323 lines
12 KiB
Markdown
323 lines
12 KiB
Markdown
# 用Helm托管安装Ceph集群并提供后端存储
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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。
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## 安装
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[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。
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## 当前的限制
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* Public网络和Cluster网络必须是同一个网络
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* 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
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* ceph-mgr只能运行1个replica
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## 安装并使用Helm
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可以按照此说明[instructions](https://github.com/kubernetes/helm/blob/master/docs/install.md)安装Helm。
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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。
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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）：
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```bash
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$ helm init
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```
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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：
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```bash
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$ helm serve &
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$ helm repo add local http://localhost:8879/charts
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```
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## 添加Ceph-Helm charts到本地repo
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```bash
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$ git clone https://github.com/ceph/ceph-helm
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$ cd ceph-helm/ceph
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$ make
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```
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## 配置Ceph集群
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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。
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```bash
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$ cat ~/ceph-overrides.yaml
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```
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```yaml
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network:
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public: 172.21.0.0/20
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cluster: 172.21.0.0/20
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osd_devices:
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- name: dev-sdd
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device: /dev/sdd
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zap: "1"
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- name: dev-sde
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device: /dev/sde
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zap: "1"
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storageclass:
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name: ceph-rbd
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pool: rbd
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user_id: k8s
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```
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**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。
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## 创建Ceph 集群的namespace
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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：
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```bash
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$ kubectl create namespace ceph
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```
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## 配置RBAC权限
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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：
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```bash
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$ kubectl create -f ~/ceph-helm/ceph/rbac.yaml
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```
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rbac.yaml文件假定Ceph集群将部署在ceph命名空间中。
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## 给Kubelet节点打标签
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需要设置以下标签才能部署Ceph集群：
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```
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ceph-mon=enabled
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ceph-mgr=enabled
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ceph-osd=enabled
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ceph-osd-device-<name>=enabled
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```
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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。
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每个 Ceph Monitor节点:
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```bash
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$ kubectl label node <nodename> ceph-mon=enabled ceph-mgr=enabled
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```
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每个 OSD node节点:
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```bash
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$ kubectl label node <nodename> ceph-osd=enabled ceph-osd-device-dev-sdb=enabled ceph-osd-device-dev-sdc=enabled
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```
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## Ceph 部署
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运行helm install命令来部署Ceph：
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```bash
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$ helm install --name=ceph local/ceph --namespace=ceph -f ~/ceph-overrides.yaml
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NAME: ceph
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LAST DEPLOYED: Wed Oct 18 22:25:06 2017
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NAMESPACE: ceph
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STATUS: DEPLOYED
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RESOURCES:
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==> v1/Secret
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NAME TYPE DATA AGE
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ceph-keystone-user-rgw Opaque 7 1s
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==> v1/ConfigMap
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NAME DATA AGE
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ceph-bin-clients 2 1s
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ceph-bin 24 1s
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ceph-etc 1 1s
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ceph-templates 5 1s
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==> v1/Service
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NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
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ceph-mon None <none> 6789/TCP 1s
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ceph-rgw 10.101.219.239 <none> 8088/TCP 1s
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==> v1beta1/DaemonSet
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NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE-SELECTOR AGE
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ceph-mon 3 3 0 3 0 ceph-mon=enabled 1s
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ceph-osd-dev-sde 3 3 0 3 0 ceph-osd-device-dev-sde=enabled,ceph-osd=enabled 1s
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ceph-osd-dev-sdd 3 3 0 3 0 ceph-osd-device-dev-sdd=enabled,ceph-osd=enabled 1s
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==> v1beta1/Deployment
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NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
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ceph-mds 1 1 1 0 1s
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ceph-mgr 1 1 1 0 1s
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ceph-mon-check 1 1 1 0 1s
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ceph-rbd-provisioner 2 2 2 0 1s
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ceph-rgw 1 1 1 0 1s
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==> v1/Job
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NAME DESIRED SUCCESSFUL AGE
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ceph-mgr-keyring-generator 1 0 1s
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ceph-mds-keyring-generator 1 0 1s
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ceph-osd-keyring-generator 1 0 1s
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ceph-rgw-keyring-generator 1 0 1s
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ceph-mon-keyring-generator 1 0 1s
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ceph-namespace-client-key-generator 1 0 1s
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ceph-storage-keys-generator 1 0 1s
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==> v1/StorageClass
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NAME TYPE
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ceph-rbd ceph.com/rbd
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```
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helm install的输出显示了将要部署的不同类型的资源。
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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：
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```yaml
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storageclass:
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name: ceph-rbd
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pool: rbd
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user_id: k8s
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user_secret_name: pvc-ceph-client-key
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image_format: "2"
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image_features: layering
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```
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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：
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```bash
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$ kubectl -n ceph get pods
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NAME READY STATUS RESTARTS AGE
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ceph-mds-3804776627-976z9 0/1 Pending 0 1m
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ceph-mgr-3367933990-b368c 1/1 Running 0 1m
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ceph-mon-check-1818208419-0vkb7 1/1 Running 0 1m
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ceph-mon-cppdk 3/3 Running 0 1m
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ceph-mon-t4stn 3/3 Running 0 1m
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ceph-mon-vqzl0 3/3 Running 0 1m
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ceph-osd-dev-sdd-6dphp 1/1 Running 0 1m
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ceph-osd-dev-sdd-6w7ng 1/1 Running 0 1m
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ceph-osd-dev-sdd-l80vv 1/1 Running 0 1m
