Currently kubelet volume management works on the concept of desired
and actual world of states. The volume manager periodically compares the
two worlds and perform volume mount/unmount and/or attach/detach
operations. When kubelet restarts, the cache of those two worlds are
gone. Although desired world can be recovered through apiserver, actual
world can not be recovered which may cause some volumes cannot be cleaned
up if their information is deleted by apiserver. This change adds the
reconstruction of the actual world by reading the pod directories from
disk. The reconstructed volume information is added to both desired
world and actual world if it cannot be found in either world. The rest
logic would be as same as before, desired world populator may clean up
the volume entry if it is no longer in apiserver, and then volume
manager should invoke unmount to clean it up.
Automatic merge from submit-queue
pkg/various: plug leaky time.New{Timer,Ticker}s
According to the documentation for Go package time, `time.Ticker` and
`time.Timer` are uncollectable by garbage collector finalizers. They
leak until otherwise stopped. This commit ensures that all remaining
instances are stopped upon departure from their relative scopes.
Similar efforts were incrementally done in #29439 and #29114.
```release-note
* pkg/various: plugged various time.Ticker and time.Timer leaks.
```
Package goroutinemap can be structurally simplified to be more
idiomatic, concise, and free of error potential. No structural changes
are made.
It is unconventional declare `sync.Mutex` directly as a pointerized
field in a parent structure. The `sync.Mutex` operates on pointer
receivers of itself; and by relying on that, the types that contain
those fields can be safely constructed using
https://golang.org/ref/spec#The_zero_value.
The duration constants are already of type `time.Duration`, so
re-declaring that is redundant.
According to the documentation for Go package time, `time.Ticker` and
`time.Timer` are uncollectable by garbage collector finalizers. They
leak until otherwise stopped. This commit ensures that all remaining
instances are stopped upon departure from their relative scopes.
Allow mount volume operations to run in parallel for non-attachable
volume plugins.
Allow unmount volume operations to run in parallel for all volume
plugins.
Jing Xu