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K8s - 安装部署Kafka、ZooKeeper集群教程（支持从K8s外部访问）

作者：hangge | 2021-06-16 15:33
    本文演示如何在 K8s下部署 Kafka 集群，并且搭建后除了可以从 K8s 内部访问 Kafka 服务，也支持从 K8s 集群外部访问 Kafka 服务。服务的集群部署通常有两种方式：一种是 StatefulSet，另一种是 Service&Deployment。本次我们使用 StatefulSet 方式搭建 ZooKeeper 集群，使用 Service&Deployment 搭建 Kafka 集群。

一、创建 NFS 存储

    NFS 存储主要是为了给 Kafka、ZooKeeper 提供稳定的后端存储，当 Kafka、ZooKeeper 的 Pod 发生故障重启或迁移后，依然能获得原先的数据。


1，安装 NFS

这里我选择在 master 节点创建 NFS 存储，首先执行如下命令安装 NFS：
yum -y install nfs-utils
yum -y install rpcbind

2，创建共享文件夹

（1）执行如下命令创建 6 个文件夹：
mkdir -p /usr/local/k8s/zookeeper/pv{1..3}
mkdir -p /usr/local/k8s/kafka/pv{1..3}

（2）编辑 /etc/exports 文件： 
vi /etc/exports

（3）在里面添加如下内容： 
/usr/local/k8s/kafka/pv1 *(rw,sync,no_root_squash)
/usr/local/k8s/kafka/pv2 *(rw,sync,no_root_squash)
/usr/local/k8s/kafka/pv3 *(rw,sync,no_root_squash)
/usr/local/k8s/zookeeper/pv1 *(rw,sync,no_root_squash)
/usr/local/k8s/zookeeper/pv2 *(rw,sync,no_root_squash)
/usr/local/k8s/zookeeper/pv3 *(rw,sync,no_root_squash)

（4）保存退出后执行如下命令重启服务：
如果执行 systemctl restart nfs 报“Failed to restart nfs.service: Unit nfs.service not found.”错误，可以尝试改用如下命令：
  • sudo service nfs-server start 
systemctl restart rpcbind
systemctl restart nfs
systemctl enable nfs

（5）执行 exportfs -v 命令可以显示出所有的共享目录：

（6）而其他的 Node 节点上需要执行如下命令安装 nfs-utils 客户端：
yum -y install nfs-util

（7）然后其他的 Node 节点上可执行如下命令（ip 为 Master 节点 IP）查看 Master 节点上共享的文件夹： 
showmount -e 170.106.37.33

二、创建 ZooKeeper 集群

1，创建 ZooKeeper PV

（1）首先创建一个 zookeeper-pv.yaml 文件，内容如下：
注意：170.106.37.33 需要改成实际 NFS 服务器地址：
apiVersion: v1
kind: PersistentVolume
metadata:
  name: k8s-pv-zk01
  labels:
    app: zk
  annotations:
    volume.beta.kubernetes.io/storage-class: "anything"
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    server: 170.106.37.33
    path: "/usr/local/k8s/zookeeper/pv1"
  persistentVolumeReclaimPolicy: Recycle
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: k8s-pv-zk02
  labels:
    app: zk
  annotations:
    volume.beta.kubernetes.io/storage-class: "anything"
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    server: 170.106.37.33
    path: "/usr/local/k8s/zookeeper/pv2"
  persistentVolumeReclaimPolicy: Recycle
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: k8s-pv-zk03
  labels:
    app: zk
  annotations:
    volume.beta.kubernetes.io/storage-class: "anything"
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    server: 170.106.37.33
    path: "/usr/local/k8s/zookeeper/pv3"
  persistentVolumeReclaimPolicy: Recycle

