Ephemeral Containers

A feature new to the 1.16 version is the ability to add a container to a running pod. This would allow a feature-filled container to be added to an existing pod without having to terminate and re-create. Intermittent and difficult to determine problems may take a while to reproduce, or not exist with the addition of another container.

As an alpha stability feature, it may change or be removed at any time. As well, they will not be restarted automatically, and several resources such as ports or resources are not allowed.

These containers are added via the ephemeralcontainers handler via an API call, not via the podSpec. As a result, the use of kubectl edit is not possible.

You may be able to use the kubectl attach command to join an existing process within the container. This can be helpful instead of kubectl exec, which executes a new process. The functionality of the attached process depends entirely on what you are attaching to.

kubectl debug buggypod --image debian --attach