The plugins get called by scheduler goroutines. At least the polling seems to
be done concurrently and thus needs locking.
Locking the PreBindPlugin state is less obvious. It might be that the scheduler
is really done with the test pod, but that ordering doesn't seem to be enough
for the race detector. It's simpler to add mutex locking.
PVCs using the ReadWriteOncePod access mode can only be referenced by a
single pod. When a pod is scheduled that uses a ReadWriteOncePod PVC,
return "Unschedulable" if the PVC is already in-use in the cluster.
To support preemption, the "VolumeRestrictions" scheduler plugin
computes cycle state during the PreFilter phase. This cycle state
contains the number of references to the ReadWriteOncePod PVCs used by
the pod-to-be-scheduled.
During scheduler simulation (AddPod and RemovePod), we add and remove
reference counts from the cycle state if they use any of these
ReadWriteOncePod PVCs.
In the Filter phase, the scheduler checks if there are any PVC reference
conflicts, and returns "Unschedulable" if there is a conflict.
This is a required feature for the ReadWriteOncePod beta. See for more context:
https://github.com/kubernetes/enhancements/tree/master/keps/sig-storage/2485-read-write-once-pod-pv-access-mode#beta
Before, in RunPostFilterPlugins, we didn't distinguish between unschedulable and unresolvable
because we only have one postFilterPlugin by default, now, we have at least two, we should
make sure that once a postFilterPlugin returns unresolvable, we'll return directly
Signed-off-by: Kante Yin <kerthcet@gmail.com>
Tests scheduler enforcement of the ReadWriteOncePod PVC access mode.
- Creates a pod using a PVC with ReadWriteOncePod
- Creates a second pod using the same PVC
- Observes the second pod fails to schedule because PVC is in-use
- Deletes the first pod
- Observes the second pod successfully schedules
- PreemptionByKubeScheduler (Pod preempted by kube-scheduler)
- DeletionByTaintManager (Pod deleted by taint manager due to NoExecute taint)
- EvictionByEvictionAPI (Pod evicted by Eviction API)
- DeletionByPodGC (an orphaned Pod deleted by PodGC)PreemptedByScheduler (Pod preempted by kube-scheduler)
- Run hack/update-codegen.sh
- Run hack/update-generated-device-plugin.sh
- Run hack/update-generated-protobuf.sh
- Run hack/update-generated-runtime.sh
- Run hack/update-generated-swagger-docs.sh
- Run hack/update-openapi-spec.sh
- Run hack/update-gofmt.sh
Signed-off-by: Davanum Srinivas <davanum@gmail.com>