（2）然后执行如下命令创建 PV： 
kubectl apply -f zookeeper-pv.yaml

（3）执行如下命令可以查看是否创建成功： 
kubectl get pv

2，创建 ZooKeeper 集群

（1）我们这里要搭建一个包含 3 个节点的 ZooKeeper 集群。首先创建一个 zookeeper.yaml 文件，内容如下：
apiVersion: v1
kind: Service
metadata:
  name: zk-hs
  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
  labels:
    app: zk
spec:
  selector:
    app: zk
  type: NodePort
  ports:
    - name: client
      port: 2181
      nodePort: 31811
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: zk
spec:
  serviceName: "zk-hs"
  replicas: 3 # by default is 1
  selector:
    matchLabels:
      app: zk # has to match .spec.template.metadata.labels
  updateStrategy:
    type: RollingUpdate
  podManagementPolicy: Parallel
  template:
    metadata:
      labels:
        app: zk # has to match .spec.selector.matchLabels
    spec:
      containers:
        - name: zk
          imagePullPolicy: Always
          image: leolee32/kubernetes-library:kubernetes-zookeeper1.0-3.4.10
          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=4G \
        --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
        annotations:
          volume.beta.kubernetes.io/storage-class: "anything"
      spec:
        accessModes: [ "ReadWriteOnce" ]
        resources:
          requests:
            storage: 1Gi

（2）然后执行如下命令开始创建： 
kubectl apply -f zookeeper.yaml

（3）执行如下命令可以查看是否创建成功： 
kubectl get pods
kubectl get service

三、创建 Kafka 集群

（1）我们这里要搭建一个包含 3 个节点的 Kafka 集群。首先创建一个 kafka.yaml 文件，内容如下：
注意：
  • nfs 地址需要改成实际 NFS 服务器地址。
  • status.hostIP 表示宿主机的 IP，即 Pod 实际最终部署的 Node 节点 IP（本文我是直接部署到 Master 节点上），将 KAFKA_ADVERTISED_HOST_NAME 设置为宿主机 IP 可以确保 K8s 集群外部也可以访问 Kafka。
apiVersion: v1
kind: Service
metadata:
  name: kafka-service-1
  labels:
    app: kafka-service-1
spec:
  type: NodePort
  ports:
    - port: 9092
      name: kafka-service-1
      targetPort: 9092
      nodePort: 30901
      protocol: TCP
  selector:
    app: kafka-1
---
apiVersion: v1
kind: Service
metadata:
  name: kafka-service-2
  labels:
    app: kafka-service-2
spec:
  type: NodePort
  ports:
    - port: 9092
      name: kafka-service-2
      targetPort: 9092
      nodePort: 30902
      protocol: TCP
  selector:
    app: kafka-2
---
apiVersion: v1
kind: Service
metadata:
  name: kafka-service-3
  labels:
    app: kafka-service-3
spec:
  type: NodePort
  ports:
    - port: 9092
      name: kafka-service-3
      targetPort: 9092
      nodePort: 30903
      protocol: TCP
  selector:
    app: kafka-3
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: kafka-deployment-1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: kafka-1
  template:
    metadata:
      labels:
        app: kafka-1
    spec:
      containers:
        - name: kafka-1
          image: wurstmeister/kafka
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 9092
          env:
            - name: KAFKA_ZOOKEEPER_CONNECT
              value: zk-0.zk-hs.default.svc.cluster.local:2181,zk-1.zk-hs.default.svc.cluster.local:2181,zk-2.zk-hs.default.svc.cluster.local:2181
            - name: KAFKA_BROKER_ID
              value: "1"
            - name: KAFKA_CREATE_TOPICS
              value: mytopic:2:1
            - name: KAFKA_LISTENERS
              value: PLAINTEXT://0.0.0.0:9092
            - name: KAFKA_ADVERTISED_PORT
              value: "30901"
            - name: KAFKA_ADVERTISED_HOST_NAME
              valueFrom:
                fieldRef:
                  fieldPath: status.hostIP
          volumeMounts:
            - name: datadir
              mountPath: /var/lib/kafka
      volumes:
        - name: datadir
          nfs:
            server: 170.106.37.33
            path: "/usr/local/k8s/kafka/pv1"
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: kafka-deployment-2
spec:
  replicas: 1
  selector:
    matchLabels:
      app: kafka-2
  template:
    metadata:
      labels:
        app: kafka-2
    spec:
      containers:
        - name: kafka-2
          image: wurstmeister/kafka
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 9092
          env:
            - name: KAFKA_ZOOKEEPER_CONNECT
              value: zk-0.zk-hs.default.svc.cluster.local:2181,zk-1.zk-hs.default.svc.cluster.local:2181,zk-2.zk-hs.default.svc.cluster.local:2181
            - name: KAFKA_BROKER_ID
              value: "2"
            - name: KAFKA_LISTENERS
              value: PLAINTEXT://0.0.0.0:9092
            - name: KAFKA_ADVERTISED_PORT
              value: "30902"
            - name: KAFKA_ADVERTISED_HOST_NAME
              valueFrom:
                fieldRef:
                  fieldPath: status.hostIP
          volumeMounts:
            - name: datadir
              mountPath: /var/lib/kafka
      volumes:
        - name: datadir
          nfs:
            server: 170.106.37.33
            path: "/usr/local/k8s/kafka/pv2"
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: kafka-deployment-3
spec:
  replicas: 1
  selector:
    matchLabels:
      app: kafka-3
  template:
    metadata:
      labels:
        app: kafka-3
    spec:
      containers:
        - name: kafka-3
          image: wurstmeister/kafka
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 9092
          env:
            - name: KAFKA_ZOOKEEPER_CONNECT
              value: zk-0.zk-hs.default.svc.cluster.local:2181,zk-1.zk-hs.default.svc.cluster.local:2181,zk-2.zk-hs.default.svc.cluster.local:2181
            - name: KAFKA_BROKER_ID
              value: "3"
            - name: KAFKA_LISTENERS
              value: PLAINTEXT://0.0.0.0:9092
            - name: KAFKA_ADVERTISED_PORT
              value: "30903"
            - name: KAFKA_ADVERTISED_HOST_NAME
              valueFrom:
                fieldRef:
                  fieldPath: status.hostIP
          volumeMounts:
            - name: datadir
              mountPath: /var/lib/kafka
      volumes:
        - name: datadir
          nfs:
            server: 170.106.37.33
            path: "/usr/local/k8s/kafka/pv3"

