While there might be no immediate practical use for this in a regular Docker workflow, sharing namespaces between containers is a widely used technique employed by:
- Kubernetes Pods, including ephemeral containers
- Container debugging tools (
cdebug,docker debug,kubectl debug, etc.) - Infrastructure projects (e.g., iximiuz Labs playground engine)
In this challenge, you'll need to start a new container in the namespaces of another, already running container, effectively making it a sidecar:
- The
targetcontainer is a simple HTTP API server that already runs in the background - You need to start a new container, called
sidecar, that runs an interactive shell inside - You can use any image for the
sidecarcontainer (busyboxoralpineare good choices) - The
sidecarcontainer should share the PID, IPC, and network namespaces of thetargetcontainer (instead of creating its own)
Good luck!
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