Kubernetes服务部署 —— Kafka

1、简介

Kafka和zookeeper是两种典型的有状态的应用集群服务。首先kafka和zookeeper都需要存储盘来保存有状态信息；其次kafka和zookeeper每一个实例都需要有对应的实例Id (Kafka需broker.id, zookeeper需要my.id) 来作为集群内部每个成员的标识，集群内节点之间进行内部通信时需要用到这些标识。

对于这类服务的部署，需要解决两个大的问题：一个是状态保存，另一个是集群管理 (多服务实例管理)。kubernetes中提的StatefulSet方便了有状态集群服务在上的部署和管理。通常来说，通过下面三个手段来实现有状态集群服务的部署：

• 通过Init Container来做集群的初始化工 作。

• 通过Headless Service来维持集群成员的稳定关系。

• 通过Persistent Volume和Persistent Volume Claim提供网络存储来持久化数据。

因此，在K8S集群里面部署类似kafka、zookeeper这种有状态的服务，不能使用Deployment，必须使用StatefulSet来部署，有状态简单来说就是需要持久化数据，比如日志、数据库数据、服务状态等。

2、应用场景

• 稳定的持久化存储，即Pod重新调度后还是能访问到相同的持久化数据，基于PVC来实现。

• 稳定的网络标志，即Pod重新调度后其PodName和HostName不变，基于Headless Service（即没有Cluster IP的Service）来实现。

• 有序部署，有序扩展，即Pod是有顺序的，在部署或者扩展的时候要依据定义的顺序依次依次进行（即从0到N-1，在下一个Pod运行之前所有之前的Pod必须都是Running和Ready状态），基于init containers来实现。

• 有序收缩，有序删除（即从N-1到0）。

3、格式说明

statefulSetName-{0…N-1}.serviceName.namespace.svc.cluster.local，其中：

• statefulSetName为StatefulSet的名字。

• 0…N-1为Pod所在的序号，从0开始到N-1。

• serviceName为Headless Service的名字。

• namespace为服务所在的namespace，Headless Servic和StatefulSet必须在相同的namespace。

• svc.cluster.local为K8S的Cluster Domain集群根域。

4、创建namespace

root@ldap:/opt/k8s-server/kafka/kafka-test/test# Kubectl create ns boss

5、部署zookeeper集群

创建svc

root@ldap:/opt/k8s-server/kafka/kafka-test/test# cat zk-service.yaml 

apiVersion: v1
kind: Service
metadata:
  name: zk-hs
  namespace: boss
  labels:
    app: zk
spec:
  ports:
    - port: 2888
      name: server
    - port: 3888
      name: leader-election
  clusterIP: None  # 使用 clusterIP 的方式，适用于 headless 服务
  selector:
    app: zk
---
apiVersion: v1
kind: Service
metadata:
  name: zk-cs
  namespace: boss
  labels:
    app: zk
spec:
  ports:
    - port: 2181
      name: client
  selector:
    app: zk

允许最多1个不可用

apiVersion: policy/v1
kind: PodDisruptionBudget
metadata:
  name: zk-pdb
  namespace: zookeeper
spec:
  selector:
    matchLabels:
      app: zk
  maxUnavailable: 1

部署zookeeper

root@ldap:/opt/k8s-server/kafka/kafka-test/test# vim zk.yaml 

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: zk
  namespace: boss
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: "registry.cn-shanghai.aliyuncs.com/study-03/zookeeper:1.0-3.4.10"
          resources:
            requests:
              memory: "1Gi"
              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: zookeeper-data
              mountPath: /bitnami/zookeeper
          readinessProbe:
            tcpSocket:
              port: 2181
            initialDelaySeconds: 20
            periodSeconds: 10
  volumeClaimTemplates:
    - metadata:
        name: zookeeper-data
      spec:
        accessModes: [ "ReadWriteOnce" ]
        storageClassName: "juicefs-sc"  # 根据集群调整
        resources:
          requests:
            storage: 8Gi

6、部署kafka集群

创建svc

root@ldap:/opt/k8s-server/kafka/kafka-test/test# cat kafka-service.yaml

apiVersion: v1
kind: Service
metadata:
  name: kafka-svc
  namespace: boss
  labels:
    app: kafka
spec:
  type: NodePort  # 将服务类型设置为 NodePort
  ports:
  - port: 9092
    name: server
    targetPort: 9092  # 映射到 Pod 内部的端口
    nodePort: 30092   # 设置一个指定的端口，或者让 Kubernetes 自动分配
  selector:
    app: kafka

