97f8c4b677
This commit provides the option to pass in Ceph cluster-id instead of a MON list from the storage class. This helps in moving towards a stateless CSI implementation. Tested the following, - PV provisioning and staging using cluster-id in storage class - PV provisioning and staging using MON list in storage class Did not test, - snapshot operations in either forms of the storage class Signed-off-by: ShyamsundarR <srangana@redhat.com> |
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cephfs | ||
rbd | ||
README.md |
How to test RBD and CephFS plugins with Kubernetes 1.13
Both rbd
and cephfs
directories contain plugin-deploy.sh
and
plugin-teardown.sh
helper scripts. You can use those to help you
deploy/teardown RBACs, sidecar containers and the plugin in one go.
By default, they look for the YAML manifests in
../../deploy/{rbd,cephfs}/kubernetes
.
You can override this path by running $ ./plugin-deploy.sh /path/to/my/manifests
.
Once the plugin is successfully deployed, you'll need to customize
storageclass.yaml
and secret.yaml
manifests to reflect your Ceph cluster
setup.
Please consult the documentation for info about available parameters.
NOTE: See section
Cluster ID based configuration if using
the clusterID
instead of monitors
or monValueFromSecret
options in the
storage class for RBD based provisioning before proceeding.
After configuring the secrets, monitors, etc. you can deploy a testing Pod mounting a RBD image / CephFS volume:
kubectl create -f secret.yaml
kubectl create -f storageclass.yaml
kubectl create -f pvc.yaml
kubectl create -f pod.yaml
Other helper scripts:
logs.sh
output of the pluginexec-bash.sh
logs into the plugin's container and runs bash
How to test RBD Snapshot feature
Before continuing, make sure you enabled the required
feature gate VolumeSnapshotDataSource=true
in your Kubernetes cluster.
In the examples/rbd
directory you will find two files related to snapshots:
snapshotclass.yaml and
snapshot.yaml.
Once you created your RBD volume, you'll need to customize at least
snapshotclass.yaml
and make sure the monitors
and pool
parameters match
your Ceph cluster setup.
If you followed the documentation to create the rbdplugin, you shouldn't
have to edit any other file.
After configuring everything you needed, deploy the snapshot class:
kubectl create -f snapshotclass.yaml
Verify that the snapshot class was created:
$ kubectl get volumesnapshotclass
NAME AGE
csi-rbdplugin-snapclass 4s
Create a snapshot from the existing PVC:
kubectl create -f snapshot.yaml
To verify if your volume snapshot has successfully been created, run the following:
$ kubectl get volumesnapshot
NAME AGE
rbd-pvc-snapshot 6s
To check the status of the snapshot, run the following:
$ kubectl describe volumesnapshot rbd-pvc-snapshot
Name: rbd-pvc-snapshot
Namespace: default
Labels: <none>
Annotations: <none>
API Version: snapshot.storage.k8s.io/v1alpha1
Kind: VolumeSnapshot
Metadata:
Creation Timestamp: 2019-02-06T08:52:34Z
Finalizers:
snapshot.storage.kubernetes.io/volumesnapshot-protection
Generation: 5
Resource Version: 84239
Self Link: /apis/snapshot.storage.k8s.io/v1alpha1/namespaces/default/volumesnapshots/rbd-pvc-snapshot
UID: 8b9b5740-29ec-11e9-8e0f-b8ca3aad030b
Spec:
Snapshot Class Name: csi-rbdplugin-snapclass
Snapshot Content Name: snapcontent-8b9b5740-29ec-11e9-8e0f-b8ca3aad030b
Source:
API Group: <nil>
Kind: PersistentVolumeClaim
Name: rbd-pvc
Status:
Creation Time: 2019-02-06T08:52:34Z
Ready To Use: true
Restore Size: 1Gi
Events: <none>
To be sure everything is OK you can run rbd snap ls [your-pvc-name]
inside
one of your Ceph pod.
