Ceph

PLEASE NOTE: This document applies to v0.9 version and not to the latest stable release v1.9

Ceph Storage Quickstart

This guide will walk you through the basic setup of a Ceph cluster and enable you to consume block, object, and file storage from other pods running in your cluster.

Minimum Version

Kubernetes v1.8 or higher is supported by Rook.

Prerequisites

To make sure you have a Kubernetes cluster that is ready for Rook, you can follow these instructions.

If you are using dataDirHostPath to persist rook data on kubernetes hosts, make sure your host has at least 5GB of space available on the specified path.

TL;DR

If you’re feeling lucky, a simple Rook cluster can be created with the following kubectl commands. For the more detailed install, skip to the next section to deploy the Rook operator.

cd cluster/examples/kubernetes/ceph
kubectl create -f operator.yaml
kubectl create -f cluster.yaml

After the cluster is running, you can create block, object, or file storage to be consumed by other applications in your cluster.

Deploy the Rook Operator

The first step is to deploy the Rook system components, which include the Rook agent running on each node in your cluster as well as Rook operator pod.

cd cluster/examples/kubernetes/ceph
kubectl create -f operator.yaml

# verify the rook-ceph-operator, rook-ceph-agent, and rook-discover pods are in the `Running` state before proceeding
kubectl -n rook-ceph-system get pod

You can also deploy the operator with the Rook Helm Chart.

Create a Rook Cluster

Now that the Rook operator, agent, and discover pods are running, we can create the Rook cluster. For the cluster to survive reboots, make sure you set the dataDirHostPath property that is valid for your hosts. For more settings, see the documentation on configuring the cluster.

Save the cluster spec as cluster.yaml:

#################################################################################
# This example first defines some necessary namespace and RBAC security objects.
# The actual Ceph Cluster CRD example can be found at the bottom of this example.
#################################################################################
apiVersion: v1
kind: Namespace
metadata:
  name: rook-ceph
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: rook-ceph-osd
  namespace: rook-ceph
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: rook-ceph-mgr
  namespace: rook-ceph
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: rook-ceph-osd
  namespace: rook-ceph
rules:
- apiGroups: [""]
  resources: ["configmaps"]
  verbs: [ "get", "list", "watch", "create", "update", "delete" ]
---
# Aspects of ceph-mgr that require access to the system namespace
kind: Role
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: rook-ceph-mgr-system
  namespace: rook-ceph
rules:
- apiGroups:
  - ""
  resources:
  - configmaps
  verbs:
  - get
  - list
  - watch
---
# Aspects of ceph-mgr that operate within the cluster's namespace
kind: Role
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: rook-ceph-mgr
  namespace: rook-ceph
rules:
- apiGroups:
  - ""
  resources:
  - pods
  - services
  verbs:
  - get
  - list
  - watch
- apiGroups:
  - batch
  resources:
  - jobs
  verbs:
  - get
  - list
  - watch
  - create
  - update
  - delete
- apiGroups:
  - ceph.rook.io
  resources:
  - "*"
  verbs:
  - "*"
---
# Allow the operator to create resources in this cluster's namespace
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: rook-ceph-cluster-mgmt
  namespace: rook-ceph
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: rook-ceph-cluster-mgmt
subjects:
- kind: ServiceAccount
  name: rook-ceph-system
  namespace: rook-ceph-system
---
# Allow the osd pods in this namespace to work with configmaps
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: rook-ceph-osd
  namespace: rook-ceph
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: rook-ceph-osd
subjects:
- kind: ServiceAccount
  name: rook-ceph-osd
  namespace: rook-ceph
---
# Allow the ceph mgr to access the cluster-specific resources necessary for the mgr modules
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: rook-ceph-mgr
  namespace: rook-ceph
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: rook-ceph-mgr
subjects:
- kind: ServiceAccount
  name: rook-ceph-mgr
  namespace: rook-ceph
---
# Allow the ceph mgr to access the rook system resources necessary for the mgr modules
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: rook-ceph-mgr-system
  namespace: rook-ceph-system
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: rook-ceph-mgr-system
subjects:
- kind: ServiceAccount
  name: rook-ceph-mgr
  namespace: rook-ceph
---
# Allow the ceph mgr to access cluster-wide resources necessary for the mgr modules
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: rook-ceph-mgr-cluster
  namespace: rook-ceph
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: rook-ceph-mgr-cluster
subjects:
- kind: ServiceAccount
  name: rook-ceph-mgr
  namespace: rook-ceph
---
#################################################################################
# The Ceph Cluster CRD example
#################################################################################
apiVersion: ceph.rook.io/v1
kind: CephCluster
metadata:
  name: rook-ceph
  namespace: rook-ceph
spec:
  cephVersion:
    # For the latest ceph images, see https://hub.docker.com/r/ceph/ceph/tags
    image: ceph/ceph:v13.2.4-20190109
  dataDirHostPath: /var/lib/rook
  dashboard:
    enabled: true
  mon:
    count: 3
    allowMultiplePerNode: true
  storage:
    useAllNodes: true
    useAllDevices: false
    config:
      databaseSizeMB: "1024"
      journalSizeMB: "1024"

Create the cluster:

kubectl create -f cluster.yaml

Use kubectl to list pods in the rook namespace. You should be able to see the following pods once they are all running. The number of osd pods will depend on the number of nodes in the cluster and the number of devices and directories configured.

$ kubectl -n rook-ceph get pod
NAME                                   READY     STATUS      RESTARTS   AGE
rook-ceph-mgr-a-9c44495df-ln9sq        1/1       Running     0          1m
rook-ceph-mon-a-69fb9c78cd-58szd       1/1       Running     0          2m
rook-ceph-mon-b-cf4ddc49c-c756f        1/1       Running     0          2m
rook-ceph-mon-c-5b467747f4-8cbmv       1/1       Running     0          2m
rook-ceph-osd-0-f6549956d-6z294        1/1       Running     0          1m
rook-ceph-osd-1-5b96b56684-r7zsp       1/1       Running     0          1m
rook-ceph-osd-prepare-mynode-ftt57     0/1       Completed   0          1m

Storage

For a walkthrough of the three types of storage exposed by Rook, see the guides for:

Block: Create block storage to be consumed by a pod
Object: Create an object store that is accessible inside or outside the Kubernetes cluster
Shared File System: Create a file system to be shared across multiple pods

Ceph Dashboard

Ceph has a dashboard in which you can view the status of your cluster. Please see the dashboard guide for more details.

Tools

We have created a toolbox container that contains the full suite of Ceph clients for debugging and troubleshooting your Rook cluster. Please see the toolbox readme for setup and usage information. Also see our advanced configuration document for helpful maintenance and tuning examples.

Monitoring

Each Rook cluster has some built in metrics collectors/exporters for monitoring with Prometheus. To learn how to set up monitoring for your Rook cluster, you can follow the steps in the monitoring guide.

Teardown

When you are done with the test cluster, see these instructions to clean up the cluster.