ceph-csi/docs/deploy-rbd.md

CSI RBD Plugin

The RBD CSI plugin is able to provision new RBD images and attach and mount those to workloads.

Building

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

Building binary:

make rbdplugin

Building Docker image:

make image-rbdplugin

Configuration

Available command line arguments:

Option	Default value	Description
--endpoint	unix://tmp/csi.sock	CSI endpoint, must be a UNIX socket
--drivername	csi-cephfsplugin	name of the driver (Kubernetes: provisioner field in StorageClass must correspond to this value)
--nodeid	empty	This node's ID
--containerized	true	Whether running in containerized mode
--metadatastorage	empty	Whether should metadata be kept on node as file or in a k8s configmap (node or k8s_configmap)

Available environmental variables:

HOST_ROOTFS: rbdplugin searches /proc directory under the directory set by HOST_ROOTFS.

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	one of monitors and monValueFromSecret must be set	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.
pool	yes	Ceph pool into which the RBD image shall be created
imageFormat	no	RBD image format. Defaults to 2. See man pages
imageFeatures	no	RBD image features. Available for imageFormat=2. CSI RBD currently supports only layering feature. See man pages
csi.storage.k8s.io/provisioner-secret-name, csi.storage.k8s.io/node-publish-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-publish-secret-namespace	for Kubernetes	namespaces of the above Secret objects
mounter	no	if set to rbd-nbd, use rbd-nbd on nodes that have rbd-nbd and nbd kernel modules to map rbd images
fsType	no	allows setting to `ext3
multiNodeWritable	no	if set to enabled allows RBD volumes with MultiNode Access Modes to bypass watcher checks. By default multiple attachments of an RBD volume are NOT allowed. Even if this option is set in the StorageClass, it's ignored if a standard SingleNodeWriter Access Mode is requested

Warning for multiNodeWritable:

NOTE the multiNodeWritable setting is NOT safe for use by workloads that are not designed to coordinate access. This does NOT add any sort of a clustered filesystem or write syncronization, it's specifically for special workloads that handle access coordination on their own (ie Active/Passive scenarios).

Using this mode for general purposes WILL RESULT IN DATA CORRUPTION. We attempt to limit exposure to trouble here but ignoring the Storage Class setting unless your Volume explicitly asks for multi node access, and assume you know what you're doing.

Required secrets:

Admin credentials are required for provisioning new RBD images ADMIN_NAME: ADMIN_PASSWORD - note that the key of the key-value pair is the name of the client with admin privileges, and the value is its password

Deployment with Kubernetes

Requires Kubernetes 1.11

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/rbd/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-rbdplugin-attacher.yaml
kubectl create -f csi-rbdplugin-provisioner.yaml

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

Deploy RBD CSI driver:

kubectl create -f csi-rbdplugin.yaml

Deploys a daemon set with two containers: CSI driver-registrar and the CSI RBD 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-rbdplugin-attacher-0      1/1       Running   0          23s
pod/csi-rbdplugin-fptqr           2/2       Running   0          21s
pod/csi-rbdplugin-provisioner-0   1/1       Running   0          22s

NAME                                TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)     AGE
service/csi-rbdplugin-attacher      ClusterIP   10.109.15.54   <none>        12345/TCP   26s
service/csi-rbdplugin-provisioner   ClusterIP   10.104.2.130   <none>        12345/TCP   23s

...

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

Deployment with Helm

The same requirements from the Kubernetes section apply here, i.e. Kubernetes version, privileged flag and shared mounts.

The Helm chart is located in deploy/rbd/helm.

Deploy Helm Chart:

helm install ./deploy/rbd/helm

The Helm chart deploys all of the required resources to use the CSI RBD driver. After deploying the chart you can verify the deployment using the instructions above for verifying the deployment with Kubernetes