Check for init container failures and InvalidImageName

[DrJosh9000]

What

Check for init containers that fail.
Check for containers that can't pull because the image name is invalid.
If either of these things happens, acquire and fail the job.

Why

If an init container fails, "app" (post-init) containers do not run. This includes the agent, so nothing reports the failure to BK and the job remains unstarted.

Failing the job instead exposes the failure in the job log, and prevents the controller from eventually trying to re-create a potentially doomed job. Adding an init container to the podSpec as a way to check some precondition needed to run a job is also more useful.

InvalidImageName does not cause init containers to fail in the same way, but is somewhat similar to ImagePullBackOff. The container tries to start, and k8s continues trying forever, without resulting in an exit. Unlike ImagePullBackOff, we can reasonably assume InvalidImageName has no chance to resolve itself, so failing the BK job ignores the grace period in that case.