C4 Level 2: Container Diagram

In the C4 model, a container is an application or data store that must be running for the software system to work. It is not necessarily a Docker container, Kubernetes workload, virtual machine, process, repository, or team.

Keep the logical container view separate from a C4 deployment diagram:

• Container diagram: applications/data stores, responsibilities, technologies, and communication.
• Deployment diagram: instances of software systems/containers deployed onto infrastructure nodes in a particular environment.

A single C4 container may have multiple runtime instances, sidecars, jobs, or infrastructure resources. Conversely, a deployment unit can package more than one logical concern. Record the mapping in a deployment view only when it is useful.

Workflow