Container storage interface is an industry standard that enables storage vendors to develop a plugin once and have it work across a number of container orchestration systems.

MooseFS is a petabyte Open-Source distributed file system. It aims to be fault-tolerant, highly available, highly performing, scalable general-purpose network distributed file system for data centers.

MooseFS source code can be found on GitHub.

Note that a pool of MooseFS Clients that are available for use by containers is created on each node. By default the number of MooseFS Clients in the pool is 1.

• MooseFS Cluster up and running

• --allow-privileged=true flag set for both API server and kubelet (default value for kubelet is true)

1. Complete deploy/kubernetes/csi-moosefs-config.yaml configuration file with your settings:

   • master_host – domain name (recommended) or IP address of your MooseFS Master Server(s). It is an equivalent to -H master_host or -o mfsmaster=master_host passed to MooseFS Client.
   • master_port – port number of your MooseFS Master Server. It is an equivalent to -P master_port or -o mfsport=master_port passed to MooseFS Client.
   • k8s_root_dir – each mount's root directory on MooseFS. Each path is relative to this one. Equivalent to -S k8s_root_dir or -o mfssubfolder=k8s_root_dir passed to MooseFS Client.
   • driver_working_dir – a driver working directory inside MooseFS where persistent volumes, logs and metadata is stored (actual path is: k8s_root_dir/driver_working_dir)
   • mount_count – number of pre created MooseFS clients running on each node and apply:
   • mfs_logging – driver can create logs from each component in k8s_root_dir/driver_working_dir/logs directory. Boolean "true"/"false" value.

   $ kubectl apply -f deploy/kubernetes/csi-moosefs-config.yaml
   

2. ConfigMap should now be created:

   $ kubectl get configmap -n kube-system
   NAME                                 DATA   AGE
   csi-moosefs-config                   6      42s
   

3. Update deploy/kubernetes/csi-moosefs.yaml file with the image that uses required MooseFS or MooseFS Pro version and MooseFS CSI Plugin version. Default images are the latest version of the plugin and the latest version of MooseFS (Community):

   • Find plugin named csi-moosefs-plugin

   • Update the image version suffix in the plugin's section accordingly, for example:

     • 0.9.4-3.0.117 – for plugin version 0.9.4 and MooseFS Community 3.0.117
     • 0.9.4-4.44.4-pro – for plugin version 0.9.4 and MooseFS Pro 4.44.4

     You can find a complete list of available images at:
     https://registry.moosefs.com/v2/moosefs-csi-plugin/tags/list.

     Note there are two occurrences of csi-moosefs-plugin in csi-moosefs.yaml file and it is necessary to update the image version in both places of the file.

4. Deploy CSI MooseFS plugin along with CSI Sidecar Containers:

   $ kubectl apply -f deploy/kubernetes/csi-moosefs.yaml
   

5. Ensure that all the containers are ready, up and running

   kube@k-master:~$ kubectl get pods -n kube-system | grep csi-moosefs
   csi-moosefs-controller-0                   4/4     Running   0          44m
   csi-moosefs-node-7h4pj                     2/2     Running   0          44m
   csi-moosefs-node-8n5hj                     2/2     Running   0          44m
   csi-moosefs-node-n4prg                     2/2     Running   0          44m
   

   You should see a single csi-moosefs-controller-x running and csi-moosefs-node-xxxxx one per each node.

   You may also take a look at your MooseFS CGI Monitoring Interface ("Mounts" tab) to check if new Clients are connected – mount points: /mnt/controller and /mnt/${nodeId}[_${mountId}].

1. Create a persistent volume claim for 5 GiB:

   $ kubectl apply -f examples/kubernetes/dynamic-provisioning/pvc.yaml
   

2. Verify if the persistent volume claim exists and wait until it's STATUS is Bound:

   $ kubectl get pvc
   NAME             STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS      AGE
   my-moosefs-pvc   Bound    pvc-a62451d4-0d75-4f81-bfb3-8402c59bfc25   5Gi        RWX            moosefs-storage   69m
   

3. After its in Bound state, create a sample workload that mounts the volume:

   $ kubectl apply -f examples/kubernetes/dynamic-provisioning/pod.yaml
   

4. Verify the storage is mounted:

   $ kubectl exec my-moosefs-pod -- df -h /data
   Filesystem                Size      Used Available Use% Mounted on
   172.17.2.80:9421          4.2T      1.4T      2.8T  33% /data
   

   You may take a look at MooseFS CGI Monitoring Interface ("Quotas" tab) to check if a quota for 5 GiB on a newly created volume directory has been set. Dynamically provisioned volumes are stored on MooseFS in k8s_root_dir/driver_working_dir/volumes directory.

