Automatic merge from submit-queue
Add Events for operation_executor to show status of mounts, failed/successful to show in describe events
Fixes#27590
@saad-ali @pmorie @erinboyd
After talking with @pmorie last week about the above issue, I decided to poke around and see if I could remedy. The refactoring broke my previous UXP merged PR's that correctly showed failed mount errors in the describe events. However, Not sure I implemented correctly, but it tested out and seems to be working, let me know what I missed or if this is not the correct approach.
```
Events:
FirstSeen LastSeen Count From SubobjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
2m 2m 1 {default-scheduler } Normal Scheduled Successfully assigned nfs-bb-pod1 to 127.0.0.1
44s 44s 1 {kubelet 127.0.0.1} Warning FailedMount Unable to mount volumes for pod "nfs-bb-pod1_default(a94f64f1-37c9-11e6-9aa5-52540073d346)": timeout expired waiting for volumes to attach/mount for pod "nfs-bb-pod1"/"default". list of unattached/unmounted volumes=[nfsvol]
44s 44s 1 {kubelet 127.0.0.1} Warning FailedSync Error syncing pod, skipping: timeout expired waiting for volumes to attach/mount for pod "nfs-bb-pod1"/"default". list of unattached/unmounted volumes=[nfsvol]
38s 38s 1 {kubelet } Warning FailedMount Unable to mount volumes for pod "a94f64f1-37c9-11e6-9aa5-52540073d346": Mount failed: exit status 32
Mounting arguments: nfs1.rhs:/opt/data99 /var/lib/kubelet/pods/a94f64f1-37c9-11e6-9aa5-52540073d346/volumes/kubernetes.io~nfs/nfsvol nfs []
Output: mount.nfs: Connection timed out
Resolution hint: Check and make sure the NFS Server exists (ensure that correct IPAddress/Hostname was given) and is available/reachable.
Also make sure firewall ports are open on both client and NFS Server (2049 v4 and 2049, 20048 and 111 for v3).
Use commands telnet <nfs server> <port> and showmount <nfs server> to help test connectivity.
```
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.
For non-attachable volumes, do not call GetVolumeName on the plugin and instead
generate a unique name based on the identity of the pod and the name of the volume
within the pod.
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.
Ensure that kublet marks VolumeInUse before checking if it is Attached.
Also ensures that the attach/detach controller always fetches a fresh
copy of the node object before detach (instead ofKubelet relying on node
informer cache).
Modify attach/detach controller to keep track of volumes to report
attached in Node VolumeToAttach status.
Modify kubelet volume manager to wait for volume to show up in Node
VolumeToAttach status.
Implement exponential backoff for errors in volume manager and attach
detach controller
This commit adds a new volume manager in kubelet that synchronizes
volume mount/unmount (and attach/detach, if attach/detach controller
is not enabled).
This eliminates the race conditions between the pod creation loop
and the orphaned volumes loops. It also removes the unmount/detach
from the `syncPod()` path so volume clean up never blocks the
`syncPod` loop.
