k8s-ceph-rbd

k8s使用ceph实现动态持久化存储 https://juejin.im/post/5b766b5bf265da27e36efdfa
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2018.08.17 14:37* 字数 435 阅读 3432评论 1喜欢 3
简介
本文章介绍如何使用ceph为k8s提供动态申请pv的功能。ceph提供底层存储功能，cephfs方式支持k8s的pv的3种访问模式ReadWriteOnce，ReadOnlyMany ，ReadWriteMany ，RBD支持ReadWriteOnce，ReadOnlyMany两种模式

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访问模式只是能力描述，并不是强制执行的，对于没有按pvc声明的方式使用pv，存储提供者应该负责访问时的运行错误。例如如果设置pvc的访问模式为ReadOnlyMany ，pod挂载后依然可写，如果需要真正的不可写，申请pvc是需要指定 readOnly: true 参数

部署
部署k8s
centos7使用kubeadm安装k8s-1.11版本

部署ceph
centos7安装ceph分布式存储集群

在k8s集群中配置使用ceph
使用Ceph RBD
使用kubeadm安装集群的额外配置

如果使用kubeadm部署的集群需要这些额外的步骤

由于使用动态存储时 controller-manager 需要使用 rbd 命令创建 image

所以 controller-manager 需要使用 rbd 命令

由于官方controller-manager镜像里没有rbd命令

如果没使用如下方式会报错无法成功创建pvc

相关 issue https://github.com/kubernetes/kubernetes/issues/38923

cat >external-storage-rbd-provisioner.yaml<apiVersion: v1
kind: ServiceAccount
metadata:
name: rbd-provisioner
namespace: kube-system

kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: rbd-provisioner
rules:

• apiGroups: [""]
  resources: ["persistentvolumes"]
  verbs: ["get", "list", "watch", "create", "delete"]
• apiGroups: [""]
  resources: ["persistentvolumeclaims"]
  verbs: ["get", "list", "watch", "update"]
• apiGroups: ["storage.k8s.io"]
  resources: ["storageclasses"]
  verbs: ["get", "list", "watch"]
• apiGroups: [""]
  resources: ["events"]
  verbs: ["create", "update", "patch"]
• apiGroups: [""]
  resources: ["endpoints"]
  verbs: ["get", "list", "watch", "create", "update", "patch"]

• apiGroups: [""]
  resources: ["services"]
  resourceNames: ["kube-DNS"]
  verbs: ["list", "get"]

  kind: ClusterRoleBinding
  apiVersion: rbac.authorization.k8s.io/v1
  metadata:
  name: rbd-provisioner
  subjects:

• kind: ServiceAccount
  name: rbd-provisioner
  namespace: kube-system
  roleRef:
  kind: ClusterRole
  name: rbd-provisioner
  apiGroup: rbac.authorization.k8s.io

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
name: rbd-provisioner
namespace: kube-system
rules:

• apiGroups: [""]
  resources: ["secrets"]
  verbs: ["get"]

  apiVersion: rbac.authorization.k8s.io/v1
  kind: RoleBinding
  metadata:
  name: rbd-provisioner
  namespace: kube-system
  roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: rbd-provisioner
  subjects:

• kind: ServiceAccount
  name: rbd-provisioner
  namespace: kube-system

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: rbd-provisioner
namespace: kube-system
spec:
replicas: 1
strategy:
type: Recreate
template:
metadata:
labels:
app: rbd-provisioner
spec:
containers:

• name: rbd-provisioner
  image: "quay.io/external_storage/rbd-provisioner:v2.0.0-k8s1.11"
  env:
  • name: PROVISIONER_NAME
    value: ceph.com/rbd
    serviceAccount: rbd-provisioner
    EOF
    kubectl apply -f external-storage-rbd-provisioner.yaml

查看状态 等待running之后 再进行后续的操作

kubectl get pod -n kube-system
配置 storageclass

在k8s集群中所有节点安装 ceph-common

需要使用kubelet使用rdb命令map附加rbd创建的image

yum install -y ceph-common

创建 osd pool 在ceph的mon或者admin节点

ceph osd pool create kube 4096
ceph osd pool ls

创建k8s访问ceph的用户 在ceph的mon或者admin节点

ceph auth get-or-create client.kube mon 'allow r' osd 'allow class-read object_prefix rbd_children, allow rwx pool=kube' -o ceph.client.kube.keyring

