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README.md

Unity CSI

This repo contains [Container Storage Interface(CSI)] (https://github.com/container-storage-interface/) Unity CSI driver for DellEMC.

Overview

Unity CSI plugins implement an interface between CSI enabled Container Orchestrator(CO) and Unity Storage Array. It allows dynamically provisioning Unity volumes and attaching them to workloads.

Introduction

The CSI Driver For Dell EMC Unity conforms to CSI spec 1.1

CSI Driver For Dell EMC Unity Capabilities

Capability Supported Not supported
Provisioning Persistent volumes creation, deletion, mounting, unmounting, listing Volume expand
Export, Mount Mount volume as file system Raw volumes, Topology
Data protection Creation of snapshots Cloning, Create volume from snapshots
Types of volumes Static, Dynamic
Access mode Single Node read/write Multi Node access modes
Kubernetes v1.14 V1.13 or previous versions
OS RHEL 7.5, 7.6. CentOs 7.6 Ubuntu, other Linux variants
Unity OE 5.0 Previous versions
Protocol FC iSCSI, NFS

Installation overview

The Helm chart installs CSI Driver for Unity using a shell script (helm/install.unity). This script installs the CSI driver container image along with the required Kubernetes sidecar containers.

The controller section of the Helm chart installs the following components in a Stateful Set in the namespace unity:

  • CSI Driver for Unity
  • Kubernetes Provisioner, which provisions the provisioning volumes
  • Kubernetes Attacher, which attaches the volumes to the containers
  • Kubernetes Snapshotter, which provides snapshot support

The node section of the Helm chart installs the following component in a Daemon Set in the namespace unity:

  • CSI Driver for Unity
  • Kubernetes Registrar, which handles the driver registration

Prerequisites

Before you install CSI Driver for Unity, verify the requirements that are mentioned in this topic are installed and configured.

Requirements

  • Install Kubernetes.
  • Enable the Kubernetes feature gates
  • Configure Docker service
  • Install Helm and Tiller with a service account
  • Deploy Unity using Helm

Enable Kubernetes feature gates

The Kubernetes feature gates must be enabled before installing CSI Driver for Unity.

About Enabling Kubernetes feature gates

The Feature Gates section of Kubernetes home page lists the Kubernetes feature gates. The following Kubernetes feature gates must be enabled:

  • VolumeSnapshotDataSource
  • KubeletPluginsWatcher
  • CSINodeInfo
  • CSIDriverRegistry
  • BlockVolume
  • CSIBlockVolume

Procedure

  1. On each master and node of Kubernetes, edit /var/lib/kubelet/config.yaml and append the following lines at the end to set feature-gate settings for the kubelets: /var/lib/kubelet/config.yaml

    VolumeSnapshotDataSource: true
    KubeletPluginsWatcher: true
    CSINodeInfo: true
    CSIDriverRegistry: true
    BlockVolume: true
    CSIBlockVolume: true
    ExpandCSIVolumes: true
    
  2. On the master node, set the feature gate settings of the kube-apiserver.yaml, kube-controllermanager.yaml and kube-scheduler.yaml file as follows:

    /etc/kubernetes/manifests/kube-apiserver.yaml /etc/kubernetes/manifests/kube-controller-manager.yaml /etc/kubernetes/manifests/kube-scheduler.yaml

    - --feature-gates=VolumeSnapshotDataSource=true,KubeletPluginsWatcher=true,CSINodeInfo=true,CSIDriverRegistry=true,BlockVolume=true,CSIBlockVolume=true,ExpandCSIVolumes=true
    
  3. On each node (including master), edit the variable KUBELET_KUBECONFIG_ARGS of /usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf file as follows:

    Environment="KUBELET_KUBECONFIG_ARGS=--bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf --feature-gates=VolumeSnapshotDataSource=true,KubeletPluginsWatcher=true,CSINodeInfo=true,CSIDriverRegistry=true,BlockVolume=true,CSIBlockVolume=true,ExpandCSIVolumes=true" 
    
  4. Restart the kublet on all nodes.

    systemctl daemon-reload
    systemctl restart kubelet 
    

Configure Docker service

The mount propagation in Docker must be configured on all Kubernetes nodes before installing CSI Driver for Unity.

