UI
- We have initial docs for goDoc documentation!
- Flags for Querier and Ruler UIs: `--web.route-prefix`, `--web.external-prefix`, `--web.prefix-header`. Details [here](docs/components/query.md#expose-ui-on-a-sub-path)

### Fixed

- [#649](https://github.com/thanos-io/thanos/issues/649) - Fixed store label values api to add also external label values.
- [#396](https://github.com/thanos-io/thanos/issues/396) - Fixed sidecar logic for proxying series that has more than 2^16 samples from Prometheus.
- [#732](https://github.com/thanos-io/thanos/pull/732) - Fixed S3 authentication sequence. You can see new sequence enumerated [here](https://github.com/thanos-io/thanos/blob/master/docs/storage.md#aws-s3-configuration)
- [#745](https://github.com/thanos-io/thanos/pull/745) - Fixed race conditions and edge cases for Thanos Querier fanout logic.
- [#651](https://github.com/thanos-io/thanos/issues/651) - Fixed index cache when asked buffer size is bigger than cache max size.

### Changed

- [#529](https://github.com/thanos-io/thanos/pull/529) Massive improvement for compactor. Downsampling memory consumption was reduce to only store labels and single chunks per each series.
- Qurerier UI: Store page now shows the store APIs per component type.
- Prometheus and TSDB deps are now up to date with ~2.7.0 Prometheus version. Lot's of things has changed. See details [here #704](https://github.com/thanos-io/thanos/pull/704) Known changes that affects us:
  - prometheus/prometheus/discovery/file
    - [ENHANCEMENT] Discovery: Improve performance of previously slow updates of changes of targets. #4526
    - [BUGFIX] Wait for service discovery to stop before exiting #4508 ??
  - prometheus/prometheus/promql:
    - **[ENHANCEMENT] Subqueries support. #4831**
    - [BUGFIX] PromQL: Fix a goroutine leak in the lexer/parser. #4858
    - [BUGFIX] Change max/min over_time to handle NaNs properly. #438
    - [BUGFIX] Check label name for `count_values` PromQL function. #4585
    - [BUGFIX] Ensure that vectors and matrices do not contain identical label-sets. #4589
    - [ENHANCEMENT] Optimize PromQL aggregations #4248
    - [BUGFIX] Only add LookbackDelta to vector selectors #4399
    - [BUGFIX] Reduce floating point errors in stddev and related functions #4533
  - prometheus/prometheus/rules:
    - New metrics exposed! (prometheus evaluation!)
    - [ENHANCEMENT] Rules: Error out at load time for invalid templates, rather than at evaluation time. #4537
  - prometheus/tsdb/index: Index reader optimizations.
- Thanos store gateway flag for sync concurrency (`block-sync-concurrency` with `20` default, so no change by default)
- S3 provider:
  - Added `put_user_metadata` option to config.
  - Added `insecure_skip_verify` option to config.

### Deprecated

- Tests against Prometheus below v2.2.1. This does not mean _lack_ of support for those. Only that we don't tests the compatibility anymore. See [#758](https://github.com/thanos-io/thanos/issues/758) for details.

## [v0.2.1](https://github.com/thanos-io/thanos/releases/tag/v0.2.1) - 2018.12.27

### Added

- Relabel drop for Thanos Ruler to enable replica label drop and alert deduplication on AM side.
- Query: Stores UI page available at `/stores`.

![](./docs/img/query_ui_stores.png)

### Fixed

- Thanos Rule Alertmanager DNS SD bug.
- DNS SD bug when having SRV results with different ports.
- Move handling of HA alertmanagers to be the same as Prometheus.
- Azure iteration implementation flaw.

## [v0.2.0](https://github.com/thanos-io/thanos/releases/tag/v0.2.0) - 2018.12.10

Next Thanos release adding support to new discovery method, gRPC mTLS and two new object store providers (Swift and Azure).

