Important Concept: Immutability and Persistence

A frequent source of confusion is how Docker-based Frappe deployments handle persistence.

Containers Are Immutable

Docker containers are not meant to be modified after they are built. You should only change:

• Environment variables
• Mounted volumes
• The Docker image itself (via rebuild)

What Is Persistent

Typically, only these paths are persisted:

• Site data (/sites)
• Database storage

This allows you to:

• Create new sites
• Run migrations
• Perform backups and restores
• Recreate containers safely

Installing Apps After Deployment

❌ Not Supported

Installing apps into a running container is not supported.

bench get-app and bench build are examples of an common but unsupported actions.

Why?

• Apps and assets are part of the Docker image
• Runtime changes are lost on container recreation
• This ensures reproducibility and stability

Correct Workflow

1. Add the app to the image build configuration
2. Rebuild the Docker image
3. Redeploy the stack

This applies to all production-oriented setups.