ceph对接k8s storage class

简介

对接ceph的rbd和cephfs到k8s中提供持久化存储

环境

主机名	IP	role	操作系统
ceph-01	172.16.31.11	mon osd	CentOS7.8
ceph-02	172.16.31.12	Osd	CentOS7.8
ceph-03	172.16.31.13	osd	CentOS7.8

这个是官网的图

步骤

安装ceph

主机名设置

## ceph-01
hostnamectl set-hostname ceph-01
## ceph-02
hostnamectl set-hostname ceph-01
## ceph-03
hostnamectl set-hostname ceph-01

添加主机映射

cat << EOF >> /etc/hosts
172.16.31.11 ceph-01
172.16.31.12 ceph-02
172.16.31.13 ceph-03
EOF

关闭防火墙

systemctl stop firewalld && systemctl stop firewalld
setenforce 0 && sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/selinux/config
iptables -F && iptables -X && iptables -Z

时间同步

yum install -y ntpdate
ntpdate

ssh无密钥访问

## ceph-01节点执行
ssh-keygen 

ssh-copy-id ceph-01

ssh-copy-id ceph-02

ssh-copy-id ceph-03

准备repo

yum install epel-release -y
cat << EOF > /etc/yum.repos.d/ceph-deploy.repo
[ceph-noarch]
name=Ceph noarch packages
baseurl=https://download.ceph.com/rpm-luminous/el7/noarch
enabled=1
gpgcheck=1
type=rpm-md
gpgkey=https://download.ceph.com/keys/release.asc
EOF

国内用户可以用阿里的仓库

wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo
cat << EOF > /etc/yum.repos.d/ceph-deploy.repo
[ceph-noarch]
name=Ceph noarch packages
baseurl=https://mirrors.aliyun.com/ceph/rpm-luminous/el7/noarch/
enabled=1
gpgcheck=0
EOF

安装ceph-deploy软件包

ceph-1节点

yum install ceph-deploy yum-plugin-priorities python2-pip bash-completion -y

其他节点安装

yum install yum-plugin-priorities python2-pip bash-completion -y

创建一个ceph目录

ceph-01节点

mkdir ceph-cluster
cd ceph-cluster

初始化ceph集群

ceph-deploy new ceph-01

（可选）修改网络接口

如果有两个网卡，可以将管理和存储网分离

public_network = 172.16.0.0/16
cluster_network = 192.168.31.0/24

安装ceph软件包

ceph-deploy install ceph-01 ceph-02 ceph-03

国内加速可以指定阿里云镜像地址，先在所有节点添加这个仓库

cat << EOF > /etc/yum.repos.d/ceph-luminous.repo
[ceph]
name=Ceph packages for x86_64
baseurl=http://mirrors.aliyun.com/ceph/rpm-luminous/el7/x86_64
enabled=1
gpgcheck=0
EOF

然后执行

ceph-deploy install ceph-01 ceph-02 ceph-03 --no-adjust-repos

创建mon

ceph-deploy mon create-initial

执行完后会创建*.keyring 密钥环

复制配置和秘钥到对应的节点上

ceph-deploy admin ceph-01 ceph-02 ceph-03

部署mgr

ceph-deploy mgr create ceph-01

mgr是ceph-12.x版本(luminous)新增的组件

部署osd

ceph-deploy osd create --data /dev/sdb ceph-01
ceph-deploy osd create --data /dev/sdb ceph-02
ceph-deploy osd create --data /dev/sdb ceph-03

检查集群状态

ceph health
ceph -s

测试

创建pool

ceph osd pool create test 8 8
echo `date` > date.txt
rados put test-object-1 date.txt --pool=test

上传到存储池中

echo `date` > date.txt
rados put test-object-1 date.txt --pool=test

查看存储池和对象映射

rados -p test ls
ceph osd map test test-object-1

删除

rados rm test-object-1 --pool=test
ceph osd pool rm test test --yes-i-really-really-mean-it

这里删不掉的话，需要添加这个配置

mon_allow_pool_delete = true

然后重启mon

ceph-deploy --overwrite-conf admin ceph-01 ceph-02 ceph-03
systemctl restart ceph-mon@ceph-01.service
## 再执行删除
ceph osd pool rm test test --yes-i-really-really-mean-it

ceph rbd对接kubernetes

参考github连接：https://kubernetes.io/zh/docs/concepts/storage/storage-classes/#ceph-rbd

创建pool

ceph osd pool create kube-pool 64 64

导入admin keyring

获取admin keyring

ceph auth get-key client.admin

将key换成上一步输出的结果

kubectl create secret generic ceph-secret  -n kube-system \
  --type="kubernetes.io/rbd" \
  --from-literal=key='AQDYuPZfdjykCxAAXApI8weHFiZdEPcoc8EaRA=='

