This makes two main changes:
- Runs syncPod in a separate Go routine (and enforces only one of those
runs at a time).
- Uses the pod list to determine if a container should be running or
should be killed (used to use the output of syncPod).
Since Docker pulls are synchronized by the Docker daemon we still block
on that, but pods can now be removed and prepared for starting without
blocking on long pulls.
Also transfer the Kubelet from using ContainerManifest.ID to source specific
identifiers with namespacing. Move goroutine behavior out of kubelet/ and
into integration.go and cmd/kubelet/kubelet.go for better isolation.
When no tag is given to Docker pull, it downloads all tags. This could be a
significantly large number of images and in the end we only ever run
:latest.