Procedure

  1. Edit the service section of /etc/systemd/system/multi-user.target.wants/docker.service file as follows:

    [Service]
    ...
    MountFlags=shared
    
  2. Restart the Docker service with systemctl daemon-reload and

    systemctl daemon-reload
    systemctl restart docker
    

Install CSI Driver for Unity

Install CSI Driver for Unity using this procedure.

Before you begin

  • You must have the downloaded files, including the Helm chart from the source git repository, ready for this procedure.
  • In the top-level helm directory, there should be two shell scripts, install.unity and uninstall.unity. These scripts handle some of the pre and post operations that cannot be performed in the helm chart, such as creating Custom Resource Definitions (CRDs), if needed.

Procedure

  1. Collect information from the Unity System like IP address, username and password. Make a note of the value for these parameters as they must be entered in the myvalues.yaml file.

  2. Copy the csi-unity/values.yaml into a file in the same directory as the install.unity named myvalues.yaml, to customize settings for installation.

  3. Edit myvalues.yaml to set the following parameters for your installation:

    The following table lists the primary configurable parameters of the Unity driver chart and their default values. More detailed information can be found in the values.yaml file in this repository.

    Parameter Description Required Default
    systemName Name of the Unity system false unity
    restGateway REST API gateway HTTPS endpoint Unity system true -
    storagePool Unity Storage Pool CLI ID to use with in the Kubernetes storage class true -
    unityUsername Username for accessing unity system true -
    unityPassword Password for accessing unity system true -
    volumeNamePrefix String to prepend to any volumes created by the driver false csivol
    storageClass.name Name of the storage class to be defined false unity
    storageClass.isDefault Whether or not to make this storage class the default false true
    storageClass.reclaimPolicy What should happen when a volume is removed false Delete
    Storage Class parameters Following parameters are not present in values.yaml
    FsType To set File system type. Possible values are ext3,ext4,xfs false ext4
    volumeThinProvisioned To set volume thinProvisioned false true
    isVolumeDataReductionEnabled To set volume data reduction false false
    volumeTieringPolicy To set volume tiering policy false 0
    hostIOLimitName To set unity host IO limit false ""
    Snapshot Class parameters Following parameters are not present in values.yaml
    snapshotRetentionDuration TO set snapshot retention duration. Format:"1:23:52:50" (number of days:hours:minutes:sec) false ""

    Use the following command to convert username/password to base64 encoded string

    echo -n 'admin' | base64
    echo -n 'password' | base64 
    

    Example myvalues.yaml

    storagePool: pool_1
    restGateway: "https://<Ip of Unity system>"  
    unityUsername: <Base64 encoded string>  
    unityPassword: <Base64 encoded string>
    images:
       driver: <docker image>
    
  4. Run the sh install.unity command to proceed with the installation.

    A successful installation should emit messages that look similar to the following samples:

    sh install.unity 
    Kubernetes version v1.14.2
    Kubernetes master nodes: 10.*.*.*
    Kubernetes minion nodes:
    Verifying the feature gates.
    NAME:   unity
    LAST DEPLOYED: Wed Aug 14 01:23:35 2019
    NAMESPACE: unity
    STATUS: DEPLOYED
    [....]
    NAME                 READY   STATUS    RESTARTS   AGE
    unity-controller-0   4/4     Running   0          21s
    unity-node-kzv49     2/2     Running   0          21s
    CSIDrivers:
    No resources found.
    CSINodeInfos:
    No resources found.
    StorageClasses:
    NAME              PROVISIONER   AGE
    unity (default)   csi-unity     21s
    

    Results At the end of the script, the kubectl get pods -n unity is called to GET the status of the pods and you will see the following:

    • unity-controller-0 with 4/4 containers ready, and status displayed as Running.
    • Agent pods with 2/2 containers and the status displayed as Running.

