https://www.elastic.co/guide/en/elasticsearch/reference/6.8/breaking-changes-6.8.html" rel="nofollow">https://www.elastic.co/guide/en/elasticsearch/reference/6.8/breaking-changes-6.8.html) There are [four "release highlights"](https://www.elastic.co/guide/en/elasticsearch/reference/6.8/release-highlights.html) in this upgrade: - two licensing changes (in 6.8.0) - an OOM error fix for cross-cluster replication (which we don't use) - a fix for retries in cross-cluster replication (which we don't use) There are no changes that I've seen regarding to relevance in the [full release notes](https://www.elastic.co/guide/en/elasticsearch/reference/6.8/es-release-notes.html). There are several [security fixes including one for log4j](https://www.elastic.co/guide/en/elasticsearch/reference/6.8/release-notes-6.8.21.html). Internal Process ---------------- There are some docs on what happens during minor version upgrades: - https://aws.amazon.com/blogs/database/in-place-version-upgrades-for-amazon-elasticsearch-service/ - https://aws.amazon.com/opensearch-service/faqs/#topic-8 - https://aws.amazon.com/blogs/big-data/an-automated-approach-to-perform-an-in-place-engine-upgrade-in-amazon-opensearch-service/ Older docs say that minor versions are an inplace upgrade. Each node is removed from the cluster, upgraded and then re-added. Newer docs (which might be less relevant given the venerable age of our version) indicate that it might be a blue/green deployment. In either case, downtime for queries is not expected. Our Process ----------- 1. Run the [preflight checks](https://docs.publishing.service.gov.uk/manual/reindex-elasticsearch.html#1-preflight-checks) to ensure that we don't have duplicate indices hanging around. 2. [Take a manual snapshot](https://docs.aws.amazon.com/opensearch-service/latest/developerguide/managedomains-snapshot-create.html) of the index. 3. Deploy this TF change. On production especially, this should be done at a quiet time. 4. Consider [replaying content changes](https://docs.publishing.service.gov.uk/manual/fix-out-of-date-search-indices.html) that may have happened during the upgrade. Rollback -------- Rollback involves creating a new Elasticsearch cluster and restoring the snapshot. Environment Sync ---------------- I don't expect this to affect the environment sync that occurs overnight.

Commits

Commits on Oct 2, 2025

Upgrade integration elasticsearch