（2）然后执行如下命令开始创建： 
kubectl apply -f kafka.yaml

（3）执行如下命令可以查看是否创建成功： 
kubectl get pods
kubectl get service

四、开始测试

1，K8s 集群内部测试

（1）首先执行如下命令进入一个容器：
kubectl exec -it kafka-deployment-1-59f87c7cbb-99k46 /bin/bash

（2）接着执行如下命令创建一个名为 test_topic 的 topic： 
kafka-topics.sh --create --topic test_topic --zookeeper zk-0.zk-hs.default.svc.cluster.local:2181,zk-1.zk-hs.default.svc.cluster.local:2181,zk-2.zk-hs.default.svc.cluster.local:2181 --partitions 1 --replication-factor 1

（3）创建后执行如下命令开启一个生产者，启动后可以直接在控制台中输入消息来发送，控制台中的每一行数据都会被视为一条消息来发送。 
kafka-console-producer.sh --broker-list kafka-service-1:9092,kafka-service-2:9092,kafka-service-3:9092 --topic test_topic

（4）重新再打开一个终端连接服务器，然后进入容器后执行如下命令开启一个消费者： 
kafka-console-consumer.sh --bootstrap-server kafka-service-1:9092,kafka-service-2:9092,kafka-service-3:9092 --topic test_topic

（5）再次打开之前的消息生产客户端来发送消息，并观察消费者这边对消息的输出来体验 Kafka 对消息的基础处理。

2，集群外出测试

    使用 Kafka 客户端工具（Offset Explorer）连接 Kafka 集群（可以通过 zookeeper 地址连接，也可以通过 kafka 地址连接），可以连接成功并能查看到数据。
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