Migrate CI/CD workflows to Helm 4

[dirien]

Summary

Helm 4.0 was released in November 2025, marking the first major version update in six years. This issue tracks the work needed to migrate our GitHub workflows from Helm 3.19.4 to Helm 4.

Current State

• lint-and-test.yml: Uses Helm v3.19.4
• publish.yaml: Uses Helm v3.19.4

Timeline

Helm 3 support ends:

• Bug fixes: July 8, 2026
• Security fixes: November 11, 2026

Breaking Changes to Address

1. Server-Side Apply (SSA)

Helm 4 uses Server-Side Apply by default instead of three-way merge. This changes how conflicts are handled during upgrades.

Action: Test chart installations and upgrades with SSA enabled. Use --force-conflicts=true flag if needed during transition.

2. Plugin System Redesign

Post-renderers must now be plugins (WebAssembly-based plugin support added).

Action: Review if any post-renderer workflows exist and update them to use the new plugin format.

3. Registry Login Changes

helm registry login now requires domain name only (not full registry path).

Action: Review and update any registry authentication commands in workflows.

4. CLI Flag Renaming

Various CLI flags have been renamed in Helm 4.

Action: Audit all helm commands in workflows and scripts for deprecated flags.

5. Chart Format

Helm 4 introduces chart v3 format while maintaining v2 compatibility.

Action: Evaluate if migrating to chart v3 format provides benefits.

Migration Steps

• Research: Review full Helm 4 changelog for all breaking changes
• Local Testing: Install Helm 4 locally and test chart linting, templating, and installation
• CI Testing: Create a test branch with Helm 4 in workflows and verify all jobs pass
• Test Chart Install: Verify chart installs correctly with Helm 4 on a test cluster
• Test Chart Upgrade: Test upgrading existing Helm 3 releases to Helm 4
• Update lint-and-test.yml: Bump Helm version to v4.x
• Update publish.yaml: Bump Helm version to v4.x
• Update Documentation: Note Helm 4 compatibility in chart README if needed
• Verify OCI Push: Ensure helm push to GHCR works with Helm 4

Resources

• Helm 4 Released Announcement
• Helm 4 Overview
• Helm 4 Full Changelog
• Helm 4 Migration Guide

Priority

Medium - Helm 3 remains supported until November 2026, but early migration allows us to benefit from Helm 4 features and avoid last-minute rushes.