# 用Helm托管安装Ceph集群并提供后端存储 本文翻译自Ceph[官方文档](http://docs.ceph.com/docs/master/start/kube-helm/),括号内的内容为注释。 ## 安装 [ceph-helm ](https://github.com/ceph/ceph-helm/)项目可让你在Kubernetes 环境以托管方式部署Ceph . 本文档假定Kubernetes 环境已经可用。 ## 当前的限制 * Public网络和Cluster网络必须是同一个网络 * 如果 storage class 用户标识不是admin, 则必须在Ceph集群中手动创建用户并在Kubernetes中创建其secret * ceph-mgr只能运行1个replica ## 安装并使用Helm 可以按照此说明[instructions](https://github.com/kubernetes/helm/blob/master/docs/install.md)安装Helm。 Helm通过从本地读取Kubernetes配置文件来查找Kubernetes集群; 确保文件已下载和且helm客户端可以访问。 Kubernetes群集必须配置并运行Tiller服务器,并且须将本地Helm客户端网络可达。查看[init](https://github.com/kubernetes/helm/blob/master/docs/helm/helm_init.md)的Helm文档获取帮助。要在本地运行Tiller并将Helm连接到它,请运行如下命令(此命令会在Kubernetes集群部署一个tiller实例): ```bash $ helm init ``` ceph-helm项目默认使用本地的Helm repo来存储charts。要启动本地Helm repo服务器,请运行: ```bash $ helm serve & $ helm repo add local http://localhost:8879/charts ``` ## 添加Ceph-Helm charts到本地repo ```bash $ git clone https://github.com/ceph/ceph-helm $ cd ceph-helm/ceph $ make ``` ## 配置Ceph集群 创建一个包含Ceph配置的ceph-overrides.yaml文件。这个文件可能存在于任何地方,本文档默认此文件在用户的home目录中。 ```bash $ cat ~/ceph-overrides.yaml ``` ```yaml network: public: 172.21.0.0/20 cluster: 172.21.0.0/20 osd_devices: - name: dev-sdd device: /dev/sdd zap: "1" - name: dev-sde device: /dev/sde zap: "1" storageclass: name: ceph-rbd pool: rbd user_id: k8s ``` **注意** 如果未设置日志(journal)设备,它将与device设备同位置。另ceph-helm/ceph/ceph/values.yaml文件包含所有可配置的选项。 ## 创建Ceph 集群的namespace 默认情况下,ceph-helm组件在Kubernetes的ceph namespace中运行。如果要自定义,请自定义namespace的名称,默认namespace请运行: ```bash $ kubectl create namespace ceph ``` ## 配置RBAC权限 Kubernetes> = v1.6使RBAC成为默认的admission controller。ceph-helm要为每个组件提供RBAC角色和权限: ```bash $ kubectl create -f ~/ceph-helm/ceph/rbac.yaml ``` rbac.yaml文件假定Ceph集群将部署在ceph命名空间中。 ## 给Kubelet节点打标签 需要设置以下标签才能部署Ceph集群: ``` ceph-mon=enabled ceph-mgr=enabled ceph-osd=enabled ceph-osd-device-=enabled ``` ceph-osd-device-标签是基于我们的ceph-overrides.yaml中定义的osd_devices名称值创建的。从我们下面的例子中,我们将得到以下两个标签:ceph-osd-device-dev-sdb和ceph-osd-device-dev-sdc。 每个 Ceph Monitor节点: ```bash $ kubectl label node ceph-mon=enabled ceph-mgr=enabled ``` 每个 OSD node节点: ```bash $ kubectl label node ceph-osd=enabled ceph-osd-device-dev-sdb=enabled ceph-osd-device-dev-sdc=enabled ``` ## Ceph 部署 运行helm install命令来部署Ceph: ```bash $ helm install --name=ceph local/ceph --namespace=ceph -f ~/ceph-overrides.yaml NAME: ceph LAST DEPLOYED: Wed Oct 18 22:25:06 2017 NAMESPACE: ceph STATUS: DEPLOYED RESOURCES: ==> v1/Secret NAME TYPE DATA AGE ceph-keystone-user-rgw Opaque 7 1s ==> v1/ConfigMap NAME DATA AGE ceph-bin-clients 2 1s ceph-bin 24 1s ceph-etc 1 1s ceph-templates 5 1s ==> v1/Service NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE ceph-mon None 6789/TCP 1s ceph-rgw 10.101.219.239 8088/TCP 1s ==> v1beta1/DaemonSet NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE-SELECTOR AGE ceph-mon 3 3 0 3 0 ceph-mon=enabled 1s ceph-osd-dev-sde 3 3 0 3 0 ceph-osd-device-dev-sde=enabled,ceph-osd=enabled 