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ceph-osd-dev-sde-6dq6w 1/1 Running 0 1m
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ceph-osd-dev-sde-kqt0r 1/1 Running 0 1m
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ceph-osd-dev-sde-lp2pf 1/1 Running 0 1m
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ceph-rbd-provisioner-2099367036-4prvt 1/1 Running 0 1m
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ceph-rbd-provisioner-2099367036-h9kw7 1/1 Running 0 1m
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ceph-rgw-3375847861-4wr74 0/1 Pending 0 1m
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```
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**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：
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```bash
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$ kubectl -n ceph exec -ti ceph-mon-cppdk -c ceph-mon -- ceph -s
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cluster:
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id: e8f9da03-c2d2-4ad3-b807-2a13d0775504
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health: HEALTH_OK
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services:
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mon: 3 daemons, quorum mira115,mira110,mira109
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mgr: mira109(active)
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osd: 6 osds: 6 up, 6 in
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data:
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pools: 0 pools, 0 pgs
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objects: 0 objects, 0 bytes
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usage: 644 MB used, 5555 GB / 5556 GB avail
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pgs:
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```
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## 配置一个POD以便从Ceph申请使用一个持久卷
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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：
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```bash
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$ kubectl -n ceph exec -ti ceph-mon-cppdk -c ceph-mon -- bash
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# ceph auth get-or-create-key client.k8s mon 'allow r' osd 'allow rwx pool=rbd' | base64
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QVFCLzdPaFoxeUxCRVJBQUVEVGdHcE9YU3BYMVBSdURHUEU0T0E9PQo=
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# exit
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```
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编辑ceph namespace中存在的用户secret：
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```bash
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$ kubectl -n ceph edit secrets/pvc-ceph-client-key
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```
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将base64值复制到key位置的值并保存：:
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```yaml
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apiVersion: v1
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data:
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key: QVFCLzdPaFoxeUxCRVJBQUVEVGdHcE9YU3BYMVBSdURHUEU0T0E9PQo=
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kind: Secret
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metadata:
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creationTimestamp: 2017-10-19T17:34:04Z
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name: pvc-ceph-client-key
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namespace: ceph
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resourceVersion: "8665522"
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selfLink: /api/v1/namespaces/ceph/secrets/pvc-ceph-client-key
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uid: b4085944-b4f3-11e7-add7-002590347682
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type: kubernetes.io/rbd
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```
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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：
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```bash
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$ kubectl -n ceph get secrets/pvc-ceph-client-key -o json | jq '.metadata.namespace = "default"' | kubectl create -f -
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secret "pvc-ceph-client-key" created
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$ kubectl get secrets
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NAME TYPE DATA AGE
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default-token-r43wl kubernetes.io/service-account-token 3 61d
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pvc-ceph-client-key kubernetes.io/rbd 1 20s
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```
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创建并初始化RBD池：
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```bash
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$ kubectl -n ceph exec -ti ceph-mon-cppdk -c ceph-mon -- ceph osd pool create rbd 256
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pool 'rbd' created
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$ kubectl -n ceph exec -ti ceph-mon-cppdk -c ceph-mon -- rbd pool init rbd
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```
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**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。
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**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。
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创建一个PVC：
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```bash
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$ cat pvc-rbd.yaml
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```
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```yaml
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kind: PersistentVolumeClaim
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apiVersion: v1
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metadata:
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name: ceph-pvc
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spec:
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accessModes:
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- ReadWriteOnce
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resources:
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requests:
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storage: 20Gi
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storageClassName: ceph-rbd
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```
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```bash
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$ kubectl create -f pvc-rbd.yaml
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persistentvolumeclaim "ceph-pvc" created
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$ kubectl get pvc
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NAME STATUS VOLUME CAPACITY ACCESSMODES STORAGECLASS AGE
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ceph-pvc Bound pvc-1c2ada50-b456-11e7-add7-002590347682 20Gi RWO ceph-rbd 3s
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```
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检查集群上是否已创建RBD：
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```bash
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$ kubectl -n ceph exec -ti ceph-mon-cppdk -c ceph-mon -- rbd ls
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kubernetes-dynamic-pvc-1c2e9442-b456-11e7-9bd2-2a4159ce3915
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$ kubectl -n ceph exec -ti ceph-mon-cppdk -c ceph-mon -- rbd info kubernetes-dynamic-pvc-1c2e9442-b456-11e7-9bd2-2a4159ce3915
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rbd image 'kubernetes-dynamic-pvc-1c2e9442-b456-11e7-9bd2-2a4159ce3915':
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size 20480 MB in 5120 objects
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order 22 (4096 kB objects)
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block_name_prefix: rbd_data.10762ae8944a
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format: 2
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features: layering
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flags:
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create_timestamp: Wed Oct 18 22:45:59 2017
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```
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创建一个使用此PVC的Pod：
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```bash
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$ cat pod-with-rbd.yaml
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```
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```yaml
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kind: Pod
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apiVersion: v1
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metadata:
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name: mypod
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spec:
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containers:
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- name: busybox
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image: busybox
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command:
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- sleep
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- "3600"
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volumeMounts:
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- mountPath: "/mnt/rbd"
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name: vol1
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volumes:
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- name: vol1
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persistentVolumeClaim:
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claimName: ceph-pvc
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```
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```bash
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$ kubectl create -f pod-with-rbd.yaml
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pod "mypod" created
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```
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检查Pod：
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```bash
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$ kubectl get pods
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NAME READY STATUS RESTARTS AGE
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mypod 1/1 Running 0 17s
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$ kubectl exec mypod -- mount | grep rbd
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/dev/rbd0 on /mnt/rbd type ext4 (rw,relatime,stripe=1024,data=ordered)
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```
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## 日志
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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。
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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：
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```bash
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$ kubectl -n ceph logs ceph-mon-cppdk -c cluster-log-tailer
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```
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