k8s部署zk集群

Posted 2020-12-14

一、简介

1.1、statefulset控制器简介

statefulset控制器是有状态应用副本集；在k8s集群statefulset用于管理以下副本集：

• 稳定且唯一的网络标识符
• 稳定且持久的存储
• 有序，平滑的部署和扩展
• 有序，平滑的删除和终止
• 有序的滚动更新
  statefulset包含三个组件：headless service、StatefulSet，volumeClaimTemplate
• headless service：确保解析名称直达后端pod
• volumeClaimTemplate：卷申请模板，每创建一个pod时，自动申请一个pvc，从而请求绑定pv
• StatefulSet：控制器

二、部署

2.1、创建pv与pvc

kubernetes上的存储卷类型
emptyDir：空目录，按需创建；删除pod后存储卷中的数据也被删除，一般用于临时目录或缓存
hostPath：主机路径，在node上找一个目录与pod中的容器建立联系
gitRepo：基于emptyDir实现的git仓库 clone到emptyDir存储卷
NFS：将现有NFS（网络文件系统）共享安装到Pod中

2.1.1、准备

master节点：

kubectl create ns bigdata

node节点：

mkdir -pv /data/pv/zk{1..3}

2.1.2、定义pv与pvc资源文件

实验环境为虚拟机环境，因此使用的存储卷类型为hostPath。

apiVersion: v1
kind: PersistentVolume
metadata: 
  name: k8s-pv-zk1
  namespace: bigdata
  labels: 
    type: local
spec: 
  capacity: 
    storage: 2Gi
  accessModes: 
    - ReadWriteOnce
  hostPath: 
    path: /data/pv/zk1
  persistentVolumeReclaimPolicy: Recycle
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: k8s-pv-zk2
  namespace: bigdata
  labels:
    type: local
spec:
  capacity:
    storage: 2Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: /data/pv/zk2
  persistentVolumeReclaimPolicy: Recycle
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: k8s-pv-zk3
  namespace: bigdata
  labels:
    type: local
spec:
  capacity:
    storage: 2Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: /data/pv/zk3
  persistentVolumeReclaimPolicy: Recycle

2.1.3、创建pv与pvc

kubectl??apply? -f??zookeeper-pv.yaml

2.1.4、查看pv

[root@master ~]# kubectl get pv 
NAME         CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   REASON   AGE
k8s-pv-zk1   2Gi        RWO            Recycle          Available                                   6m42s
k8s-pv-zk2   2Gi        RWO            Recycle          Available                                   6m42s
k8s-pv-zk3   2Gi        RWO            Recycle          Available                                   6m42s

2.2、zk集群部署

2.2.1、官方资源清单修改

官方资源清单：https://kubernetes.io/zh/docs/tutorials/stateful-application/zookeeper/

apiVersion: v1
kind: Service
metadata:
  name: zk-hs
  namespace: bigdata
  labels:
    app: zk
spec:
  ports:
  - port: 2888
    name: server
  - port: 3888
    name: leader-election
  clusterIP: None
  selector:
    app: zk
---
apiVersion: v1
kind: Service
metadata:
  name: zk-cs
  namespace: bigdata
  labels:
    app: zk
spec:
  ports:
  - port: 2181
    name: client
  selector:
    app: zk
---
apiVersion: policy/v1beta1
kind: PodDisruptionBudget
metadata:
  name: zk-pdb
  namespace: bigdata
spec:
  selector:
    matchLabels:
      app: zk
  maxUnavailable: 1
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: zk
  namespace: bigdata
spec:
  selector:
    matchLabels:
      app: zk
  serviceName: zk-hs
  replicas: 3
  updateStrategy:
    type: RollingUpdate
  podManagementPolicy: OrderedReady
  template:
    metadata:
      labels:
        app: zk
    spec:
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                matchExpressions:
                  - key: "app"
                    operator: In
                    values:
                    - zk
              topologyKey: "kubernetes.io/hostname"
      containers:
      - name: kubernetes-zookeeper
        imagePullPolicy: IfNotPresent
        image: "mirrorgcrio/kubernetes-zookeeper:1.0-3.4.10"
        resources:
          requests:
            memory: "500Mi"
            cpu: "0.5"
        ports:
        - containerPort: 2181
          name: client
        - containerPort: 2888
          name: server
        - containerPort: 3888
          name: leader-election
        command:
        - sh
        - -c
        - "start-zookeeper           --servers=3           --data_dir=/var/lib/zookeeper/data           --data_log_dir=/var/lib/zookeeper/data/log           --conf_dir=/opt/zookeeper/conf           --client_port=2181           --election_port=3888           --server_port=2888           --tick_time=2000           --init_limit=10           --sync_limit=5           --heap=512M           --max_client_cnxns=60           --snap_retain_count=3           --purge_interval=12           --max_session_timeout=40000           --min_session_timeout=4000           --log_level=INFO"
        readinessProbe:
          exec:
            command:
            - sh
            - -c
            - "zookeeper-ready 2181"
          initialDelaySeconds: 10
          timeoutSeconds: 5
        livenessProbe:
          exec:
            command:
            - sh
            - -c
            - "zookeeper-ready 2181"
          initialDelaySeconds: 10
          timeoutSeconds: 5
        volumeMounts:
        - name: datadir
          mountPath: /var/lib/zookeeper
  volumeClaimTemplates:
  - metadata:
      name: datadir
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 2Gi

