Don't restart pods on some config changes#115
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Pull request overview
This PR aims to prevent unnecessary ClickHouse pod restarts for configuration changes that ClickHouse can reload dynamically (e.g., ExtraUsersConfig), while still restarting pods for config changes that require it.
Changes:
- Add a “restart-required config hash” annotation to StatefulSets and use it to decide whether a ConfigMap change should trigger a pod restart.
- If restart is not required, issue ClickHouse
SYSTEM RELOAD CONFIG/SYSTEM RELOAD USERScommands instead of restarting pods. - Add an e2e test asserting that
ExtraUsersConfigupdates do not restart pods.
Reviewed changes
Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.
Show a summary per file
| File | Description |
|---|---|
test/e2e/clickhouse_e2e_test.go |
Adds an e2e scenario validating no pod restart on ExtraUsersConfig changes. |
internal/controllerutil/annotations.go |
Introduces an annotation key + helpers for storing/retrieving the restart-required config hash. |
internal/controller/clickhouse/templates.go |
Defines which generated config keys are considered restart-required and computes a hash for them. |
internal/controller/clickhouse/sync.go |
Updates reconcile logic to restart only when restart-required config changes; otherwise reload in-place. |
internal/controller/clickhouse/commands.go |
Adds commander methods to run ClickHouse SYSTEM RELOAD CONFIG/USERS. |
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GrigoryPervakov
approved these changes
May 22, 2026
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Why
Some configuration updates don't require a pod restart. This pull request improves that behavior.
What
Annotate generated config files with RequiresRestart and split the config revision into reloadable and restartable parts.
Track config runtime reload with a reserved named collection key.
Related Issues
Related to #15