General:

• Kubernetes APIs used by operator have been updated to 1.15. Operator does not use features from new APIs, so it keeps working with Kubernetes 1.12 and above. Operator is tested for compatibility with different k8s versions, and we did not face any issues.

New features:

• Ability to re-scale storage, both by enlarging volume size for existing installations in volumeClaimTemplate, and by adding extra volumes. That requires pod restarts.
• Operator re-creates a StatefulSet if there are changes that can not be applied to an existing object
• Configurable namespaceNamePattern and statefulSetNamePattern (#360 by @qixiaogang), see example
  • https://github.com/Altinity/clickhouse-operator/blob/master/docs/chi-examples/18-namespace-domain-pattern.yaml
  • https://github.com/Altinity/clickhouse-operator/blob/master/docs/chi-examples/19-pod-generate-name.yaml
• New exported metrics 'metric.ChangedSettingsHash', 'metric.LongestRunningQuery' and 'active 'label for table sizes.
• Numerous improvements to Grafana dashboard

Bug fixes:

• Set 'internal_replication' to false for single replica clusters (#422 by @yuzhichang)
• Fixed schema creation logic when adding new replica (#385), improved stability in general for different types of objects
• Service selectors did not include namespace, that could lead to a conflict in multi-namespace environment. It is fixed now.
• Operator generated ClickHouse configuration files using standard names, like 'settings.xml'. It might lead to a conflict with user configuration files. Now all generated config files are prefixed with 'chop-generated-'.

Upgrade notes: When operator is upgraded from the previous version, it re-creates statefulsets and pods to ensure they match the installation. The storage should be correctly re-attached. As a side effect it ensures there are no backwards incompatibility issues between operator versions.