查看key 在ceph的mon或者admin节点

ceph auth get-key client.admin
ceph auth get-key client.kube

创建 admin secret

CEPH_ADMIN_SECRET 替换为 client.admin 获取到的key

export CEPH_ADMIN_SECRET='AQBBAnRbSiSOFxAAEZXNMzYV6hsceccYLhzdWw=='
kubectl create secret generic ceph-secret --type="kubernetes.io/rbd" \
--from-literal=key=$CEPH_ADMIN_SECRET \
--namespace=kube-system

在 default 命名空间创建pvc用于访问ceph的 secret

CEPH_KUBE_SECRET 替换为 client.kube 获取到的key

export CEPH_KUBE_SECRET='AQBZK3VbTN/QOBAAIYi6CRLQcVevW5HM8lunOg=='
kubectl create secret generic ceph-user-secret --type="kubernetes.io/rbd" \
--from-literal=key=$CEPH_KUBE_SECRET \
--namespace=default

查看 secret

kubectl get secret ceph-user-secret -o yaml
kubectl get secret ceph-secret -n kube-system -o yaml

配置 StorageClass

如果使用kubeadm创建的集群 provisioner 使用如下方式

provisioner: ceph.com/rbd

cat >storageclass-ceph-rdb.yaml<kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: dynamic-ceph-rdb
provisioner: ceph.com/rbd

provisioner: kubernetes.io/rbd

parameters:
monitors: 11.11.11.111:6789,11.11.11.112:6789,11.11.11.113:6789
adminId: admin
adminSecretName: ceph-secret
adminSecretNamespace: kube-system
pool: kube
userId: kube
userSecretName: ceph-user-secret
fsType: ext4
imageFormat: "2"
imageFeatures: "layering"
EOF

创建

kubectl apply -f storageclass-ceph-rdb.yaml

查看

kubectl get sc
测试使用

创建pvc测试

cat >ceph-rdb-pvc-test.yaml<kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: ceph-rdb-claim
spec:
accessModes:

• ReadWriteOnce
  storageClassName: dynamic-ceph-rdb
  resources:
  requests:
  storage: 2Gi
  EOF
  kubectl apply -f ceph-rdb-pvc-test.yaml

查看

kubectl get pvc
kubectl get pv

创建 nginx pod 挂载测试

cat >nginx-pod.yaml<apiVersion: v1
kind: Pod
metadata:
name: nginx-pod1
labels:
name: nginx-pod1
spec:
containers:

• name: nginx-pod1
  image: nginx:alpine
  ports:
  • name: web
    containerPort: 80
    volumeMounts:
  • name: ceph-rdb
    mountPath: /usr/share/nginx/html
    volumes:
• name: ceph-rdb
  persistentVolumeClaim:
  claimName: ceph-rdb-claim
  EOF
  kubectl apply -f nginx-pod.yaml

查看

kubectl get pods -o wide

修改文件内容

kubectl exec -ti nginx-pod1 -- /bin/sh -c 'echo Hello World from Ceph RBD!!! > /usr/share/nginx/html/index.html'

访问测试

POD_ID=$(kubectl get pods -o wide | grep nginx-pod1 | awk '{print $(NF-1)}')
curl http://$POD_ID

清理

kubectl delete -f nginx-pod.yaml
kubectl delete -f ceph-rdb-pvc-test.yaml
使用 CephFS
linux内核需要4.10+，否则会出现无法正常使用的问题，详细issue信息 https://github.com/kubernetes-incubator/external-storage/issues/345
centos7升级内核

在ceph集群创建CephFS

如下操作在ceph的mon或者admin节点

CephFS需要使用两个Pool来分别存储数据和元数据

ceph osd pool create fs_data 128
ceph osd pool create fs_metadata 128
ceph osd lspools

创建一个CephFS

ceph fs new cephfs fs_metadata fs_data

查看

ceph fs ls
部署cephfs-provisioner

官方没有cephfs动态卷支持

使用社区提供的cephfs-provisioner

cat >external-storage-cephfs-provisioner.yaml<apiVersion: v1
kind: ServiceAccount
metadata:
name: cephfs-provisioner
namespace: kube-system

kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: cephfs-provisioner
rules:

• apiGroups: [""]
  resources: ["persistentvolumes"]
  verbs: ["get", "list", "watch", "create", "delete"]
• apiGroups: [""]
  resources: ["persistentvolumeclaims"]
  verbs: ["get", "list", "watch", "update"]
• apiGroups: ["storage.k8s.io"]
  resources: ["storageclasses"]
  verbs: ["get", "list", "watch"]
• apiGroups: [""]
  resources: ["events"]
  verbs: ["create", "update", "patch"]
• apiGroups: [""]
  resources: ["endpoints"]
  verbs: ["get", "list", "watch", "create", "update", "patch"]