    Finally, the script lists the created storageclasses such as, "unity". Additional storage classes can be created for different combinations of file system types and Unity storage pools. The script also creates volumesnapshotclass "unity-snapclass".

Test deploying a simple pod with Unity storage

Test the deployment workflow of a simple pod on Unity storage.

  1. Verify Unity system for Host

    After helm deployment CSI Driver for Node will create new Host(s) in the Unity system depending on the number of node in kubernetes cluster. Verify Unity system for new Hosts and Initattors

  2. Creating a volume:

    Create a file (pvc.yaml) with the following content

    apiVersion: v1
    kind: PersistentVolumeClaim
    metadata:
      name: testvolclaim1
    spec:
      accessModes:
      - ReadWriteOnce
      resources:
        requests:
          storage: 5Gi
      storageClassName: unity
    

    Execute the following command to create volume

    kubectl create -f $PWD/pvc.yaml
    

    Result: After executing the above command PVC will be created in the default namespace, and the user can see the pvc by executing kubectl get pvc. Note: Verify unity system for the new volume

  3. Attach the volume to Host

    To attach a volume to a host, create a new application(Pod) and use the PVC created above in the Pod. This scenario is explained using the Nginx application. Create nginx.yaml with the following content.

    apiVersion: v1
    kind: Pod
    metadata:
      name: ngnix-pv-pod
    spec:
      containers:
        - name: task-pv-container
          image: nginx
          ports:
            - containerPort: 80
              name: "http-server"
          volumeMounts:
            - mountPath: "/usr/share/nginx/html"
              name: task-pv-storage
      volumes:
        - name: task-pv-storage
          persistentVolumeClaim:
            claimName: testvolclaim1
    

    Execute the following command to mount the volume to kubernetes node

    kubectl create -f $PWD/nginx.yaml
    

    Result: After executing the above command, new nginx pod will be successfully created and started in the default namespace. Note: Verify unity system for volume to be attached to the Host where the nginx container is running

  4. Create Snapshot

    The following procedure will create a snapshot of the volume in the container using VolumeSnapshot objects defined in snap.yaml. The following are the contents of snap.yaml.

    snap.yaml

    apiVersion: snapshot.storage.k8s.io/v1alpha1
    kind: VolumeSnapshot
    metadata:
        name: testvolclaim1-snap1        
    spec:
        snapshotClassName: unity-snapclass
        source:
            name: testvolclaim1
            kind: PersistentVolumeClaim
    

    Execute the following command to create snapshot

    kubectl create -f $PWD/snap.yaml
    

    The spec.source section contains the volume that will be snapped in the default namespace. For example, if the volume to be snapped is testvolclaim1, then the created snapshot is named testvolclaim1-snap1. Verify the unity system for new snapshot under the lun section.

    Note:

    • User can see the snapshots using kubectl get volumesnapshot
    • Notice that this VolumeSnapshot class has a reference to a snapshotClassName:unity-snapclass. The CSI Driver for Unity installation creates this class as its default snapshot class.
    • You can see its definition using kubectl get volumesnapshotclasses unity-snapclass -o yaml.
  5. Delete Snapshot

    Execute the following command to delete the snapshot

    kubectl get volumesnapshot
    kubectl delete volumesnapshot testvolclaim1-snap1
    
  6. To Unattach the volume from Host

    Delete the nginx application to unattach the volume from host

    kubectl delete -f nginx.yaml

  7. To delete the volume

    kubectl get pvc
    kubectl delete pvc testvolclaim1
    kubectl get pvc
    

Support

The CSI Driver for Dell EMC Unity image available on Dockerhub is officially supported by Dell EMC.

The source code available on Github is unsupported and provided solely under the terms of the license attached to the source code. For clarity, Dell EMC does not provide support for any source code modifications.

For any CSI driver setup, configuration issues, questions or feedback, join the Dell EMC Container community athttps://www.dell.com/community/Containers/bd-p/Containers

For any Dell EMC storage issues, please contact Dell support at: https://www.dell.com/support.

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