This implements the proposal in:
docs/proposals/secret-configmap-downwarapi-file-mode.md
Fixes: #28317.
The mounttest image is updated so it returns the permissions of the linked file
and not the symlink itself.
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.
This fixes race conditions in configmap, secret, downwardapi & git_repo
volume plugins.
wrappedVolumeSpec vars used by volume mounters and unmounters contained
a pointer to api.Volume structs which were being patched by
NewWrapperMounter/NewWrapperUnmounter, causing race condition during
volume mounts.
Fake clientset no longer needs to be prepopulated with records: keeping
them in leads to the name conflict on creates. Also, since fake
clientset now respects namespaces, we need to correctly populate them.
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.
The key to path mapping allows pod to specify different name (thus location) of each secret.
At the same time refactor the volume plugin to use AtomicWritter to project secrets to files in a volume.
Update e2e Secrets test, the secret file permission has changed from 0444 to 0644
Remove TestPluginIdempotent as the AtomicWritter is responsible for secret creation
* Metrics will not be expose until they are hooked up to a handler
* Metrics are not cached and expose a dos vector, this must be fixed before release or the stats should not be exposed through an api endpoint
- Add volume.MetricsProvider function to Volume interface.
- Add volume.MetricsDu for providing metrics via executing "du".
- Add volulme.MetricsNil for unsupported Volumes.
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.
Rodrigo Campos