创建 user secret

ceph auth add client.kube mon 'allow r' osd 'allow rwx pool=kube-pool'
ceph auth get-key client.kube
kubectl create secret generic ceph-secret-user -n kube-system  --from-literal=key='AQAH2vZfe8wWIhAA0w81hjSAoqmjayS5SmWuVQ=='  --type=kubernetes.io/rbd

创建StorageClass

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: ceph-rbd
provisioner: kubernetes.io/rbd
parameters:
  monitors: 172.16.31.11:6789
  adminId: admin
  adminSecretName: ceph-secret
  adminSecretNamespace: kube-system
  pool: kube-pool
  userId: kube
  userSecretName: ceph-secret-user
  userSecretNamespace: kube-system
  fsType: ext4
  imageFormat: "2"
  imageFeatures: "layering"

worker节点安装ceph-common

cat << EOF > /etc/yum.repos.d/ceph-luminous.repo
[ceph]
name=Ceph packages for x86_64
baseurl=http://mirrors.aliyun.com/ceph/rpm-luminous/el7/x86_64
enabled=1
gpgcheck=0
EOF
yum install -y ceph-common

创建PVC

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: rbd-1
  namespace: default
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
  storageClassName: ceph-rbd

创建deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: test-rbd
  name: test-rbd
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: test-rbd
  template:
    metadata:
      labels:
        app: test-rbd
    spec:
      containers:
      - image: zerchin/network
        imagePullPolicy: IfNotPresent
        name: test-rbd
        volumeMounts:
        - mountPath: /data
          name: rbd
      volumes:
      - name: rbd
        persistentVolumeClaim:
          claimName: rbd-1

常见问题

问题1：rbd未加载报错

MountVolume.WaitForAttach failed for volume "pvc-8d8a8ed9-bcdb-4de8-a725-9121fcb89c84" : rbd: map failed exit status 2, rbd output: libkmod: ERROR ../libkmod/libkmod.c:586 kmod_search_moddep: could not open moddep file '/lib/modules/4.4.247-1.el7.elrepo.x86_64/modules.dep.bin' modinfo: ERROR: Module alias rbd not found. modprobe: ERROR: ../libkmod/libkmod.c:586 kmod_search_moddep() could not open moddep file '/lib/modules/4.4.247-1.el7.elrepo.x86_64/modules.dep.bin' modprobe: FATAL: Module rbd not found in directory /lib/modules/4.4.247-1.el7.elrepo.x86_64 rbd: failed to load rbd kernel module (1) rbd: sysfs write failed In some cases useful info is found in syslog - try "dmesg | tail". rbd: map failed: (2) No such file or directory

原因

主要就是没有加载rbd模块，需要到所有的worker节点上加载rbd模块

解决

modprobe rbd

参考：https://forums.cnrancher.com/q_445.html

问题2：挂载失败

MountVolume.WaitForAttach failed for volume "pvc-aa0d2e46-3df3-4c70-a318-ad95d4d0810a" : rbd: map failed exit status 110, rbd output: rbd: sysfs write failed In some cases useful info is found in syslog - try "dmesg | tail". rbd: map failed: (110) Connection timed out

解决

ceph osd crush tunables hammer

参考：https://github.com/rancher/rancher/issues/13198#issuecomment-391920740

问题3：ceph HEALTH_WARN

HEALTH_WARN application not enabled on 1 pool(s)

解决

ceph health detail
ceph osd pool application enable kube-pool rbd

部署cephfs文件系统

k8s默认没有cephfs的provisioner，所以需要手动部署一个provisioner去对接cephfs

参考github链接：https://github.com/kubernetes-retired/external-storage/tree/master/ceph/cephfs

部署mds（元数据服务）

ceph-deploy mds create ceph-01

创建两个存储池，用来存放实际的数据以及元数据

ceph osd pool create cephfs_data 64
ceph osd pool create cephfs_metadata 64

创建cephfs文件系统

ceph fs new cephfs cephfs_metadata cephfs_data

查看mds状态

ceph mds stat
ceph -s

部署provisioner

这里有两种方式部署provisioner，其中一种是直接docker run的方式部署，另一种是通过deployment的方式部署到k8s中

docker run方式部署ceph-provisioner

docker run -tid -v /root/.kube:/kube -v /var/run/kubernetes:/var/run/kubernetes --privileged --net=host --name ceph-provisioner quay.io/external_storage/cephfs-provisioner   /usr/local/bin/cephfs-provisioner   -master=https://172.16.0.99:6443   -kubeconfig=/kube/config -id=cephfs-provisioner-1 -disable-ceph-namespace-isolation

