ceph-csi/docs/deploy-cephfs.md

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 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 cephcsi. When compiled as an image, it's stored in the local Docker image store with name cephcsi.

Building binary:

make cephcsi

Building Docker image:

make image-cephcsi

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
--type	empty	Driver type `[rbd
--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.
--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.
--instanceid	"default"	Unique ID distinguishing this instance of Ceph CSI among other instances, when sharing Ceph clusters across CSI instances for provisioning
--metadatastorage	empty	Points to where older (1.0.0 or older plugin versions) metadata about provisioned volumes are kept, as file or in as k8s configmap (node or k8s_configmap respectively)

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
clusterID	yes	String representing a Ceph cluster, must be unique across all Ceph clusters in use for provisioning, cannot be greater than 36 bytes in length, and should remain immutable for the lifetime of the Ceph cluster in use
fsName	yes	CephFS filesystem name into which the volume shall be created
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.
pool	yes	Ceph pool into which the volume shall be created
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

NOTE: An accompanying CSI configuration file, needs to be provided to the running pods. Refer to Creating CSI configuration for more information.

NOTE: A suggested way to populate and retain uniqueness of the clusterID is to use the output of ceph fsid of the Ceph cluster to be used for provisioning.

Required secrets for provisioning: Admin credentials are required for provisioning new volumes

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

Required secrets for statically provisioned volumes: 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-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-provisioner.yaml

Deploys stateful set of provision which includes external-provisioner ,external-attacher for CSI CephFS.

Deploy CSI CephFS driver:

kubectl create -f csi-cephfsplugin.yaml

Deploys a daemon set with two containers: CSI node-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-provisioner-0   3/3       Running   0          25s
pod/csi-cephfsplugin-rljcv           2/2       Running   0          24s

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

Once the CSI plugin configuration is updated with details from a Ceph cluster of choice, you can try deploying a demo pod from examples/cephfs using the instructions provided to test the deployment further.

Notes on volume deletion

Dynamically povisioned volumes are deleted by the driver, when requested to do so. Statically provisioned volumes, from plugin versions less than or equal to 1.0.0, are a no-op when a delete operation is performed against the same, and are expected to be deleted on the Ceph cluster by the user.