Most of these could have been refactored automatically but it wouldn't
have been uglier. The unsophisticated tooling left lots of unnecessary
struct -> pointer -> struct transitions.
The status manager syncBatch() method processes the current state
of the cache, which should include all entries in the channel. Flush
the channel before we call a batch to avoid unnecessary work and
to unblock pod workers when the node is congested.
Discovered while investigating long shutdown intervals on the node
where the status channel stayed full for tens of seconds.
Add a for loop around the select statement to avoid unnecessary
invocations of the wait.Forever closure each time.
When constructing the API status of a pod, if the pod is marked for
deletion no containers should be started. Previously, if a container
inside of a terminating pod failed to start due to a container
runtime error (that populates reasonCache) the reasonCache would
remain populated (it is only updated by syncPod for non-terminating
pods) and the delete action on the pod would be delayed until the
reasonCache entry expired due to other pods.
This dramatically reduces the amount of time the Kubelet waits to
delete pods that are terminating and encountered a container runtime
error.
After a pod reaches a terminal state and all containers are complete
we can delete the pod from the API server. The dispatchWork method
needs to wait for all container status to be available before invoking
delete. Even after the worker stops, status updates will continue to
be delivered and the sync handler will continue to sync the pods, so
dispatchWork gets multiple opportunities to see status.
The previous code assumed that a pod in Failed or Succeeded had no
running containers, but eviction or deletion of running pods could
still have running containers whose status needed to be reported.
This modifies earlier test to guarantee that the "fallback" exit
code 137 is never reported to match the expectation that all pods
exit with valid status for all containers (unless some exceptional
failure like eviction were to occur while the test is running).
The kubelet must not allow a container that was reported failed in a
restartPolicy=Never pod to be reported to the apiserver as success.
If a client deletes a restartPolicy=Never pod, the dispatchWork and
status manager race to update the container status. When dispatchWork
(specifically podIsTerminated) returns true, it means all containers
are stopped, which means status in the container is accurate. However,
the TerminatePod method then clears this status. This results in a
pod that has been reported with status.phase=Failed getting reset to
status.phase.Succeeded, which is a violation of the guarantees around
terminal phase.
Ensure the Kubelet never reports that a container succeeded when it
hasn't run or been executed by guarding the terminate pod loop from
ever reporting 0 in the absence of container status.
GetAllocateResourcesPodAdmitHandler(). It is named as such to reflect its
new function. Also remove the Topology Manager feature gate check at higher level
kubelet.go, as it is now done in GetAllocateResourcesPodAdmitHandler().
- allocatePodResources logic altered to allow for container by container
device allocation.
- New type PodReusableDevices
- New field in devicemanager devicesToReuse
- Where previously we called manager.AddContainer(), we now call both
manager.Allocate() and manager.AddContainer().
- Some test cases now have two expected errors. One each
from Allocate() and AddContainer(). Existing outcomes are unchanged.
GetTopologyPodAdmitHandler() now returns a lifecycle.PodAdmitHandler
type instead of the TopologyManager directly. The handler it returns
is generally responsible for attempting to allocate any resources that
require a pod admission check. When the TopologyManager feature gate
is on, this comes directly from the TopologyManager. When it is off,
we simply attempt the allocations ourselves and fail the admission
on an unexpected error. The higher level kubelet.go feature gate
check will be removed in an upcoming PR.
In an e2e run, out of 1857 pod status updates executed by the
Kubelet 453 (25%) were no-ops - they only contained the UID of
the pod and no status changes. If the patch is a no-op we can
avoid invoking the server and continue.
