Effectively, this is an ability to take an image already pulled
to the system, and automatically mount it into one or more
containers defined in Kubernetes YAML accepted by `podman play`.
Requirements:
- The image must already exist in storage.
- The image must have at least 1 volume directive.
- The path given by the volume directive will be mounted from the
image into the container. For example, an image with a volume
at `/test/test_dir` will have `/test/test_dir` in the image
mounted to `/test/test_dir` in the container.
- Multiple images can be specified. If multiple images have a
volume at a specific path, the last image specified trumps.
- The images are always mounted read-only.
- Images to mount are defined in the annotation
"io.podman.annotations.kube.image.automount/$ctrname" as a
semicolon-separated list. They are mounted into a single
container in the pod, not the whole pod.
As we're using a nonstandard annotation, this is Podman only, any
Kubernetes install will just ignore this.
Underneath, this compiles down to an image volume
(`podman run --mount type=image,...`) with subpaths to specify
what bits we want to mount into the container.
Signed-off-by: Matt Heon <mheon@redhat.com>
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