chore(opensearch): bump OS 3.x test environments to 3.8.0 (#37059)

[fabrizzio-dotCMS]

Proposed Changes

Fixes #37059

Every OpenSearch 3.x target in the repo was pinned to 3.4.0 or older, while the latest released OpenSearch 3.x is 3.8.0. This bumps all of them.

File	Setting	Before	After
docker/docker-compose-examples/single-node-os-migration/docker-compose.yml	opensearch3 image	3.4.0	3.8.0
docker/docker-compose-examples/single-node-os-migration/docker-compose.yml	opensearch3-dashboards image	3.0.0	3.8.0
environments/environment.properties	docker.image.search.upgrade	3.4.0	3.8.0
dotCMS/src/docker-compose/it-test/docker-compose.yml	OS_IMAGE_UPGRADE default	3.0.0	3.8.0

Plus the docs that spelled the version out: the single-node-os-migration README service table and docs/backend/OPENSEARCH_MIGRATION_TESTER_GUIDE.md (which described the target engine as "OpenSearch 3.4").

A drift worth calling out: the it-test compose fallback was 3.0.0 — older than what Maven actually injects from environment.properties (3.4.0). Anyone running that compose file directly got a different engine than CI did. Both now say 3.8.0.

What is deliberately not touched — every 1.x pin stays exactly where it is. That includes docker.image.search=opensearchproject/opensearch:1.3.6 (the <opensearch> container in parent/pom.xml, i.e. the engine every integration test runs against), the ES_IMAGE fallbacks in the it-test / local-run composes, the CLI test resources, and the ~10 examples on opensearchproject/opensearch:1 (single-node, cluster-mode, with-redis, experiments, lgtm-observability, push-publish, dev-env/Dockerfile).

Per docs/backend/OPENSEARCH_MIGRATION.md, the ES / OS 1.x side is the engine we are migrating away from — its lifecycle runs active → active (fallback) → decommissioned across phases 0–3. It is a frozen baseline, not a version target. Only the OS 3.x side (the shadow index that gets promoted to primary at Phase 3) moves forward. Bumping the 1.x baseline would also put every integration test on a different engine than the one the migration is defined against, for no migration benefit.

Why

From the OpenSearch migration status thread in #feat-opensearch-upgrade (Aug 13, 2026) — Todd Jacobsen:

Our docker-compose examples use opensearch 3.4 but the latest available version is 3.8. We should bump all our OS test envs to 3.8 and check for compatibility

Added urgency: single-node-os-migration is the reference stack we're about to hand to a self-hosted customer so they can test the LTS→EG changeover together with the OpenSearch upgrade. It shouldn't ship pointing four minors behind.

Checklist

• Tests — see below; the version bump is what drives them
• Documentation updated
• Followed Contributing Guidelines

How to Test

docker.image.search.upgrade feeds the opensearch-upgrade Maven profile (dotcms-integration/pom.xml) and every phase-suite run, so CI on this PR is the compatibility check — no separate harness needed.

1. Upgrade suite against OS 3.8.0:

   just test-integration-upgrade
   # or: ./mvnw verify -pl :dotcms-integration -Dcoreit.test.skip=false -Dopensearch.upgrade.test=true

2. Phase sweep — exercises dual-write, OS reads, and the Phase 3 cutover:

   just test-integration-phase-all

3. The example stack boots clean:

   cd docker/docker-compose-examples/single-node-os-migration && docker compose up -d

   Both provisioners should complete, dotCMS should start, and content should index into the OS 3.8.0 cluster (https://localhost:9201, dashboards on http://localhost:5602).

Latest tags verified on Docker Hub 2026-08-13: opensearchproject/opensearch → 3.8.0, opensearchproject/opensearch-dashboards → 3.8.0.

🤖 Generated with Claude Code

[claude]

Claude finished @fabrizzio-dotCMS's task in 40s —— View job

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PR Review: bump OS 3.x test environments to 3.8.0

• Read PR diff against origin/main
• Verify compose image pins and check for lingering 3.4.0/3.0.0 references
• Post review

No issues found.

This is a config/docs-only version bump. I verified:

• docker-compose.yml — dashboards image and the two header comments now read 3.8.0. The opensearch3 engine image at line 97 is already opensearchproject/opensearch:3.8.0, so the PR-body table row claiming 3.4.0 → 3.8.0 for that image doesn't correspond to a change in this diff (final state is correct either way — just a cosmetic mismatch in the description, not a code problem).
• environment.properties — docker.image.search.upgrade → 3.8.0; the docker.image.search=…:1.3.6 1.x baseline correctly left untouched per the migration lifecycle.
• it-test/docker-compose.yml — OS_IMAGE_UPGRADE default → 3.8.0, resolving the 3.0.0 drift the PR body flags.
• Docs (README.md, OPENSEARCH_MIGRATION_TESTER_GUIDE.md) — updated to 3.8/3.8.0 consistently.
• Grepped docker/, dotCMS/src/docker-compose/, environments/, and the tester guide — no remaining OpenSearch 3.4.0/3.0.0 pins. The only 3.4.0/3.4.5 hits are unrelated Maven plugin versions in parent/pom.xml.

Correctness of the actual 3.8.0 engine compatibility is what CI on this PR validates (upgrade + phase suites), as noted in the description — that's the right gate for this change.

• branch issue-37059-bump-opensearch-3-8-0

[claude]

(test comment retracted)