K8S学习笔记之k8s使用ceph实现动态持久化存储
0x00 概述
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
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
0x01 部署K8S和Ceph
部署k8s
部署ceph
0x02 在k8s集群中配置使用ceph
2.1 使用Ceph RBD
2.1.1 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<<EOF 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
2.1.2 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<<EOF 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
2.1.3 测试使用
# 创建pvc测试 cat >ceph-rdb-pvc-test.yaml<<EOF 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<<EOF 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
0x03 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 github.com/kubernetes-… centos7升级内核
3.1 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
3.2 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<<EOF 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
3.3 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=$CEPH_ADMIN_SECRET \ --namespace=kube-system # 查看 secret kubectl get secret ceph-secret -n kube-system -o yaml # 配置 StorageClass cat >storageclass-cephfs.yaml<<EOF kind: StorageClass apiVersion: storage.k8s.io/v1 metadata: name: dynamic-cephfs provisioner: ceph.com/cephfs parameters: monitors: 11.11.11.111:6789,11.11.11.112:6789,11.11.11.113:6789 adminId: admin adminSecretName: ceph-secret adminSecretNamespace: "kube-system" claimRoot: /volumes/kubernetes EOF # 创建 kubectl apply -f storageclass-cephfs.yaml # 查看 kubectl get sc
3.4 测试使用
# 创建pvc测试 cat >cephfs-pvc-test.yaml<<EOF kind: PersistentVolumeClaim apiVersion: v1 metadata: name: cephfs-claim spec: accessModes: - ReadWriteOnce storageClassName: dynamic-cephfs resources: requests: storage: 2Gi EOF kubectl apply -f cephfs-pvc-test.yaml # 查看 kubectl get pvc kubectl get pv # 创建 nginx pod 挂载测试 cat >nginx-pod.yaml<<EOF apiVersion: v1 kind: Pod metadata: name: nginx-pod1 labels: name: nginx-pod1 spec: containers: - name: nginx-pod1 image: nginx:alpine ports: - name: web containerPort: 80 volumeMounts: - name: cephfs mountPath: /usr/share/nginx/html volumes: - name: cephfs persistentVolumeClaim: claimName: cephfs-claim EOF kubectl apply -f nginx-pod.yaml # 查看 kubectl get pods -o wide # 修改文件内容 kubectl exec -ti nginx-pod1 -- /bin/sh -c 'echo Hello World from CephFS!!! > /usr/share/nginx/html/index.html' # 访问测试 POD_ID=$(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
参考1
参考2