1s ceph-osd-dev-sdd 3 3 0 3 0 ceph-osd-device-dev-sdd=enabled,ceph-osd=enabled 1s ==> v1beta1/Deployment NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE ceph-mds 1 1 1 0 1s ceph-mgr 1 1 1 0 1s ceph-mon-check 1 1 1 0 1s ceph-rbd-provisioner 2 2 2 0 1s ceph-rgw 1 1 1 0 1s ==> v1/Job NAME DESIRED SUCCESSFUL AGE ceph-mgr-keyring-generator 1 0 1s ceph-mds-keyring-generator 1 0 1s ceph-osd-keyring-generator 1 0 1s ceph-rgw-keyring-generator 1 0 1s ceph-mon-keyring-generator 1 0 1s ceph-namespace-client-key-generator 1 0 1s ceph-storage-keys-generator 1 0 1s ==> v1/StorageClass NAME TYPE ceph-rbd ceph.com/rbd ``` helm install的输出显示了将要部署的不同类型的资源。 将使用ceph-rbd-provisioner Pod创建ceph.com/rbd类型的名为ceph-rbd的StorageClass。这允许创建PVC时自动提供RBD。第一次挂载时,RBD设备将被格式化(format)。所有RBD设备都将使用ext4文件系统。ceph.com/rbd不支持fsType选项。默认情况下,RBD将使用镜像格式2和镜像分层特性。可以在values文件中覆盖以下storageclass的默认值: ```yaml storageclass: name: ceph-rbd pool: rbd user_id: k8s user_secret_name: pvc-ceph-client-key image_format: "2" image_features: layering ``` 使用下面的命令检查所有Pod是否正常运行。这可能需要几分钟时间: ```bash $ kubectl -n ceph get pods NAME READY STATUS RESTARTS AGE ceph-mds-3804776627-976z9 0/1 Pending 0 1m ceph-mgr-3367933990-b368c 1/1 Running 0 1m ceph-mon-check-1818208419-0vkb7 1/1 Running 0 1m ceph-mon-cppdk 3/3 Running 0 1m ceph-mon-t4stn 3/3 Running 0 1m ceph-mon-vqzl0 3/3 Running 0 1m ceph-osd-dev-sdd-6dphp 1/1 Running 0 1m ceph-osd-dev-sdd-6w7ng 1/1 Running 0 1m ceph-osd-dev-sdd-l80vv 1/1 Running 0 1m ceph-osd-dev-sde-6dq6w 1/1 Running 0 1m ceph-osd-dev-sde-kqt0r 1/1 Running 0 1m ceph-osd-dev-sde-lp2pf 1/1 Running 0 1m ceph-rbd-provisioner-2099367036-4prvt 1/1 Running 0 1m ceph-rbd-provisioner-2099367036-h9kw7 1/1 Running 0 1m ceph-rgw-3375847861-4wr74 0/1 Pending 0 1m ``` **注意** 因为我们没有用ceph-rgw = enabled或ceph-mds = enabled 给节点打标签(ceph对象存储特性需要ceph-rgw,cephfs特性需要ceph-mds),因此MDS和RGW Pod都处于pending状态,一旦其他Pod都在运行状态,请用如下命令从某个MON节点检查Ceph的集群状态: ```bash $ kubectl -n ceph exec -ti ceph-mon-cppdk -c ceph-mon -- ceph -s cluster: id: e8f9da03-c2d2-4ad3-b807-2a13d0775504 health: HEALTH_OK services: mon: 3 daemons, quorum mira115,mira110,mira109 mgr: mira109(active) osd: 6 osds: 6 up, 6 in data: pools: 0 pools, 0 pgs objects: 0 objects, 0 bytes usage: 644 MB used, 5555 GB / 5556 GB avail pgs: ``` ## 配置一个POD以便从Ceph申请使用一个持久卷 为〜/ ceph-overwrite.yaml中定义的k8s用户创建一个密钥环,并将其转换为base64: ```bash $ kubectl -n ceph exec -ti ceph-mon-cppdk -c ceph-mon -- bash # ceph auth get-or-create-key client.k8s mon 'allow r' osd 'allow rwx pool=rbd' | base64 QVFCLzdPaFoxeUxCRVJBQUVEVGdHcE9YU3BYMVBSdURHUEU0T0E9PQo= # exit ``` 编辑ceph namespace中存在的用户secret: ```bash $ kubectl -n ceph edit secrets/pvc-ceph-client-key ``` 将base64值复制到key位置的值并保存:: ```yaml apiVersion: v1 data: key: QVFCLzdPaFoxeUxCRVJBQUVEVGdHcE9YU3BYMVBSdURHUEU0T0E9PQo= kind: Secret metadata: creationTimestamp: 2017-10-19T17:34:04Z name: pvc-ceph-client-key namespace: ceph resourceVersion: "8665522" selfLink: /api/v1/namespaces/ceph/secrets/pvc-ceph-client-key uid: b4085944-b4f3-11e7-add7-002590347682 type: kubernetes.io/rbd ``` 我们创建一个在default namespace中使用RBD的Pod。