This change removes RuntimeCache in the pod workers and the syncPod() function.
Note that it doesn't deprecate RuntimeCache completely as other components
still rely on the cache.
This address a TODO when collecting the node version information so it
will properly report the configured runtime and its version. Previously,
this was hardcoded to "docker://" and the docker version, and would show
"docker://1.9.1" even when the kubelet was configured to use rkt.
With this change, it will use the runtime's Type() and Version() data.
This also changes the container.Runtime interface to add an APIVersion()
method. This can be used when the runtime has separate versions for the
engine and the API, such as with Docker. The Docker minimum version
validation has been updated to use APIVersion(), and
DockerManager.Version() now returns the engine version.
This cache will be used to stores the PodStatus of all pods/containers
visible on the node. This will elimiate the need for pod workers to query the
container runtime directly.
Currently, pleg would report a event if a container transitions from running to
exited between relisting. However, if would not report any event if a container
gets stopped and removed between relisting. This event will eventually be
handled when the pod syncs periodically, but this is undesirable. This change
ensures that we detect all such events.
Refactor Kubelet's server functionality into a server package. Most
notably, move pkg/kubelet/server.go into
pkg/kubelet/server/server.go. This will lead to better separation of
concerns and a more readable code hierarchy.
This feature is no longer useful pods don't sync as often. For batch
creation/deletions/syncs, the cache will be up-to-date for most pods since it
will be updated frequently. For other cases, continue updating for two more
seconds don't usually help, as temporal locality doesn't hold across pod syncs.
This change introduces pod lifecycle event generator (PLEG), and adds a generic
PLEG. The generic PLEG relies on relisting to discover container events, and is
container-runtime-agnostic. Both docker and rkt are changed to use generic
PLEG.
Change all references to the container ID in pkg/kubelet/... to the
strong type defined in pkg/kubelet/container: ContainerID
The motivation for this change is to make the format of the ID
unambiguous, specifically whether or not it includes the runtime
prefix (e.g. "docker://").
Each container with a readiness has an individual go-routine which
handles periodic probing for that container. The results are cached, and
written to the status.Manager in the pod sync path.