2.2.2、创建zk集群

kubectl  apply  -f  zookeeper.yaml

2.2.3、查看pod

[root@master ~]# kubectl get pods -n bigdata -o wide
NAME   READY   STATUS    RESTARTS   AGE    IP               NODE    NOMINATED NODE   READINESS GATES
zk-0   1/1     Running   0          109s   10.122.104.4     node2   <none>           <none>
zk-1   1/1     Running   0          95s    10.122.166.134   node1   <none>           <none>
zk-2   1/1     Running   0          78s    10.122.135.1     node3   <none>           <none>

2.2.4、查看pvc

[root@master ~]# kubectl get pvc -n bigdata -o wide
NAME           STATUS   VOLUME       CAPACITY   ACCESS MODES   STORAGECLASS   AGE    VOLUMEMODE
datadir-zk-0   Bound    k8s-pv-zk1   2Gi        RWO                           19m    Filesystem
datadir-zk-1   Bound    k8s-pv-zk3   2Gi        RWO                           115s   Filesystem
datadir-zk-2   Bound    k8s-pv-zk2   2Gi        RWO                           98s    Filesystem

2.2.5、查看zk配置

[root@master ~]# kubectl exec -n bigdata zk-0 -- cat /opt/zookeeper/conf/zoo.cfg
#This file was autogenerated DO NOT EDIT
clientPort=2181
dataDir=/var/lib/zookeeper/data
dataLogDir=/var/lib/zookeeper/data/log
tickTime=2000
initLimit=10
syncLimit=5
maxClientCnxns=60
minSessionTimeout=4000
maxSessionTimeout=40000
autopurge.snapRetainCount=3
autopurge.purgeInteval=12
server.1=zk-0.zk-hs.bigdata.svc.cluster.local:2888:3888
server.2=zk-1.zk-hs.bigdata.svc.cluster.local:2888:3888
server.3=zk-2.zk-hs.bigdata.svc.cluster.local:2888:3888

2.2.6、查看集群状态

[root@master ~]# kubectl exec -n bigdata zk-0 zkServer.sh status
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl kubectl exec [POD] -- [C
OMMAND] instead.ZooKeeper JMX enabled by default
Using config: /usr/bin/../etc/zookeeper/zoo.cfg
Mode: follower
[root@master ~]# kubectl exec -n bigdata zk-1 zkServer.sh status
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl kubectl exec [POD] -- [C
OMMAND] instead.ZooKeeper JMX enabled by default
Using config: /usr/bin/../etc/zookeeper/zoo.cfg
Mode: leader
[root@master ~]# kubectl exec -n bigdata zk-2 zkServer.sh status
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl kubectl exec [POD] -- [C
OMMAND] instead.ZooKeeper JMX enabled by default
Using config: /usr/bin/../etc/zookeeper/zoo.cfg
Mode: follower

参考文章：
官方zk实例：https://kubernetes.io/zh/docs/tutorials/stateful-application/zookeeper/
资源清单相关：https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.18/#statefulset-v1-apps