使用 K8S 部署 zookeeper 集群

一. zookeeper原理

zookeeper 分布式服务框架是Apache Hadoop 的一个子项目，它主要是用来解决分布式应用中经常遇到的一些数据管理问题，如：统一命名服务、状态同步服务、集群管理、分布式应用配置项的管理等。简单的说，zookeeper=文件系统+通知机制。

zookeeper是一个高性能、开源的分布式应用协调服务，它提供了简单原始的功能，分布式应用可以基于它实现更高级的服务，比如实现同步(分布式锁)、配置管理、集群管理。它被设计为易于编程，使用文件系统目录树作为数据模型。服务端使用Java语言编写，并且提供了Java和C语言的客户端。

二、部署

zookeeper-pvc.yaml

apiVersion: v1
kind: PersistentVolume
metadata:
  name: k8s-pv-zk01
  namespace: test
  labels:
    app: zk
  annotations:
    volume.beta.kubernetes.io/storage-class: "anything"
spec:
  capacity:
    storage: 1Gi
  accessModes:
  - ReadWriteOnce
  hostPath:
    path: /data/k8snfs/zookeeper/zk01
  persistentVolumeReclaimPolicy: Recycle
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: k8s-pv-zk02
  namespace: test
  labels:
    app: zk
  annotations:
    volume.beta.kubernetes.io/storage-class: "anything"
spec:
  capacity:
    storage: 1Gi
  accessModes:
  - ReadWriteOnce
  hostPath:
    path: /data/k8snfs/zookeeper/zk02
  persistentVolumeReclaimPolicy: Recycle
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: k8s-pv-zk03
  namespace: test
  labels:
    app: zk
  annotations:
    volume.beta.kubernetes.io/storage-class: "anything"
spec:
  capacity:
    storage: 1Gi
  accessModes:
  - ReadWriteOnce
  hostPath:
    path: /data/k8snfs/zookeeper/zk03
  persistentVolumeReclaimPolicy: Recycle
---

zookeeper.yaml

apiVersion: v1
kind: Service
metadata:
  name: zk-hs
  namespace: test
  labels:
    app: zk
spec:
  selector:
    app: zk
  clusterIP: None
  ports:
  - name: server
    port: 2888
  - name: leader-election
    port: 3888
--- 
apiVersion: v1
kind: Service
metadata:
  name: zk-cs
  namespace: test
  labels:
    app: zk
spec:
  selector:
    app: zk
  type: NodePort
  ports:
  - name: client
    port: 2181
    nodePort: 31812
---
apiVersion: policy/v1beta1
kind: PodDisruptionBudget
metadata:
  name: zk-pdb
  namespace: test
spec:
  selector:
    matchLabels:
      app: zk
  maxUnavailable: 1
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: zk
  namespace: test
spec:
  selector:
    matchLabels:
      app: zk # has to match .spec.template.metadata.labels
  serviceName: "zk-hs"
  replicas: 3 # by default is 1
  updateStrategy:
    type: RollingUpdate
  podManagementPolicy: Parallel
  template:
    metadata:
      labels:
        app: zk # has to match .spec.selector.matchLabels
    spec:
      containers:
      - name: zk
        imagePullPolicy: Always
        image: guglecontainers/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"
        volumeMounts:
        - name: datadir
          mountPath: /var/lib/zookeeper
  volumeClaimTemplates:
  - metadata:
      name: datadir
      namespace: test
      annotations:
        volume.beta.kubernetes.io/storage-class: "anything"
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 1Gi

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