Ceph 14.2.5-K8S 使用Ceph存储实战 -- <6>

K8S 使用Ceph存储

PV、PVC概述

管理存储是管理计算的一个明显问题。PersistentVolume子系统为用户和管理员提供了一个API，用于抽象如何根据消费方式提供存储的详细信息。于是引入了两个新的API资源：PersistentVolume和PersistentVolumeClaim

PersistentVolume（PV）是集群中已由管理员配置的一段网络存储。 集群中的资源就像一个节点是一个集群资源。 PV是诸如卷之类的卷插件，但是具有独立于使用PV的任何单个pod的生命周期。 该API对象包含存储的实现细节，即NFS，iSCSI或云提供商特定的存储系统。

PersistentVolumeClaim（PVC）是用户存储的请求。 它类似于pod。Pod消耗节点资源，PVC消耗存储资源。 pod可以请求特定级别的资源（CPU和内存）。 权限要求可以请求特定的大小和访问模式。

虽然PersistentVolumeClaims允许用户使用抽象存储资源，但是常见的是，用户需要具有不同属性（如性能）的PersistentVolumes，用于不同的问题。 管理员需要能够提供多种不同于PersistentVolumes，而不仅仅是大小和访问模式，而不会使用户了解这些卷的实现细节。 对于这些需求，存在StorageClass资源。

StorageClass为集群提供了一种描述他们提供的存储的“类”的方法。 不同的类可能映射到服务质量级别，或备份策略，或者由群集管理员确定的任意策略。 Kubernetes本身对于什么类别代表是不言而喻的。 这个概念有时在其他存储系统中称为“配置文件”

POD动态供给

动态供给主要是能够自动帮你创建pv，需要多大的空间就创建多大的pv。k8s帮助创建pv，创建pvc就直接api调用存储类来寻找pv。

如果是存储静态供给的话，会需要我们手动去创建pv，如果没有足够的资源，找不到合适的pv，那么pod就会处于pending等待的状态。而动态供给主要的一个实现就是StorageClass存储对象，其实它就是声明你使用哪个存储，然后帮你去连接，再帮你去自动创建pv。

POD使用RBD做为持久数据卷

安装与配置

RBD支持ReadWriteOnce，ReadOnlyMany两种模式
1、配置rbd-provisioner

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: apps/v1
kind: Deployment
metadata:
  name: rbd-provisioner
  namespace: kube-system
spec:
  selector:
    matchLabels:
      app: rbd-provisioner
  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

2、配置storageclass

1、创建pod时，kubelet需要使用rbd命令去检测和挂载pv对应的ceph image，所以要在所有的worker节点安装ceph客户端ceph-common。
将ceph的ceph.client.admin.keyring和ceph.conf文件拷贝到master的/etc/ceph目录下
yum -y install ceph-common

2、创建 osd pool 在ceph的mon或者admin节点
ceph osd pool create kube 128 128 
ceph osd pool ls

3、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

4、查看key 在ceph的mon或者admin节点
ceph auth get-key client.admin
AQCrBwteAI7TOhAAzFgRZO0MK/da2AFn5EddqA==
ceph auth get-key client.kube
AQDlPwxeT1MfBhAAB66MV550XcNcVfMq9dsnZQ==

5、创建 admin secret
kubectl create secret generic ceph-secret --type="kubernetes.io/rbd" 
--from-literal=key=AQCrBwteAI7TOhAAzFgRZO0MK/da2AFn5EddqA== 
--namespace=kube-system

6、在 default 命名空间创建pvc用于访问ceph的 secret
kubectl create secret generic ceph-user-secret --type="kubernetes.io/rbd" 
--from-literal=key=AQDlPwxeT1MfBhAAB66MV550XcNcVfMq9dsnZQ== 
--namespace=default

3、配置StorageClass

cat >storageclass-ceph-rdb.yaml<<EOF
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: dynamic-ceph-rdb
provisioner: ceph.com/rbd
parameters:
  monitors: 192.168.25.224:6789,192.168.25.227:6789,192.168.25.228:6789
  adminId: admin
  adminSecretName: ceph-secret
  adminSecretNamespace: kube-system
  pool: kube
  userId: kube
  userSecretName: ceph-user-secret
  fsType: ext4
  imageFormat: "2"
  imageFeatures: "layering"
EOF

4、创建yaml

kubectl apply -f storageclass-ceph-rdb.yaml

5、查看sc

kubectl get storageclasses

测试使用

1、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

2、查看

kubectl get pvc
kubectl get pv

3、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

4、查看

kubectl get pods -o wide

查看rbd-provisioner-pod 日志

E0101 09:29:53.509202       1 provision.go:232] dns lookup of "192.168.25.224" failed: err read udp 10.243.169.134:57984->10.0.0.2:53: i/o timeout
E0101 09:29:55.509858       1 provision.go:232] dns lookup of "192.168.25.227" failed: err read udp 10.243.169.134:38583->10.0.0.2:53: i/o timeout
I0101 09:29:57.252279       1 provision.go:132] successfully created rbd image "kubernetes-dynamic-pvc-4568768d-2c79-11ea-b8d3-367aebbc365a"
I0101 09:29:57.252307       1 controller.go:1043] volume "pvc-aa54a7a6-599b-4057-b9d3-eedc148c2604" for claim "default/ceph-rdb-claim" created
  101 09:29:57.260381       1 controller.go:1060] volume "pvc-aa54a7a6-599b-4057-b9d3-eed▽148c2604" for claim "default/ceph-rdb-claim" saved
I0101 09:29:57.260408       1 controller.go:1096] volume "pvc-aa54a7a6-599b-4057-b9d3-eedc148c2604" provisioned for claim "default/ceph-rdb-claim"
I0101 09:29:57.260793       1 event.go:221] Event(v1.ObjectReference{Kind:"PersistentVolumeClaim", Namespace:"default", Name:"ceph-rdb-claim", UID:"aa54a7a6-599b-4057-b9d3-eedc148c2604", APIVersion:"v1", ResourceVersion:"2729557", FieldPath:""}): type: 'Normal' reason: 'ProvisioningSucceeded' Successfully provisioned volume pvc-aa54a7a6-599b-4057-b9d3-eedc148c2604