deployment方式部署到k8s中

rbac相关yaml

kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: cephfs-provisioner
  namespace: cephfs
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: ["services"]
    resourceNames: ["kube-dns","coredns"]
    verbs: ["list", "get"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: cephfs-provisioner
subjects:
  - kind: ServiceAccount
    name: cephfs-provisioner
    namespace: cephfs
roleRef:
  kind: ClusterRole
  name: cephfs-provisioner
  apiGroup: rbac.authorization.k8s.io
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: cephfs-provisioner
  namespace: cephfs
rules:
  - apiGroups: [""]
    resources: ["secrets"]
    verbs: ["create", "get", "delete"]
  - apiGroups: [""]
    resources: ["endpoints"]
    verbs: ["get", "list", "watch", "create", "update", "patch"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: cephfs-provisioner
  namespace: cephfs
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: cephfs-provisioner
subjects:
- kind: ServiceAccount
  name: cephfs-provisioner
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: cephfs-provisioner
  namespace: cephfs

ceph-provisioner-deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: cephfs-provisioner
  namespace: cephfs
spec:
  replicas: 1
  selector:
    matchLabels:
      app: cephfs-provisioner
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: cephfs-provisioner
    spec:
      containers:
      - name: cephfs-provisioner
        image: "quay.io/external_storage/cephfs-provisioner:latest"
        env:
        - name: PROVISIONER_NAME
          value: ceph.com/cephfs
        - name: PROVISIONER_SECRET_NAMESPACE
          value: cephfs
        command:
        - "/usr/local/bin/cephfs-provisioner"
        args:
        - "-id=cephfs-provisioner-1"
        - "-disable-ceph-namespace-isolation"
      serviceAccount: cephfs-provisioner

保存上述两个文件，并执行kubectl apply

kubectl apply -f cephfs-provisioner-rbac.yaml
kubectl apply -f cephfs-provisioner-deployment.yaml

导入秘钥

ceph auth get-key client.admin > /tmp/secret
kubectl create ns cephfs
kubectl create secret generic ceph-secret-admin --from-file=/tmp/secret --namespace=cephfs

创建Storage class

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: cephfs
provisioner: ceph.com/cephfs
parameters:
    monitors: 172.16.31.11:6789
    adminId: admin
    adminSecretName: ceph-secret-admin
    adminSecretNamespace: "cephfs"
    claimRoot: /pvc-volumes

创建pvc

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: cephfs
spec:
  storageClassName: cephfs
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 1Gi

创建deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: test-cephfs
  name: test-cephfs
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: test-cephfs
  template:
    metadata:
      labels:
        app: test-cephfs
    spec:
      containers:
      - image: zerchin/network
        imagePullPolicy: IfNotPresent
        name: test-rbd
        volumeMounts:
        - mountPath: /data
          name: cephfs
      volumes:
      - name: cephfs
        persistentVolumeClaim:
          claimName: cephfs

常见问题

问题：无法挂载cephfs

	MountVolume.SetUp failed for volume "pvc-e4373999-8380-4211-99c5-5d096f234b35" : CephFS: mount failed: mount failed: exit status 5 Mounting command: mount Mounting arguments: -t ceph -o <masked>,<masked> 172.16.29.5:6789:/pvc-volumes/kubernetes/kubernetes-dynamic-pvc-b3e72054-4dc7-11eb-abdd-f21be6c36b31 /var/lib/kubelet/pods/5986dc99-b707-4ea9-b6b2-ae7ffd457c99/volumes/kubernetes.io~cephfs/pvc-e4373999-8380-4211-99c5-5d096f234b35 Output: modprobe: ERROR: ../libkmod/libkmod.c:586 kmod_search_moddep() could not open moddep file '/lib/modules/4.4.247-1.el7.elrepo.x86_64/modules.dep.bin' modprobe: FATAL: Module ceph not found in directory /lib/modules/4.4.247-1.el7.elrepo.x86_64 failed to load ceph kernel module (1) mount error 5 = Input/output error

此时手动在后台使用mount.ceph挂载对应的目录也挂载不上

原因

在 cephfs_provisoner.py 的实现中，默认添加了对 cephfs namespace 的支持，因此在对 volume 授权时会添加对 namespace 相关的权限设置。因为，我们使用的 ceph 版本 luminous 没有对 namespace 进行支持，所以，在使用时产生了创建的 volume 挂载到 pod 内后没有读写权限"input/output error"的问题。 此时，你在 cephfs 端查看卷的读写权限时，你可以看到目录读写权限都是问号。于是我们修改了这部分逻辑，去掉了 namespace 相关的部分。

解决

设置ceph-provisioner启动时添加该参数-disable-ceph-namespace-isolation

参考：https://www.infoq.cn/article/jqhjzvvl11escvfydruc

扩展

高可用

添加多个mon

ceph-deploy mon add ceph-02 ceph-03

当ceph集群有多个mon时，ceph会同步mon并形成仲裁，检查仲裁状态命令如下：

ceph quorum_status --format json-pretty

添加mgr

ceph-deploy mgr create ceph-02 ceph-03

查看集群状态

ceph -s

节点清理ceph

ceph-deploy purge [ceph-node]
ceph-deploy purgedata [ceph-node]
ceph-deploy forgetkeys
rm ceph.*