Release notes from clickhouse-operator

release-0.26.1

2026-03-13T13:07:46Z

Fixed

Fixed Keeper startup that was slow due to missing quorum. Closes #1931 and #1856
Fixed Keeper deletion logic that could previously leave PVCs undeleted
Fixed hostName generation in status that might result in excessive schema propagation cycles
Fixed FQDN normalization to prevent trailing-dot inconsistencies between internal hostname representations
Bump stdlib version to address CVE
Bump base image version by @Slach in #1941. Closes #1940
Document custom service template behaviour for CHK by @realyota in #1939

Full Changelog: release-0.26.0...release-0.26.1

untagged-4ee52d216bcc11b71c61

2026-02-20T13:16:09Z

env: operatohub manifests

release-0.26.0

2026-02-20T13:27:56Z

IMPORTANT: Due to ClickHouse upstream regression ClickHouse/ClickHouse#89693 DDL queries may not work on newly created ClickHouse pods. It affects Kubernetes deployments only in some new ClickHouse versions (25.8.10+ and above). The workaround is to restart ClickHouse pods. The problem is fixed by ClickHouse/ClickHouse#92339, see backports for different release branches. The fix is backported to Altinity Stable 25.8.16.10001 as well.
Closes #1883 and #1913

Added

Added an option to abort reconcile if STS needs to be recreated. It can be configured in operator configuration or CHI.

# Reconcile StatefulSet scenario
reconcile:
  statefulSet:
    recreate:
      # What to do in case operator is in need to recreate StatefulSet?
      # Possible options:
      # 1. abort - abort the process, do nothing with the problematic StatefulSet, leave it as it is,
      #    do not try to fix or delete or update it, just abort reconcile cycle.
      #    Do not proceed to the next StatefulSet(s) and wait for an admin to assist.
      # 2. recreate - proceed and recreate StatefulSet.
      # Triggered when StatefulSet update fails or StatefulSet is not ready
      onUpdateFailure: recreate

Added an option to configure system tables for metrics scrapping. The default is system.metrics and system.custom_metrics tables, but those can be changed with a regular expression if needed:

    tablesRegexp: "^(metrics|custom_metrics)$"

Changed

The suspend flag now immediately aborts a running reconcile. Previously, it did not affect the one that was running
When suspend flag is set, any reconcile attempt automatically sets CHI/CHK status to aborted.
Add optional registry prefix for operator and metrics images in Helm chart by @lesandie in #1928
Improve ClickHouse Keeper Grafana Dashboard by @discostur in #1872
Add CRDHook annotations by @eyyu in #1914
Hotfix crdhook, add imagePullSecrets by @Slach in #1917
Fix installer to default template URL to OPERATOR_VERSION by @realyota in #1910
sort keys in Settings.Keys() method for consistent order (fix manifest reconcile issue) by @mastercactapus in #1900
Multiple documentation fixes

Fixed

Fixed Keeper rolling update logic. Closes #1796 #1915
Fixed a bug when replica was not added to monitoring until it catches up the replication lag
Fixed version parsing for FIPS compatible builds of ClickHouse. Closes #1850
Fixed stop and suspend attributes for CHK that were previously ignored
Fix distributed_ddl.replicas_path mismatch that could prevent sharing (Zoo)Keeper between multiple clusters @Elmo33 in #1922
Fixed a bug when defaults.storageManagement.reclaimPolicy was not respected
Fixed slow initial connectivity to newly created pods caused by DNS search list exhaustion (ndots:5). Added trailing dot to FQDN and increased connect timeout
Fixed a bug where reconcile settings specified at CHI level (e.g. spec.reconcile.statefulSet.recreate.onUpdateFailure) were not inherited by cluster-level reconcile configuration

Other

stdlib has been upgraded to 1.25.6 to address CVEs
Operator has been certified for 25.8.16.10001 Altinity.Stable.