• apiGroups: [""]
  resources: ["secrets"]
  verbs: ["create", "get", "delete"]

  kind: ClusterRoleBinding
  apiVersion: rbac.authorization.k8s.io/v1
  metadata:
  name: cephfs-provisioner
  subjects:

• kind: ServiceAccount
  name: cephfs-provisioner
  namespace: kube-system
  roleRef:
  kind: ClusterRole
  name: cephfs-provisioner
  apiGroup: rbac.authorization.k8s.io

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
name: cephfs-provisioner
namespace: kube-system
rules:

• apiGroups: [""]
  resources: ["secrets"]
  verbs: ["create", "get", "delete"]

  apiVersion: rbac.authorization.k8s.io/v1
  kind: RoleBinding
  metadata:
  name: cephfs-provisioner
  namespace: kube-system
  roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: cephfs-provisioner
  subjects:

  • kind: ServiceAccount
    name: cephfs-provisioner
    namespace: kube-system

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: cephfs-provisioner
namespace: kube-system
spec:
replicas: 1
strategy:
type: Recreate
template:
metadata:
labels:
app: cephfs-provisioner
spec:
containers:

• name: cephfs-provisioner
  image: "quay.io/external_storage/cephfs-provisioner:v2.0.0-k8s1.11"
  env:
  • name: PROVISIONER_NAME
    value: ceph.com/cephfs
    command:
  • "/usr/local/bin/cephfs-provisioner"
    args:
  • "-id=cephfs-provisioner-1"
    serviceAccount: cephfs-provisioner
    EOF
    kubectl apply -f external-storage-cephfs-provisioner.yaml

查看状态 等待running之后 再进行后续的操作

kubectl get pod -n kube-system
配置 storageclass

查看key 在ceph的mon或者admin节点

ceph auth get-key client.admin

创建 admin secret

CEPH_ADMIN_SECRET 替换为 client.admin 获取到的key

如果在测试 ceph rbd 方式已经添加 可以略过此步骤

export CEPH_ADMIN_SECRET='AQBBAnRbSiSOFxAAEZXNMzYV6hsceccYLhzdWw=='
kubectl create secret generic ceph-secret --type="kubernetes.io/rbd" \
--from-literal=key=$CEPH_ADMIN_SECRET \
--namespace=kube-system

查看 secret

kubectl get secret ceph-secret -n kube-system -o yaml

配置 StorageClass

cat >storageclass-cephfs.yaml<kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: dynamic-cephfs
provisioner: ceph.com/cephfs
parameters:
monitors: 11.11.11.111:6789,11.11.11.112:6789,11.11.11.113:6789
adminId: admin
adminSecretName: ceph-secret
adminSecretNamespace: "kube-system"
claimRoot: /volumes/kubernetes
EOF

创建

kubectl apply -f storageclass-cephfs.yaml

查看

kubectl get sc
测试使用

创建pvc测试

cat >cephfs-pvc-test.yaml<kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: cephfs-claim
spec:
accessModes:

• ReadWriteOnce
  storageClassName: dynamic-cephfs
  resources:
  requests:
  storage: 2Gi
  EOF
  kubectl apply -f cephfs-pvc-test.yaml

查看

kubectl get pvc
kubectl get pv

创建 nginx pod 挂载测试

cat >nginx-pod.yaml<apiVersion: v1
kind: Pod
metadata:
name: nginx-pod1
labels:
name: nginx-pod1
spec:
containers:

• name: nginx-pod1
  image: nginx:alpine
  ports:
  • name: web
    containerPort: 80
    volumeMounts:
  • name: cephfs
    mountPath: /usr/share/nginx/html
    volumes:
• name: cephfs
  persistentVolumeClaim:
  claimName: cephfs-claim
  EOF
  kubectl apply -f nginx-pod.yaml

查看

kubectl get pods -o wide

修改文件内容

kubectl exec -ti nginx-pod1 -- /bin/sh -c 'echo Hello World from CephFS!!! > /usr/share/nginx/html/index.html'

访问测试

POD_ID=$(kubectl get pods -o wide | grep nginx-pod1 | awk '{print $(NF-1)}')
curl http://$POD_ID

清理

kubectl delete -f nginx-pod.yaml
kubectl delete -f cephfs-pvc-test.yaml