Ceph CSI

Overview

RBD CSI plugin implements an interface between CSI enabled Container Orchestrator and CEPH cluster. It allows dynamically provision CEPH volumes and attach it to workloads. Current implementation of CSI RBD plugin was tested in Kubernetes environment, but its code does not rely on any Kubernetes specific calls (WIP to make it k8s agnostic) and should be able to run with any CSI enabled CO (Containers Orchestration).

An RBD CSI plugin is available to help simplify storage management. Once user creates PVC with the reference to a RBD storage class, rbd image and corresponding PV object gets dynamically created and becomes ready to be used by workloads.

Container Storage Interface (CSI) driver, provisioner, and attacher for Ceph RBD and CephFS

RBD Plugin

Configuration Requirements

• Secret object with the authentication key for ceph cluster
• StorageClass with rbdplugin (default CSI RBD plugin name) as a provisioner name and information about ceph cluster (monitors, pool, etc)
• Service Accounts with required RBAC permissions

Feature Status

CSI Spec version

v0.1.0 branch of ceph-csi repo correpsonds to version 0.1.0 of CSI spec, in order for a plugin to operate sucessfully, other components: external-attacher, external-provisioner and driver-registrar must be built for the same CSI spec version.

1.9: Alpha

Important: CSIPersistentVolume and MountPropagation feature gates must be enabled starting in 1.9. Also API server must run with running config set to: storage.k8s.io/v1alpha1

Compiling

CSI RBD plugin can be compiled in a form of a binary file or in a form of a container. When compiled as a binary file, it gets stored in _output folder with the name rbdplugin. When compiled as a container, the resulting image is stored in a local docker's image store.

To compile just a binary file:

$ make rbdplugin

To build a container:

$ make container

By running:

$ docker images | grep rbdplugin

You should see the following line in the output:

csi_images/rbdplugin   v0.1.0  248ddba297fa        30 seconds ago    431 MB

Testing

Prerequisite

Enable Mount Propagation in Docker

Comment out MountFlags=slave in docker systemd service then restart docker service.

# systemctl daemon-reload
# systemctl restart docker

Enable Kubernetes Feature Gates

Enable features MountPropagation=true,CSIPersistentVolume=true and runtime config storage.k8s.io/v1alpha1=true

Step 1: Create Secret

$ kubectl create -f ./deploy/kubernetes/rbd-secrets.yaml 

Important: rbd-secrets.yaml, must be customized to match your ceph environment.

Step 2: Create StorageClass

$ kubectl create -f ./deploy/kubernetes/rbd-storage-class.yaml

Important: rbd-storage-class.yaml, must be customized to match your ceph environment.

Step 3: Start CSI CEPH RBD plugin

$ kubectl create -f ./deploy/kubernetes/rbdplugin.yaml

Step 4: Start CSI External Attacher

$ kubectl create -f ./deploy/kubernetes/csi-attacher.yaml

Step 5: Start CSI External Provisioner

$ kubectl create -f ./deploy/kubernetes/csi-provisioner.yaml

Important: Deployment yaml files includes required Service Account definitions and required RBAC rules.

Step 6: Check status of CSI RBD plugin

$ kubectl get pods | grep csi 

The following output should be displayed:

NAMESPACE     NAME                                                READY     STATUS    RESTARTS   AGE          
default       csi-attacher-0                                      1/1       Running   0          1d           
default       csi-nodeplugin-rbdplugin-qxqtl                      2/2       Running   0          1d           
default       csi-provisioner-0                                   1/1       Running   0          1d           

Step 7: Create PVC

$ kubectl create -f ./deploy/kubernetes/pvc.yaml

Step 8: Check status of provisioner PV

$ kubectl get pv

The following output should be displayed:

NAME                                                          CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS    CLAIM             STORAGECLASS   REASON    AGE
kubernetes-dynamic-pvc-1b19ddf1-0047-11e8-85ab-760f2eed12ea   5Gi        RWO            Delete           Bound     default/csi-pvc   rbdv2                    10s

$ kubectl describe pv kubernetes-dynamic-pvc-1b19ddf1-0047-11e8-85ab-760f2eed12ea
Name:            kubernetes-dynamic-pvc-1b19ddf1-0047-11e8-85ab-760f2eed12ea
Annotations:     csi.volume.kubernetes.io/volume-attributes={"monitors":"192.168.80.233:6789","pool":"kubernetes"}
                 csiProvisionerIdentity=1516716490787-8081-rbdplugin  <------ !!!
                 pv.kubernetes.io/provisioned-by=rbdplugin
StorageClass:    rbdv2              <------ !!!
Status:          Bound              <------ !!!
Claim:           default/csi-pvc    <------ !!!
Reclaim Policy:  Delete
Access Modes:    RWO
VolumeMode:      Filesystem
Capacity:        5Gi
Message:         
Source:
    Type:    CSI <------ !!!

Step 9: Create a test pod

# kubectl create -f ./deploy/pod.yaml

CephFS plugin

TODO

Troubleshooting

Please submit an issue at:Issues