5. Clean up:

   $ kubectl delete -f examples/kubernetes/dynamic-provisioning/pod.yaml
   $ kubectl delete -f examples/kubernetes/dynamic-provisioning/pvc.yaml
   

Volume expansion can be done by updating and applying corresponding PVC specification.

Note: the volume size can only be increased. Any attempts to decrease it will result in an error. It is not recommended to resize Persistent Volume MooseFS-allocated quotas via MooseFS native tools, as such changes will not be visible in your Container Orchestrator.

Volumes can be also provisioned statically by creating or using a existing directory in k8s_root_dir/driver_working_dir/volumes. Example PersistentVolume examples/kubernetes/static-provisioning/pv.yaml definition, requires existing volume in volumes directory.

It is possible to mount any MooseFS directory inside containers using static provisioning.

1. Create a Persistent Volume (examples/kubernetes/mount-volume/pv.yaml):

   kind: PersistentVolume
   apiVersion: v1
   metadata:
     name: my-moosefs-pv-mount
   spec:
     storageClassName: ""               # empty Storage Class
     capacity:
       storage: 1Gi                     # required, however does not have any effect
     accessModes:
       - ReadWriteMany
     csi:
       driver: csi.moosefs.com
       volumeHandle: my-mount-volume   # unique volume name
       volumeAttributes:
         mfsSubDir: "/"                 # subdirectory to be mounted as a rootdir (inside k8s_root_dir)
   

2. Create corresponding Persistent Volume Claim (examples/kubernetes/mount-volume/pvc.yaml):

   kind: PersistentVolumeClaim
   apiVersion: v1
   metadata:
     name: my-moosefs-pvc-mount
   spec:
     storageClassName: ""               # empty Storage Class
     volumeName: my-moosefs-pv-mount
     accessModes:
       - ReadWriteMany
     resources:
       requests:
         storage: 1Gi                   # at least as much as in PV, does not have any effect
   

3. Apply both configurations:

   $ kubectl apply -f examples/kubernetes/mount-volume/pv.yaml
   $ kubectl apply -f examples/kubernetes/mount-volume/pvc.yaml
   

4. Verify that PVC exists and wait until it is bound to the previously created PV:

   $ kubectl get pvc
   NAME                    STATUS   VOLUME                 CAPACITY   ACCESS MODES   STORAGECLASS   AGE
   my-moosefs-pvc-mount    Bound     my-moosefs-pv-mount   1Gi        RWX                           23m
   

5. Create a sample workload that mounts the volume:

   $ kubectl apply -f examples/kubernetes/mount-volume/pod.yaml
   

6. Verify that the storage is mounted:

   $ kubectl exec -it my-moosefs-pod-mount -- ls /data
   

You should see the content of k8s_root_dir/mfsSubDir.

7. Clean up:

   $ kubectl delete -f examples/kubernetes/mount-volume/pod.yaml
   $ kubectl delete -f examples/kubernetes/mount-volume/pvc.yaml
   $ kubectl delete -f examples/kubernetes/mount-volume/pv.yaml
   

By using containers[*].volumeMounts[*].subPath field of PodSpec it is possible to specify a proper MooseFS subdirectory using only one PV/PVC pair, without creating a new one for each subdirectory:

kind: Deployment
apiVersion: apps/v1
metadata:
  name: my-site-app
spec:
  template:
    spec:
      containers:
        - name: my-frontend
          # ...
          volumeMounts:
            - name: my-moosefs-mount
              mountPath: "/var/www/my-site/assets/images"
              subPath: "resources/my-site/images"
            - name: my-moosefs-mount
              mountPath: "/var/www/my-site/assets/css"
              subPath: "resources/my-site/css"
      volumes:
        - name: my-moosefs-mount
          persistentVolumeClaim:
            claimName: my-moosefs-pvc-mount

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