New Contributors

@rajdudhare1 made their first contribution in #1890
@siggy made their first contribution in #1906
@eyyu made their first contribution in #1914
@Elmo33 made their first contribution in #1922
@mastercactapus made their first contribution in #1900
@lesandie made their first contribution in #1928

Full Changelog: release-0.25.6...release-0.26.0

release-0.25.6

2025-12-11T13:44:43Z

Changed

Hosts are not excluded from remote_servers anymore if restart is not needed. Previously, replicas in replicated cluster might be removed for a short time even if restart was not needed.
configuration.zookeeper section changes do not require restart anymore
Last reconciliation error and list of errors are now stored in CHI status

Fixed

actionPlan is now optional in status. That fixes operator upgrade problems that might happen in some environments.
Fixed excessive reconciles triggered by endpoint slices. Closes #1873
Fixed crash in CHK that might happen sometimes. Closes #1863
Fixed an issue with handling fractional requests/limits that would result in excessive reconcile. Closes #1849 #1821
Fixed a bug with operator crash in Terminating namespace. Closes #1871
stdlib was upgraded in order to address CVEs in dependent libraries

NOTE: Due to regression in upstream ClickHouse ClickHouse/ClickHouse#89693 schema propagation and DDL statements do not work with ClickHouse versions 25.8.10+ and newer until it is resolved.

Full Changelog: release-0.25.5...release-0.25.6

release-0.25.5

2025-10-24T09:59:56Z

Added

The latest applied ActionPlan is now stored in chi-storage ConfigMap
volumeClaimTemplate.volumeAttributeClass attribute. Closes #1818
Configuration for DROP REPLICA behavior:

reconcile:
   host:
    drop:
      replicas:
        # Whether the operator during reconcile procedure should drop replicas when replica is deleted
        onDelete: yes
        # Whether the operator during reconcile procedure should drop replicas when replica volume is lost
        onLostVolume: yes
        # Whether the operator during reconcile procedure should drop active replicas when replica is deleted or recreated
        active: no

Now active replicas are never dropped. That solves a potential bug when replica could be dropped on a multi-volume node if newly added volume is not yet available.

Changed

Enabled ReadinessProbe for Keeper. Closes #1846
Enabled query_log for all DDL statements performed by operator
minor logging improvements by @janeklb in #1829

Fixed

Removed excessive logging isUpdatedEndpointSlice():unknown
Changed metrics collection query that could be broken in 0.25.4 for old ClickHouse versions

Helm updates

fix: correctly delete existing helm release artifacts by appending asset ID to URL by @Slach in #1827
Updated Helm repo location to https://helm.altinity.com by @DougTidwell in #1835
Helm: add metrics.enabled conditional checks for serviceMonitor by @KJone1 in #1834
Hotfix helm schema by @Slach in #1842

New Contributors

@KJone1 made their first contribution in #1834
@fkywong made their first contribution in #1837

Full Changelog: release-0.25.4...release-0.25.5

release-0.25.4

2025-09-26T14:58:24Z

Added

Operator configuration 'reconcile' section is now fully supported at CHI level under both 'reconcile' and old 'reconciling' name. Previously, only selected settings were available at CHI level.
Allow to exclude namespaces that operator watches. by @AdheipSingh in #1770

spec:
  watch:
    namespaces:
      include: []
      exclude: [] # new

Option to choose which probe should operator wait for during reconcile. Previously, it always waited for pod to be ready. This can now be configured in 'reconcile' section of operator or CHI:

spec:
  reconcile:
    host:
      wait:
        probes:
          startup: "yes"
          readiness: "no"

ZooKeeper compression support by @wilkermichael in #1809
Support watching multiple namespaces in OLM by @saeedhosseini21 in #1825. Closes #1491

Changed

system.custom_metrics table is currently scrapped for monitoring in addition to metrics and asynchronous_metrics. That allows to inject custom monitoring data from ClickHouse side.
Deprecated Endpoints API has been replaced with EndpointSlice. Closes 1801

Fixed

Fixed a bug with long environment variables used for secrets being truncated. Closes #1804
Fixed a bug that operator did not respect watched namespaces for CHK

Helm updates

Define values.schema.json by @Slach in #1815. Closes #1814
Added clickhouse-operator deployment strategy parameters to Helm chart by @Slach in #1789
Publish operator helm chart to helm.altinity.com in addition to artifacthub.io

Full Changelog: release-0.25.3...release-0.25.4

release-0.25.3

2025-08-08T07:25:10Z

Added

Added support for pdbMaxUnavailable in CHK
Added .spec.configuration.clusters[].pdbManaged for CHI and CHK that allow to set external PDBs by @zrudzionis in #1768

Fixed

Add ZK error handling and logging by @wilkermichael in #1762
Fixed collision between PDBs for CHI and CHK with the same name. As a side effect PDB for CHI will be re-created with this upgrade
Fixed rare panic in buildCRFromObj() when it can not find CR
Fixed update of storage configmap that might block in rare cases. Closes #1781
Fixed the check for host to be included in remote_servers, that did not work correctly in some network configurations. Closes #1782

