Subsequent SELinux work (see http://kep.k8s.io/1710) will need
ActualStateOfWorld populated around the time kubelet starts mounting
volumes.
Therefore reconstruct volumes before starting reconciler, but do not depend
on the desired state of world populated nor node.status - both need a
working API server, which may not be available at that time.
All reconstructed volumes are marked as Uncertain and reconciler will sort
them out - call SetUp to ensure the volume is really mounted when a pod
needs the volume or call TearDown then there is no such pod.
Finish the reconstruction when the API server becomes available:
- Clean up volumes that failed reconstruction and are not needed.
- Update devicePath of reconstructed volumes from node.status. Make sure
not to overwrite devicePath that may have been updated when the volume
was mounted by reconcile().
Hiding all this rework behind SELinuxMountReadWriteOncePod FeatureGate,
just to make sure we have a way back if this commit is buggy.
When a volume is already mounted with an unexpected SELinux label,
kubelet must unmount it first and then mount it back with the expected one.
Report an error to user, just in case the unmount takes too long.
In therory, this error should not happen too often, because two Pods with
different SELinux label will not enter Desired State of World, see
dsw.AddPodToVolume. It can happen when DSW and ASW SELinux labels only when
a volume has been deleted from DSW (= Pod was deleted) or a volume was
reconstructed after kubelet restart. In both cases, volume manager should
unmount the volume quickly.
In PodExistsInVolume with volumeObj.seLinuxMountContext != nil we know that
the volume has been previously mounted with a given SELinuxMountContext.
Either it has been mounted by this kubelet and we know it's correct or it
was by a previous instance of kubelet and the context has been
reconstructed from the filesystem. In both cases, the actual context is
correct, regardless if the volume plugin or PV access mode supports SELinux
mounts.
.. that are not migrated to CSI in 1.26 *and* are based on a block device.
NFS and CephFS may use the same volume as several PVs and then mounting
with -o context won't work.
The Desired State of World can require a different SELinux mount context than
is in the Actual State of World and it's perfectly OK. For example when
user changes SELinux context of Pods or when the context is reconstructed
after kubelet restart.
Don't spam log and don't report errors to the user as event - reconciler
will do the right thing and unmount the old volume (with wrong context) and
mount a new one in the next reconciliation. It's not an error, it's
expected workflow.
In order to improve the observability of the cpumanager,
add and populate metrics to track if the combination of
the kubelet configuration and podspec would trigger
exclusive core allocation and pinning.
We should avoid leaking any node/machine specific information
(e.g. core ids, even though this is admittedly an extreme example);
tracking these metrics seems to be a good first step, because
it allows us to get feedback without exposing details.
Signed-off-by: Francesco Romani <fromani@redhat.com>
Currently, there are some unit tests that are failing on Windows due to
various reasons:
- config options not supported on Windows.
- files not closed, which means that they cannot be removed / renamed.
- paths not properly joined (filepath.Join should be used).
- time.Now() is not as precise on Windows, which means that 2
consecutive calls may return the same timestamp.
- different error messages on Windows.
- files have \r\n line endings on Windows.
- /tmp directory being used, which might not exist on Windows. Instead,
the OS-specific Temp directory should be used.
- the default value for Kubelet's EvictionHard field was containing
OS-specific fields. This is now moved, the field is now set during
Kubelet's initialization, after the config file is read.
