An admin wants to specify in which GCE availability zone(s) users may create persistent volumes using dynamic provisioning.
That's why the admin can now configure in StorageClass object a comma separated list of zones. Dynamically created PVs for PVCs that use the StorageClass are created in one of the configured zones.
Gluster provisioner is interested in pvc.Namespace and I don't want to add
at as a new field in VolumeOptions - it would contain almost whole PVC.
Let's pass direct reference to PVC instead and let the provisioner to pick
information it is interested in.
We had a long-lasting bug which prevented creation of volumes in
non-master zones, because the cloudprovider in the volume label
admission controller is not initialized with the multizone setting
(issue #27656).
This implements a simple workaround: if the volume is created with the
failure-domain zone label, we look for the volume in that zone. This is
more efficient, avoids introducing a new semantic, and allows users (and
the dynamic provisioner) to create volumes in non-master zones.
Fixes#27657
Long term we plan on integrating this into the scheduler, but in the
short term we use the volume name to place it onto a zone.
We hash the volume name so we don't bias to the first few zones.
If the volume name "looks like" a PetSet volume name (ending with
-<number>) then we use the number as an offset. In that case we hash
the base name.
Fixes#27256
Volume names have now format <cluster-name>-dynamic-<pv-name>.
pv-name is guaranteed to be unique in Kubernetes cluster, adding
<cluster-name> ensures we don't conflict with any running cluster
in the cloud project (kube-controller-manager --cluster-name=XXX).
'kubernetes' is the default cluster name.
GCE disks don't have tags, we must encode the tags into Description field.
It's encoded as JSON, which is both human and machine readable:
description: '{"kubernetes.io/created-for/pv/name":"pv-gce-oxwts","kubernetes.io/created-for/pvc/name":"myclaim","kubernetes.io/created-for/pvc/namespace":"default"}'
We adapt the existing code to work across all zones in a region.
We require a feature-flag to enable Ubernetes-Lite
Reasons:
* There are some behavioural changes if users create volumes with
the same name in two zones.
* We don't want to make one API call per zone if we're not running
Ubernetes-Lite.
* Ubernetes-Lite is still experimental.
There isn't a parallel flag implemented for AWS, because at the moment
there would be no behaviour changes from this.
A lot of packages use StringSet, but they don't use anything else from
the util package. Moving StringSet into another package will shrink
their dependency trees significantly.
The GCE PD plugin uses safe_format_and_mount found on standard GCE images:
https://github.com/GoogleCloudPlatform/compute-image-packages/blob/master/google-startup-scripts/usr/share/google/safe_format_and_mount
On custom images where this is not available pods fail to format and
mount GCE PDs. This patch uses linux utilities in a similar way to the
safe_format_and_mount script to format and mount the GCE PD and AWS EBC
devices. That is first attempt a mount. If mount fails try to use file to
investigate the device. If 'file' fails to get any information about
the device and simply returns "data" then assume the device is not
formatted and format it and attempt to mount it again.
Signed-off-by: Sami Wagiaalla <swagiaal@redhat.com>
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.
Chao Xu