Release notes from prometheus

3.10.0 / 2026-02-24

2026-02-26T01:19:52Z

Prometheus now offers a distroless Docker image variant alongside the default
busybox image. The distroless variant provides enhanced security with a minimal
base image, uses UID/GID 65532 (nonroot) instead of nobody, and removes the
VOLUME declaration. Both variants are available with -busybox and -distroless
tag suffixes (e.g., prom/prometheus:latest-busybox, prom/prometheus:latest-distroless).
The busybox image remains the default with no suffix for backwards compatibility
(e.g., prom/prometheus:latest points to the busybox variant).

For users migrating existing named volumes from the busybox image to the distroless variant, the ownership can be adjusted with:

docker run --rm -v prometheus-data:/prometheus alpine chown -R 65532:65532 /prometheus

Then, the container can be started with the old volume with:

docker run -v prometheus-data:/prometheus prom/prometheus:latest-distroless

User migrating from bind mounts might need to ajust permissions too, depending on their setup.

[CHANGE] Alerting: Add alertmanager dimension to following metrics: prometheus_notifications_dropped_total, prometheus_notifications_queue_capacity, prometheus_notifications_queue_length. #16355
[CHANGE] UI: Hide expanded alert annotations by default, enabling more information density on the /alerts page. #17611
[FEATURE] AWS SD: Add MSK Role. #17600
[FEATURE] PromQL: Add fill() / fill_left() / fill_right() binop modifiers for specifying default values for missing series. #17644
[FEATURE] Web: Add OpenAPI 3.2 specification for the HTTP API at /api/v1/openapi.yaml. #17825
[FEATURE] Dockerfile: Add distroless image variant using UID/GID 65532 and no VOLUME declaration. Busybox image remains default. #17876
[FEATURE] Web: Add on-demand wall time profiling under <URL>/debug/pprof/fgprof. #18027
[ENHANCEMENT] PromQL: Add more detail to histogram quantile monotonicity info annotations. #15578
[ENHANCEMENT] Alerting: Independent alertmanager sendloops. #16355
[ENHANCEMENT] TSDB: Experimental support for early compaction of stale series in the memory with configurable threshold stale_series_compaction_threshold in the config file. #16929
[ENHANCEMENT] Service Discovery: Service discoveries are now removable from the Prometheus binary through the Go build tag remove_all_sd and individual service discoveries can be re-added with the build tags enable_<sd name>_sd. Users can build a custom Prometheus with only the necessary SDs for a smaller binary size. #17736
[ENHANCEMENT] Promtool: Support promql syntax features promql-duration-expr and promql-extended-range-selectors. #17926
[PERF] PromQL: Avoid unnecessary label extraction in PromQL functions. #17676
[PERF] PromQL: Improve performance of regex matchers like .*-.*-.*. #17707
[PERF] OTLP: Add label caching for OTLP-to-Prometheus conversion to reduce allocations and improve latency. #17860
[PERF] API: Compute /api/v1/targets/relabel_steps in a single pass instead of re-running relabeling for each prefix. #17969
[PERF] tsdb: Optimize LabelValues intersection performance for matchers. #18069
[BUGFIX] PromQL: Prevent query strings containing only UTF-8 continuation bytes from crashing Prometheus. #17735
[BUGFIX] Web: Fix missing X-Prometheus-Stopping header for /-/ready endpoint in NotReady state. #17795
[BUGFIX] PromQL: Fix PromQL info() function returning empty results when filtering by a label that exists on both the input metric and target_info. #17817
[BUGFIX] TSDB: Fix a bug during exemplar buffer grow/shrink that could cause exemplars to be incorrectly discarded. #17863
[BUGFIX] UI: Fix broken graph display after page reload, due to broken Y axis min encoding/decoding. #17869
[BUGFIX] TSDB: Fix memory leaks in buffer pools by clearing reference fields (Labels, Histogram pointers, metadata strings) before returning buffers to pools. #17879
[BUGFIX] PromQL: info function: fix series without identifying labels not being returned. #17898
[BUGFIX] OTLP: Filter __name__ from OTLP attributes to prevent duplicate labels. #17917
[BUGFIX] TSDB: Fix division by zero when computing stale series ratio with empty head. #17952
[BUGFIX] OTLP: Fix potential silent data loss for sum metrics. #17954
[BUGFIX] PromQL: Fix smoothed interpolation across counter resets. #17988
[BUGFIX] PromQL: Fix panic with @ modifier on empty ranges. #18020
[BUGFIX] PromQL: Fix avg_over_time for a single native histogram. #18058

v0.310.0

2026-02-25T21:10:18Z

v0.310.0

3.10.0-rc.1 / 2026-02-19

2026-02-20T00:59:30Z

For users migrating existing named volumes from the busybox image to the distroless variant, the ownership can be adjusted with:

docker run --rm -v prometheus-data:/prometheus alpine chown -R 65532:65532 /prometheus

Then, the container can be started with the old volume with:

docker run -v prometheus-data:/prometheus prom/prometheus:latest-distroless

User migrating from bind mounts might need to ajust permissions too, depending on their setup.

