Usecase: A node in the Kubernetes cluster is replaced with a new node. The
new node gets a different `kubernetes.io/hostname`. The storage devices
that were attached to the old node are re-attached to the new node.
Fix: Instead of using the default `kubenetes.io/hostname` as the node affinity
label, this commit changes to use `openebs.io/nodeid`. The ZFS LocalPV driver
will pick the value from the nodes and set the affinity.
Once the old node is removed from the cluster, the K8s scheduler will continue
to schedule applications on the old node only.
User can now modify the value of `openebs.io/nodeid` on the new node to the same
value that was available on the old node. This will make sure the pods/volumes are
scheduled to the node now.
Note: Now to migrate the PV to the other node, we have to move the disks to the other node
and remove the old node from the cluster and set the same label on the new node using
the same key, which will let k8s scheduler to schedule the pods to that node.
Other updates:
* adding faq doc
* renaming the config variable to nodename
Signed-off-by: Pawan <pawan@mayadata.io>
Co-authored-by: Akhil Mohan <akhilerm@gmail.com>
* Update docs/faq.md
Co-authored-by: Akhil Mohan <akhilerm@gmail.com>
as it does the management task also corrected few logs
and renamed zvol to zfs(as we support zvol and dataset both)
Signed-off-by: Pawan <pawan@mayadata.io>
This is an initial scheduler implementation for ZFS Local PV.
* adding scheduler as a configurable option
* adding volumeWeightedScheduler as scheduling logic
The volumeWeightedScheduler will go through all the nodes as per
topology information and it will pick the node which has less
volume provisioned in the given pool.
lets say there are 2 nodes node1 and node2 with below pool configuration :-
```
node1
|
|-----> pool1
| |
| |------> pvc1
| |------> pvc2
|-----> pool2
|------> pvc3
node2
|
|-----> pool1
| |
| |------> pvc4
|-----> pool2
|------> pvc5
|------> pvc6
```
So if application is using pool1 as shown in the below storage class, then ZFS driver will schedule it on node2 as it has one volume as compared to node1 which has 2 volumes in pool1.
```yaml
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: openebs-zfspv
provisioner: zfs.csi.openebs.io
parameters:
blocksize: "4k"
compression: "on"
dedup: "on"
thinprovision: "yes"
poolname: "pool1"
```
So if application is using pool2 as shown in the below storage class, then ZFS driver will schedule it on node1 as it has one volume only as compared node2 which has 2 volumes in pool2.
```yaml
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: openebs-zfspv
provisioner: zfs.csi.openebs.io
parameters:
blocksize: "4k"
compression: "on"
dedup: "on"
thinprovision: "yes"
poolname: "pool2"
```
In case of same number of volumes on all the nodes for the given pool, it can pick any node and schedule the PV on that.
Signed-off-by: Pawan <pawan@mayadata.io>
provisioning and deprovisioning of
the volumes on the node where zfs pool
has already been setup. Pool name and the volume
parameters has to be given in storage class
which will be used to provision the volume.
Signed-off-by: Pawan <pawan@mayadata.io>
