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deploy-cephfs.md

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CSI CephFS plugin

The CSI CephFS plugin is able to both provision new CephFS volumes and attach and mount existing ones to workloads.

Building

CSI CephFS plugin can be compiled in the form of a binary file or in the form of a Docker image. When compiled as a binary file, the result is stored in _output/ directory with the name cephfsplugin. When compiled as an image, it's stored in the local Docker image store.

Building binary:

make cephfsplugin

Building Docker image:

make image-cephfsplugin

Configuration

Available command line arguments:

Option Default value Description
--endpoint unix://tmp/csi.sock CSI endpoint, must be a UNIX socket
--drivername cephfs.csi.ceph.com name of the driver (Kubernetes: provisioner field in StorageClass must correspond to this value)
--nodeid empty This node's ID
--volumemounter empty default volume mounter. Available options are kernel and fuse. This is the mount method used if volume parameters don't specify otherwise. If left unspecified, the driver will first probe for ceph-fuse in system's path and will choose Ceph kernel client if probing failed.
--metadatastorage empty Whether metadata should be kept on node as file or in a k8s configmap (node or k8s_configmap)
--mountcachedir empty volume mount cache info save dir. If left unspecified, the dirver will not record mount info, or it will save mount info and when driver restart it will remount volume it cached.

Available environmental variables:

KUBERNETES_CONFIG_PATH: if you use k8s_configmap as metadata store, specify the path of your k8s config file (if not specified, the plugin will assume you're running it inside a k8s cluster and find the config itself).

POD_NAMESPACE: if you use k8s_configmap as metadata store, POD_NAMESPACE is used to define in which namespace you want the configmaps to be stored

Available volume parameters:

Parameter Required Description
monitors yes Comma separated list of Ceph monitors (e.g. 192.168.100.1:6789,192.168.100.2:6789,192.168.100.3:6789)
monValueFromSecret one of monitors and monValueFromSecret must be set a string pointing the key in the credential secret, whose value is the mon. This is used for the case when the monitors' IP or hostnames are changed, the secret can be updated to pick up the new monitors. If both monitors and monValueFromSecret are set and the monitors set in the secret exists, monValueFromSecret takes precedence.
mounter no Mount method to be used for this volume. Available options are kernel for Ceph kernel client and fuse for Ceph FUSE driver. Defaults to "default mounter", see command line arguments.
provisionVolume yes Mode of operation. BOOL value. If true, a new CephFS volume will be provisioned. If false, an existing volume will be used.
pool for provisionVolume=true Ceph pool into which the volume shall be created
rootPath for provisionVolume=false Root path of an existing CephFS volume
csi.storage.k8s.io/provisioner-secret-name, csi.storage.k8s.io/node-stage-secret-name for Kubernetes name of the Kubernetes Secret object containing Ceph client credentials. Both parameters should have the same value
csi.storage.k8s.io/provisioner-secret-namespace, csi.storage.k8s.io/node-stage-secret-namespace for Kubernetes namespaces of the above Secret objects

Required secrets for provisionVolume=true: Admin credentials are required for provisioning new volumes

  • adminID: ID of an admin client
  • adminKey: key of the admin client

Required secrets for provisionVolume=false: User credentials with access to an existing volume

  • userID: ID of a user client
  • userKey: key of a user client

Notes on volume size: when provisioning a new volume, max_bytes quota attribute for this volume will be set to the requested volume size (see Ceph quota documentation). A request for a zero-sized volume means no quota attribute will be set.

Deployment with Kubernetes

Requires Kubernetes 1.13

Your Kubernetes cluster must allow privileged pods (i.e. --allow-privileged flag must be set to true for both the API server and the kubelet). Moreover, as stated in the mount propagation docs, the Docker daemon of the cluster nodes must allow shared mounts.

YAML manifests are located in deploy/cephfs/kubernetes.

Deploy RBACs for sidecar containers and node plugins:

kubectl create -f csi-attacher-rbac.yaml
kubectl create -f csi-provisioner-rbac.yaml
kubectl create -f csi-nodeplugin-rbac.yaml

Those manifests deploy service accounts, cluster roles and cluster role bindings. These are shared for both RBD and CephFS CSI plugins, as they require the same permissions.

Deploy CSI sidecar containers:

kubectl create -f csi-cephfsplugin-attacher.yaml
kubectl create -f csi-cephfsplugin-provisioner.yaml

Deploys stateful sets for external-attacher and external-provisioner sidecar containers for CSI CephFS.

Deploy CSI CephFS driver:

kubectl create -f csi-cephfsplugin.yaml

Deploys a daemon set with two containers: CSI driver-registrar and the CSI CephFS driver.

Verifying the deployment in Kubernetes

After successfully completing the steps above, you should see output similar to this:

$ kubectl get all
NAME                                 READY     STATUS    RESTARTS   AGE
pod/csi-cephfsplugin-attacher-0      1/1       Running   0          26s
pod/csi-cephfsplugin-provisioner-0   1/1       Running   0          25s
pod/csi-cephfsplugin-rljcv           2/2       Running   0          24s

NAME                                   TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)     AGE
service/csi-cephfsplugin-attacher      ClusterIP   10.104.116.218   <none>        12345/TCP   27s
service/csi-cephfsplugin-provisioner   ClusterIP   10.101.78.75     <none>        12345/TCP   26s

...

You can try deploying a demo pod from examples/cephfs to test the deployment further.

Notes on volume deletion

Volumes that were provisioned dynamically (i.e. provisionVolume=true) are allowed to be deleted by the driver as well, if the user chooses to do so.Otherwise, the driver is forbidden to delete such volumes - attempting to delete them is a no-op.