To restore the snapshot to a new PVC, deploy pvc-restore.yaml and a testing pod pod-restore.yaml:
kubectl create -f pvc-restore.yaml
kubectl create -f pod-restore.yaml
How to test RBD MULTI_NODE_MULTI_WRITER BLOCK feature
Requires feature-gates: BlockVolume=true
CSIBlockVolume=true
NOTE The MULTI_NODE_MULTI_WRITER capability is only available for
Volumes that are of access_type block
WARNING This feature is strictly for workloads that know how to deal with concurrent access to the Volume (eg Active/Passive applications). Using RWX modes on non clustered file systems with applications trying to simultaneously access the Volume will likely result in data corruption!
Following are examples for issuing a request for a Block
ReadWriteMany
Claim, and using the resultant Claim for a POD
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: block-pvc
spec:
accessModes:
- ReadWriteMany
volumeMode: Block
resources:
requests:
storage: 1Gi
storageClassName: csi-rbd
Create a POD that uses this PVC:
apiVersion: v1
kind: Pod
metadata:
name: my-pod
spec:
containers:
- name: my-container
image: debian
command: ["/bin/bash", "-c"]
args: [ "tail -f /dev/null" ]
volumeDevices:
- devicePath: /dev/rbdblock
name: my-volume
imagePullPolicy: IfNotPresent
volumes:
- name: my-volume
persistentVolumeClaim:
claimName: block-pvc
Now, we can create a second POD (ensure the POD is scheduled on a different node; multiwriter single node works without this feature) that also uses this PVC at the same time, again wait for the pod to enter running state, and verify the block device is available.
apiVersion: v1
kind: Pod
metadata:
name: another-pod
spec:
containers:
- name: my-container
image: debian
command: ["/bin/bash", "-c"]
args: [ "tail -f /dev/null" ]
volumeDevices:
- devicePath: /dev/rbdblock
name: my-volume
imagePullPolicy: IfNotPresent
volumes:
- name: my-volume
persistentVolumeClaim:
claimName: block-pvc
Wait for the PODs to enter Running state, check that our block device
is available in the container at /dev/rdbblock
in both containers:
$ kubectl exec -it my-pod -- fdisk -l /dev/rbdblock
Disk /dev/rbdblock: 1 GiB, 1073741824 bytes, 2097152 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 4194304 bytes / 4194304 bytes
$ kubectl exec -it another-pod -- fdisk -l /dev/rbdblock
Disk /dev/rbdblock: 1 GiB, 1073741824 bytes, 2097152 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 4194304 bytes / 4194304 bytes
Cluster ID based configuration
Before creating a storage class that uses the option clusterID
to refer to a
Ceph cluster,
NOTE: Substitute the output of ceph fsid
instead of <cluster-fsid>
in
the mentioned template YAML files, and also the Ceph admin ID and
credentials in their respective options. Further, update options like
monitors
and pools
in the respective YAML files to contain the
appropriate information.
Create the following config maps and secrets
kubectl create -f ./rbd/template-ceph-cluster-ID-provisioner-secret.yaml
kubectl create -f ./rbd/template-ceph-cluster-ID-publish-secret.yaml
kubectl create -f ./rbd/template-ceph-cluster-ID-config.yaml
Modify the deployed CSI pods to additionally pass in the config maps and secrets as volumes,
kubectl patch daemonset csi-rbdplugin --patch "$(cat ./rbd/template-csi-rbdplugin-patch.yaml)"
kubectl patch statefulset csi-rbdplugin-provisioner --patch "$(cat ./rbd/template-csi-rbdplugin-provisioner-patch.yaml)"
Restart the provisioner and node plugin daemonset.
Storage class and snapshot class, using the <cluster-fsid>
as the value for
the option clusterID
, can now be created on the cluster.
Remaining steps to test functionality remains the same as mentioned in the sections above.