5、修改文件内容

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

6、访问测试

curl http://$podip

7、清理

kubectl delete -f nginx-pod.yaml
kubectl delete -f ceph-rdb-pvc-test.yaml

POD使用CephFS做为持久数据卷

CephFS方式支持k8s的pv的3种访问模式ReadWriteOnce，ReadOnlyMany ，ReadWriteMany

Ceph端创建CephFS pool

1、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

2、创建一个CephFS

ceph fs new cephfs fs_metadata fs_data

3、查看

ceph fs ls

部署 cephfs-provisioner

1、使用社区提供的cephfs-provisioner

cat >external-storage-cephfs-provisioner.yaml<<EOF
apiVersion: v1
kind: Secret
metadata:
  name: ceph-secret-admin 
  namespace: kube-system
type: "kubernetes.io/rbd"
data:
  # ceph auth get-key client.admin | base64
  key: QVFDckJ3dGVBSTdUT2hBQXpGZ1JaTzBNSy9kYTJBRm41RWRkcUE9PQ== 
[root@k8s-master1 cephfs]# cat cephfs-provisioner-deployment.yaml 
apiVersion: apps/v1 
kind: Deployment
metadata:
  name: cephfs-provisioner
  namespace: kube-system
spec:
  selector: 
    matchLabels:
      app: cephfs-provisioner
  replicas: 1
  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: kube-system
        command:
        - "/usr/local/bin/cephfs-provisioner"
        args:
        - "-id=cephfs-provisioner-1"
        - "-disable-ceph-namespace-isolation=true"
      serviceAccount: cephfs-provisioner
[root@k8s-master1 cephfs]# 
[root@k8s-master1 cephfs]# ls 
cephfs-provisioner-deployment.yaml  pvc.yaml      serviceaccount-rbac.yaml
nginx-pod.yaml                      secrets.yaml  storageclass.yaml
[root@k8s-master1 cephfs]# cat serviceaccount-rbac.yaml 
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: cephfs-provisioner
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: cephfs-provisioner
  namespace: kube-system
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: kube-system
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: cephfs-provisioner
subjects:
- kind: ServiceAccount
  name: cephfs-provisioner
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: cephfs-provisioner
  namespace: kube-system
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"]
  - apiGroups: [""]
    resources: ["secrets"]
    verbs: ["get", "create", "delete"]
  - apiGroups: ["policy"]
    resourceNames: ["cephfs-provisioner"]
    resources: ["podsecuritypolicies"]
    verbs: ["use"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
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: apps/v1 
kind: Deployment
metadata:
  name: cephfs-provisioner
  namespace: kube-system
spec:
  selector: 
    matchLabels:
      app: cephfs-provisioner
  replicas: 1
  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: kube-system
        command:
        - "/usr/local/bin/cephfs-provisioner"
        args:
        - "-id=cephfs-provisioner-1"
        - "-disable-ceph-namespace-isolation=true"
      serviceAccount: cephfs-provisioner
EOF
kubectl apply -f external-storage-cephfs-provisioner.yaml

2、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

1、查看key 在ceph的mon或者admin节点

ceph auth get-key client.admin

2、创建 admin secret

apiVersion: v1
kind: Secret
metadata:
  name: ceph-secret-admin 
  namespace: kube-system
type: "kubernetes.io/rbd"
data:
  # ceph auth get-key client.admin | base64
  key: QVFDckJ3dGVBSTdUT2hBQXpGZ1JaTzBNSy9kYTJBRm41RWRkcUE9PQ== 

3、查看 secret

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

4、配置 StorageClass

cat >storageclass-cephfs.yaml<<EOF
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: cephfs
provisioner: ceph.com/cephfs
reclaimPolicy: Retain #回收策略
parameters:
    monitors: 192.168.25.224,192.168.25.227,192.168.25.228:6789 # ceph mon 集群地址
    adminId: admin
    adminSecretName: ceph-secret-admin
    adminSecretNamespace: "kube-system"
    claimRoot: /pvc-volumes
EOF

5、创建

kubectl apply -f storageclass-cephfs.yaml

6、查看

kubectl get sc

测试使用

1、创建pvc测试

cat >cephfs-pvc-test.yaml<<EOF
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: cephfs-claim1
spec:
  storageClassName: cephfs
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 2Gi
EOF
kubectl apply -f cephfs-pvc-test.yaml

2、查看

kubectl get pvc
kubectl get pv

3、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: cephfs-claim1 
EOF
kubectl apply -f nginx-pod.yaml

4、查看

kubectl get pods -o wide

5、修改文件内容

kubectl exec -ti nginx-pod2 -- /bin/sh -c 'echo This is from CephFS!!! > /usr/share/nginx/html/index.html'

6、访问pod测试

curl http://$podip

7、清理

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

故障解决：

参考1：https://blog.51cto.com/ygqygq2/2163656

参考2：https://blog.51cto.com/juestnow/2408267 (推荐)