[CHANGE] Alerting: Add alertmanager dimension to following metrics: prometheus_notifications_dropped_total, prometheus_notifications_queue_capacity, prometheus_notifications_queue_length. #16355
[CHANGE] UI: Hide expanded alert annotations by default, enabling more information density on the /alerts page. #17611
[FEATURE] AWS SD: Add MSK Role. #17600
[FEATURE] PromQL: Add fill() / fill_left() / fill_right() binop modifiers for specifying default values for missing series. #17644
[FEATURE] Web: Add OpenAPI 3.2 specification for the HTTP API at /api/v1/openapi.yaml. #17825
[FEATURE] Dockerfile: Add distroless image variant using UID/GID 65532 and no VOLUME declaration. Busybox image remains default. #17876
[FEATURE] Web: Add on-demand wall time profiling under <URL>/debug/pprof/fgprof. #18027
[ENHANCEMENT] PromQL: Add more detail to histogram quantile monotonicity info annotations. #15578
[ENHANCEMENT] Alerting: Independent alertmanager sendloops. #16355
[ENHANCEMENT] TSDB: Experimental support for early compaction of stale series in the memory with configurable threshold stale_series_compaction_threshold in the config file. #16929
[ENHANCEMENT] Service Discovery: Service discoveries are now removable from the Prometheus binary through the Go build tag remove_all_sd and individual service discoveries can be re-added with the build tags enable_<sd name>_sd. Users can build a custom Prometheus with only the necessary SDs for a smaller binary size. #17736
[ENHANCEMENT] Promtool: Support promql syntax features promql-duration-expr and promql-extended-range-selectors. #17926
[PERF] PromQL: Avoid unnecessary label extraction in PromQL functions. #17676
[PERF] PromQL: Improve performance of regex matchers like .*-.*-.*. #17707
[PERF] OTLP: Add label caching for OTLP-to-Prometheus conversion to reduce allocations and improve latency. #17860
[PERF] API: Compute /api/v1/targets/relabel_steps in a single pass instead of re-running relabeling for each prefix. #17969
[PERF] tsdb: Optimize LabelValues intersection performance for matchers. #18069
[BUGFIX] PromQL: Prevent query strings containing only UTF-8 continuation bytes from crashing Prometheus. #17735
[BUGFIX] Web: Fix missing X-Prometheus-Stopping header for /-/ready endpoint in NotReady state. #17795
[BUGFIX] PromQL: Fix PromQL info() function returning empty results when filtering by a label that exists on both the input metric and target_info. #17817
[BUGFIX] TSDB: Fix a bug during exemplar buffer grow/shrink that could cause exemplars to be incorrectly discarded. #17863
[BUGFIX] UI: Fix broken graph display after page reload, due to broken Y axis min encoding/decoding. #17869
[BUGFIX] TSDB: Fix memory leaks in buffer pools by clearing reference fields (Labels, Histogram pointers, metadata strings) before returning buffers to pools. #17879
[BUGFIX] PromQL: info function: fix series without identifying labels not being returned. #17898
[BUGFIX] OTLP: Filter __name__ from OTLP attributes to prevent duplicate labels. #17917
[BUGFIX] TSDB: Fix division by zero when computing stale series ratio with empty head. #17952
[BUGFIX] OTLP: Fix potential silent data loss for sum metrics. #17954
[BUGFIX] PromQL: Fix smoothed interpolation across counter resets. #17988
[BUGFIX] PromQL: Fix panic with @ modifier on empty ranges. #18020
[BUGFIX] PromQL: Fix avg_over_time for a single native histogram. #18058

v0.310.0-rc.1

2026-02-19T23:54:36Z

v0.310.0-rc.1

v3.10.0-rc.0

2026-02-18T00:11:18Z

v3.10.0-rc.0

v0.310.0-rc.0

2026-02-18T00:13:04Z

v0.310.0-rc.0

3.5.1 / 2026-01-07

2026-01-22T13:50:29Z

This is the current "Long Term Support" release.
No code changes since 3.5.0, just some dependency updates:

Docker library updated from 28.2.2 to 28.5.2. #17821
Built with Go 1.24.11.

v0.305.1

2026-01-21T13:29:19Z

v0.305.1

3.9.1 / 2026-01-07

2026-01-07T17:05:54Z

[BUGFIX] Agent: fix crash shortly after startup from invalid type of object. #17802
[BUGFIX] Scraping: fix relabel keep/drop not working. #17807

v0.309.1

2026-01-07T19:20:52Z

v0.309.1