Replace Bitnami PostgreSQL with CloudNative-PG (CNPG)

[jlav]

Description

Resolves #250

Replace the Bitnami PostgreSQL Helm subchart with CloudNative-PG (CNPG) for managing PostgreSQL instances.

Bitnami has changed their licensing model. Their charts and images now require a paid subscription, and only the latest tag is available for development purposes. We are currently using legacy versions of their images (bitnamilegacy/postgresql). CNPG is an open-source, Kubernetes-native PostgreSQL operator that is actively maintained and CNCF-certified.

This is a breaking change. Existing embedded PostgreSQL data will not be migrated. Consumers using embedded PostgreSQL will need a fresh install.

Additionally, I've removed the embedded postgres option from all the charts except for openhands. Internally, we only ever use the parent chart's postgres instance and pass connection details down into the subcharts. It's a nice simplification of the subcharts to remove embedded postgres, but it does mean that the subcharts can no longer be deployed in a standalone way. Because we only ever exercise the parent chart's embedded postgres, I'm not confident that the subcharts are well tested on their embedded postgres, and I'd like to remove the burden of having to validate and maintain that path.

The new standard database configuration options for all the charts looks like this:

  # PostgreSQL database configuration
  database:
    # Hostname of the PostgreSQL server
    host: "..."
    # Port of the PostgreSQL server
    port: "5432"
    # Database user
    user: "..."
    # Database name
    name: "..."
    # Name of the Kubernetes secret containing the database password
    secretName: "..."
    # Key within the secret that holds the password
    secretKey: "..."
    # Create the database if it does not exist
    createDatabases: false
    # Run database migrations on startup
    migrate: true

Helm Chart Checklist

• I have updated the version field in Chart.yaml for each modified chart
• I have tested the chart upgrade path from the previous version
• I have verified backwards compatibility with existing values.yaml configurations — N/A: this is an intentional breaking change
• I have updated the chart's README.md if there are any breaking changes or new required values

Test Results

Fresh install on Replicated embedded cluster (instance-1) — PASS

Admin Console Dashboard

App Home

Test Conversation

Additional Notes

• Customers using external PostgreSQL are unaffected — the external_postgres config path still works as before, just with the CNPG cluster disabled
• Database creation is handled by init containers (not CNPG bootstrap), consistent with the existing pattern

[aivong-openhands]

I see SaaS uses external DBs and there's already a migration guide here. LGTM