Note lots of necessary breaking changes in flags that relates to bucket configuration.

### Deprecated

- _breaking_: Removed all bucket specific flags as we moved to config files:
  - --gcs-bucket=\<bucket\>
  - --s3.bucket=\<bucket\>
  - --s3.endpoint=\<api-url\>
  - --s3.access-key=\<key\>
  - --s3.insecure
  - --s3.signature-version2
  - --s3.encrypt-sse
  - --gcs-backup-bucket=\<bucket\>
  - --s3-backup-bucket=\<bucket\>
- _breaking_: Removed support of those environment variables for bucket:
  - S3_BUCKET
  - S3_ENDPOINT
  - S3_ACCESS_KEY
  - S3_INSECURE
  - S3_SIGNATURE_VERSION2
- _breaking_: Removed provider specific bucket metrics e.g `thanos_objstore_gcs_bucket_operations_total` in favor of of generic bucket operation metrics.

### Changed

- _breaking_: Added `thanos_` prefix to memberlist (gossip) metrics. Make sure to update your dashboards and rules.
- S3 provider:
  - Set `"X-Amz-Acl": "bucket-owner-full-control"` metadata for s3 upload operation.

### Added

- Support for heterogeneous secure gRPC on StoreAPI.
- Handling of scalar result in rule node evaluating rules.
- Flag `--objstore.config-file` to reference to the bucket configuration file in yaml format. Detailed information can be found in document [storage](docs/storage.md).
- File service discovery for StoreAPIs:
- In `thanos rule`, static configuration of query nodes via `--query`
- In `thanos rule`, file based discovery of query nodes using `--query.file-sd-config.files`
- In `thanos query`, file based discovery of store nodes using `--store.file-sd-config.files`
- `/-/healthy` endpoint to Querier.
- DNS service discovery to static and file based configurations using the `dns+` and `dnssrv+` prefixes for the respective lookup. Details [here](docs/service-discovery.md)
- `--cluster.disable` flag to disable gossip functionality completely.
- Hidden flag to configure max compaction level.
- Azure Storage.
- OpenStack Swift support.
- Thanos Ruler `thanos_rule_loaded_rules` metric.
- Option for JSON logger format.

### Fixed

- Issue whereby the Proxy Store could end up in a deadlock if there were more than 9 stores being queried and all returned an error.
- Ruler tracing causing panics.
- GatherIndexStats panics on duplicated chunks check.
- Clean up of old compact blocks on compact restart.
- Sidecar too frequent Prometheus reload.
- `thanos_compactor_retries_total` metric not being registered.

## [v0.1.0](https://github.com/thanos-io/thanos/releases/tag/v0.1.0) - 2018.09.14

Initial version to have a stable reference before [gossip protocol removal](/docs/proposals/201809_gossip-removal.md).

### Added

- Gossip layer for all components.
- StoreAPI gRPC proto.
- TSDB block upload logic for Sidecar.
- StoreAPI logic for Sidecar.
- Config and rule reloader logic for Sidecar.
- On-the fly result merge and deduplication logic for Querier.
- Custom Thanos UI (based mainly on Prometheus UI) for Querier.
- Optimized object storage fetch logic for Store.
- Index cache and chunk pool for Store for better memory usage.
- Stable support for Google Cloud Storage object storage.
- StoreAPI logic for Querier to support Thanos federation (experimental).
- Support for S3 minio-based AWS object storage (experimental).
- Compaction logic of blocks from multiple sources for Compactor.
- Optional Compaction fixed retention.
- Optional downsampling logic for Compactor (experimental).
- Rule (including alerts) evaluation logic for Ruler.
- Rule UI with hot rules reload.
- StoreAPI logic for Ruler.
- Basic metric orchestration for all components.
- Verify commands with potential fixes (experimental).
- Compact / Downsample offline commands.
- Bucket commands.
- Downsampling support for UI.
- Grafana dashboards for Thanos components.