Helm updates

feat(helm): add priority class to helm chart by @nobletooth in #1774
feat(helm): publish as an OCI helm package as well by @ogirardot in #1779
There is no 'helm repo upgrade', should be 'update' by @CaptTofu in #1780
Hotfix port names, to avoid warning during helm install by @Slach in #1784

New Contributors

@wilkermichael made their first contribution in #1762
@zrudzionis made their first contribution in #1768
@nobletooth made their first contribution in #1774
@ogirardot made their first contribution in #1779
@CaptTofu made their first contribution in #1780

Full Changelog: release-0.25.2...release-0.25.3

release-0.25.2

2025-07-10T15:05:16Z

Fixed

Refactored concurrent reconcile code to fix #1749
Changed ClickHouse version detection code to reduce number of calls
Force-skipped replica wait code for the first host in the cluster
Fixed clickhouse-keeper manifests for old Kubernetes versions by @Slach in #1767

Full Changelog: release-0.25.1...release-0.25.2

release-0.25.1

2025-07-01T21:14:25Z

Added

Added an option to substitute macros in settings, can be enabled in spec.reconciling CHI section.

Fixed

Fix panic by @alex-zaitsev in #1750. Closes #1749
Fixed rootCA parsing. Closes #1666
Added ownerReference in chi-storage config map. Closes #1714
Fixed a bug when CHI was not included in the monitoring on operator restart until the end of reconcile
Fixed a bug with podTemplate env variables being incorrectly merged from CHI template

Helm/misc changes

reproduce dashboard installation for grafana helm chart by @Slach in #1725
Edited template for ServiceMonitor by @virtualb0x in #1728
add example for schema bootstrap via startup_scripts, fix https://git… by @Slach in #1732
feat: users with SSL Auth by @viktordebulat in #1739
fix service monitor template by @Slach in #1747
Update grafana and prometheus, update grafana dashboards by @Slach in #1752

New Contributors

@virtualb0x made their first contribution in #1728
@viktordebulat made their first contribution in #1739

Full Changelog: release-0.25.0...release-0.25.1

release-0.25.0

2025-12-19T14:01:05Z

Added

Multiple service templates are now supported for a single purpose. Example of syntax:

  defaults:
    templates:
      serviceTemplates:
       - service-template
       - service-template-internal

Added availabilityZone attribute for ZooKeeper spec:

  configuration:
    zookeeper: # Add Zookeeper
      nodes:
        - host: zookeeper
          port: 2181
          availabilityZone: "my-azone"

Operator can now inject version specific ClickHouse configuration, it is configured in 'addons' section of operator configuration. This closes #1603 but can be used for other use cases as well
Added an option to specify reconciling.runtime.reconcileShardsThreadsNumber and reconcilingShardsMaxConcurrencyPercent on the CHI level
[Helm] ServiceMonitor additional configuration by @nlamirault in #1624
[Helm] Add namespace override capability for multi-namespace deployments by @bwdmr in #1640
[Helm] Add common labels and annotations to all resources by @dashashutosh80 in #1692
[Helm] Add support for rbac at namespace scope in @dashashutosh80 #1698

Changed

BACKWARD INCOMPATIBLE: macros USERS, COMMON, HOST in files section were deprecated. config.d, users.d, cond.d should be used instead, i.e if old syntax like this has been used:

  configuration:
    files:
      USERS/grants.xml

It should be replaced by this:

  configuration:
    files:
      users.d/grants.xml

When a new cluster is started with reconcilingShardsMaxConcurrencyPercent=100, all shards are created in parallel. Previously, first shard was always created alone.
The new option to wait for replication to catch up when adding a new replica is enabled by default. It can be configured in operator reconcile settings:

reconcile:
  host:
    wait:
      replicas:
        all: no
        new: yes
        delay: 10

Fixed

Fixed a bug with underlying replicated tables were not properly created when adding new nodes sometimes. Closes #1689
Fixed a bug when service was not updated if clusterIP is changed from missing to None in service template
Fixed a bug when annotations were not removed from service if removed from service template

New Contributors

@nlamirault made their first contribution in #1624
@bwdmr made their first contribution in #1640
@DougTidwell made their first contribution in #1660
@dashashutosh80 made their first contribution in #1692

Full Changelog: release-0.24.5...release-0.25.0