Automatic merge from submit-queue (batch tested with PRs 62657, 63278, 62903, 63375). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Add more volume types in e2e and fix part of them.
**What this PR does / why we need it**:
- Add dir-link/dir-bindmounted/dir-link-bindmounted/bockfs volume types for e2e tests.
- Fix fsGroup related e2e tests partially.
- Return error if we cannot resolve volume path.
- Because we should not fallback to volume path, if it's a symbolic link, we may get wrong results.
To safely set fsGroup on local volume, we need to implement these two methods correctly for all volume types both on the host and in container:
- get volume path kubelet can access
- paths on the host and in container are different
- get mount references
- for directories, we cannot use its mount source (device field) to identify mount references, because directories on same filesystem have same mount source (e.g. tmpfs), we need to check filesystem's major:minor and directory root path on it
Here is current status:
| | (A) volume-path (host) | (B) volume-path (container) | (C) mount-refs (host) | (D) mount-refs (container) |
| --- | --- | --- | --- | --- |
| (1) dir | OK | FAIL | FAIL | FAIL |
| (2) dir-link | OK | FAIL | FAIL | FAIL |
| (3) dir-bindmounted | OK | FAIL | FAIL | FAIL |
| (4) dir-link-bindmounted | OK | FAIL | FAIL | FAIL |
| (5) tmpfs| OK | FAIL | FAIL | FAIL |
| (6) blockfs| OK | FAIL | OK | FAIL |
| (7) block| NOTNEEDED | NOTNEEDED | NOTNEEDED | NOTNEEDED |
| (8) gce-localssd-scsi-fs| NOTTESTED | NOTTESTED | NOTTESTED | NOTTESTED |
- This PR uses `nsenter ... readlink` to resolve path in container as @msau42 @jsafrane [suggested](https://github.com/kubernetes/kubernetes/pull/61489#pullrequestreview-110032850). This fixes B1:B6 and D6, , the rest will be addressed in https://github.com/kubernetes/kubernetes/pull/62102.
- C5:D5 marked `FAIL` because `tmpfs` filesystems can share same mount source, we cannot rely on it to check mount references. e2e tests passes due to we use unique mount source string in tests.
- A7:D7 marked `NOTNEEDED` because we don't set fsGroup on block devices in local plugin. (TODO: Should we set fsGroup on block device?)
- A8:D8 marked `NOTTESTED` because I didn't test it, I leave it to `pull-kubernetes-e2e-gce`. I think it should be same as `blockfs`.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
In our CI, we run kubekins image for most of the jobs. This is a
debian image with upstart and does not enable systemd. So we should:
* Bailout if any binary is missing other than systemd-run.
* SupportsSystemd should check the binary path to correctly
identify if the systemd-run is present or not
* Pass the errors back to the callers so kubelet is forced to
fail early when there is a problem. We currently assume
that all binaries are in the root directory by default which
is wrong.
Users must not be allowed to step outside the volume with subPath.
Therefore the final subPath directory must be "locked" somehow
and checked if it's inside volume.
On Windows, we lock the directories. On Linux, we bind-mount the final
subPath into /var/lib/kubelet/pods/<uid>/volume-subpaths/<container name>/<subPathName>,
it can't be changed to symlink user once it's bind-mounted.
Kubelet makes sure that /var/lib/kubelet is rshared when it starts.
If not, it bind-mounts it with rshared propagation to containers
that mount volumes to /var/lib/kubelet can benefit from mount propagation.
Added IsNotMountPoint method to mount utils (pkg/util/mount/mount.go)
Added UnmountMountPoint method to volume utils (pkg/volume/util/util.go)
Call UnmountMountPoint method from local storage (pkg/volume/local/local.go)
IsLikelyNotMountPoint behavior was not modified, so the logic/behavior for UnmountPath is not modified
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.
IsLikelyNotMountPoint determines if a directory is not a mountpoint.
It is fast but not necessarily ALWAYS correct. If the path is in fact
a bind mount from one part of a mount to another it will not be detected.
mkdir /tmp/a /tmp/b; mount --bin /tmp/a /tmp/b; IsLikelyNotMountPoint("/tmp/b")
will return true. When in fact /tmp/b is a mount point. So this patch
renames the function and switches it from a positive to a negative (I
could think of a good positive name). This should make future users of
this function aware that it isn't quite perfect, but probably good
enough.
Matthew Wong