将用户secret从ceph namespace复制到default namespace: ```bash $ kubectl -n ceph get secrets/pvc-ceph-client-key -o json | jq '.metadata.namespace = "default"' | kubectl create -f - secret "pvc-ceph-client-key" created $ kubectl get secrets NAME TYPE DATA AGE default-token-r43wl kubernetes.io/service-account-token 3 61d pvc-ceph-client-key kubernetes.io/rbd 1 20s ``` 创建并初始化RBD池: ```bash $ kubectl -n ceph exec -ti ceph-mon-cppdk -c ceph-mon -- ceph osd pool create rbd 256 pool 'rbd' created $ kubectl -n ceph exec -ti ceph-mon-cppdk -c ceph-mon -- rbd pool init rbd ``` **重要** 重要的 Kubernetes使用RBD内核模块将RBD映射到主机。Luminous需要CRUSH_TUNABLES 5(Jewel)。这些可调参数的最小内核版本是4.5。如果您的内核不支持这些可调参数,请运行ceph osd crush tunables hammer。 **重要** 由于RBD映射到主机系统上。主机需要能够解析由kube-dns服务管理的ceph-mon.ceph.svc.cluster.local名称。要获得kube-dns服务的IP地址,运行kubectl -n kube-system get svc/kube-dns。 创建一个PVC: ```bash $ cat pvc-rbd.yaml ``` ```yaml kind: PersistentVolumeClaim apiVersion: v1 metadata: name: ceph-pvc spec: accessModes: - ReadWriteOnce resources: requests: storage: 20Gi storageClassName: ceph-rbd ``` ```bash $ kubectl create -f pvc-rbd.yaml persistentvolumeclaim "ceph-pvc" created $ kubectl get pvc NAME STATUS VOLUME CAPACITY ACCESSMODES STORAGECLASS AGE ceph-pvc Bound pvc-1c2ada50-b456-11e7-add7-002590347682 20Gi RWO ceph-rbd 3s ``` 检查集群上是否已创建RBD: ```bash $ kubectl -n ceph exec -ti ceph-mon-cppdk -c ceph-mon -- rbd ls kubernetes-dynamic-pvc-1c2e9442-b456-11e7-9bd2-2a4159ce3915 $ kubectl -n ceph exec -ti ceph-mon-cppdk -c ceph-mon -- rbd info kubernetes-dynamic-pvc-1c2e9442-b456-11e7-9bd2-2a4159ce3915 rbd image 'kubernetes-dynamic-pvc-1c2e9442-b456-11e7-9bd2-2a4159ce3915': size 20480 MB in 5120 objects order 22 (4096 kB objects) block_name_prefix: rbd_data.10762ae8944a format: 2 features: layering flags: create_timestamp: Wed Oct 18 22:45:59 2017 ``` 创建一个使用此PVC的Pod: ```bash $ cat pod-with-rbd.yaml ``` ```yaml kind: Pod apiVersion: v1 metadata: name: mypod spec: containers: - name: busybox image: busybox command: - sleep - "3600" volumeMounts: - mountPath: "/mnt/rbd" name: vol1 volumes: - name: vol1 persistentVolumeClaim: claimName: ceph-pvc ``` ```bash $ kubectl create -f pod-with-rbd.yaml pod "mypod" created ``` 检查Pod: ```bash $ kubectl get pods NAME READY STATUS RESTARTS AGE mypod 1/1 Running 0 17s $ kubectl exec mypod -- mount | grep rbd /dev/rbd0 on /mnt/rbd type ext4 (rw,relatime,stripe=1024,data=ordered) ``` ## 日志 可以通过kubectl logs [-f]命令访问OSD和Monitor日志。Monitors有多个日志记录流,每个流都可以从ceph-mon Pod中的容器访问。 在ceph-mon Pod中有3个容器运行:ceph-mon,相当于物理机上的ceph-mon.hostname.log,cluster-audit-log-tailer相当于物理机上的ceph.audit.log,cluster-log-tailer相当于物理机上的ceph.log或ceph -w。每个容器都可以通过--container或-c选项访问。例如,要访问cluster-tail-log,可以运行: ```bash $ kubectl -n ceph logs ceph-mon-cppdk -c cluster-log-tailer ```