部署kafka

root@ldap:/opt/k8s-server/kafka/kafka-test/test# vim kf.yaml 

apiVersion: v1
kind: Service
metadata:
  name: kafka-svc
  namespace: boss
  labels:
    app: kafka
spec:
  type: NodePort  # 将服务类型设置为 NodePort
  ports:
  - port: 9092
    name: server
    targetPort: 9092  # 映射到 Pod 内部的端口
    nodePort: 30092   # 设置一个指定的端口，或者让 Kubernetes 自动分配
  selector:
    app: kafka
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: kafka
  namespace: boss
spec:
  selector:
     matchLabels:
        app: kafka
  serviceName: kafka-svc
  replicas: 3
  template:
    metadata:
      labels:
        app: kafka
    spec:
      containers:
      - name: k8s-kafka
        imagePullPolicy: Always 
        image: registry.cn-hangzhou.aliyuncs.com/aliyun_0612/kafka:3.7.1
        resources:
          requests:
            memory: "600Mi"
            cpu: 500m
        ports:
        - containerPort: 9092
          name: server
        command:
        - sh
        - -c
        - "exec /opt/kafka/bin/kafka-server-start.sh /opt/kafka/config/server.properties --override broker.id=${HOSTNAME##*-} \
          --override listeners=PLAINTEXT://:9092 \
          --override zookeeper.connect=zk-cs.boss.svc.cluster.local:2181 \
          --override log.dir=/var/lib/kafka \
          --override auto.create.topics.enable=true \
          --override auto.leader.rebalance.enable=true \
          --override background.threads=10 \
          --override compression.type=producer \
          --override delete.topic.enable=false \
          --override leader.imbalance.check.interval.seconds=300 \
          --override leader.imbalance.per.broker.percentage=10 \
          --override log.flush.interval.messages=9223372036854775807 \
          --override log.flush.offset.checkpoint.interval.ms=60000 \
          --override log.flush.scheduler.interval.ms=9223372036854775807 \
          --override log.retention.bytes=-1 \
          --override log.retention.hours=168 \
          --override log.roll.hours=168 \
          --override log.roll.jitter.hours=0 \
          --override log.segment.bytes=1073741824 \
          --override log.segment.delete.delay.ms=60000 \
          --override message.max.bytes=1000012 \
          --override min.insync.replicas=1 \
          --override num.io.threads=8 \
          --override num.network.threads=3 \
          --override num.recovery.threads.per.data.dir=1 \
          --override num.replica.fetchers=1 \
          --override offset.metadata.max.bytes=4096 \
          --override offsets.commit.required.acks=-1 \
          --override offsets.commit.timeout.ms=5000 \
          --override offsets.load.buffer.size=5242880 \
          --override offsets.retention.check.interval.ms=600000 \
          --override offsets.retention.minutes=1440 \
          --override offsets.topic.compression.codec=0 \
          --override offsets.topic.num.partitions=50 \
          --override offsets.topic.replication.factor=3 \
          --override offsets.topic.segment.bytes=104857600 \
          --override queued.max.requests=500 \
          --override quota.consumer.default=9223372036854775807 \
          --override quota.producer.default=9223372036854775807 \
          --override replica.fetch.min.bytes=1 \
          --override replica.fetch.wait.max.ms=500 \
          --override replica.high.watermark.checkpoint.interval.ms=5000 \
          --override replica.lag.time.max.ms=10000 \
          --override replica.socket.receive.buffer.bytes=65536 \
          --override replica.socket.timeout.ms=30000 \
          --override request.timeout.ms=30000 \
          --override socket.receive.buffer.bytes=102400 \
          --override socket.request.max.bytes=104857600 \
          --override socket.send.buffer.bytes=102400 \
          --override unclean.leader.election.enable=true \
          --override zookeeper.session.timeout.ms=6000 \
          --override zookeeper.set.acl=false \
          --override broker.id.generation.enable=true \
          --override connections.max.idle.ms=600000 \
          --override controlled.shutdown.enable=true \
          --override controlled.shutdown.max.retries=3 \
          --override controlled.shutdown.retry.backoff.ms=5000 \
          --override controller.socket.timeout.ms=30000 \
          --override default.replication.factor=1 \
          --override fetch.purgatory.purge.interval.requests=1000 \
          --override group.max.session.timeout.ms=300000 \
          --override group.min.session.timeout.ms=6000 \
          --override inter.broker.protocol.version=2.2.0 \
          --override log.cleaner.backoff.ms=15000 \
          --override log.cleaner.dedupe.buffer.size=134217728 \
          --override log.cleaner.delete.retention.ms=86400000 \
          --override log.cleaner.enable=true \
          --override log.cleaner.io.buffer.load.factor=0.9 \
          --override log.cleaner.io.buffer.size=524288 \
          --override log.cleaner.io.max.bytes.per.second=1.7976931348623157E308 \
          --override log.cleaner.min.cleanable.ratio=0.5 \
          --override log.cleaner.min.compaction.lag.ms=0 \
          --override log.cleaner.threads=1 \
          --override log.cleanup.policy=delete \
          --override log.index.interval.bytes=4096 \
          --override log.index.size.max.bytes=10485760 \
          --override log.message.timestamp.difference.max.ms=9223372036854775807 \
          --override log.message.timestamp.type=CreateTime \
          --override log.preallocate=false \
          --override log.retention.check.interval.ms=300000 \
          --override max.connections.per.ip=2147483647 \
          --override num.partitions=3 \
          --override producer.purgatory.purge.interval.requests=1000 \
          --override replica.fetch.backoff.ms=1000 \
          --override replica.fetch.max.bytes=1048576 \
          --override replica.fetch.response.max.bytes=10485760 \
          --override reserved.broker.max.id=1000 "
        env:
        - name: KAFKA_HEAP_OPTS
          value : "-Xmx512M -Xms512M"
        - name: KAFKA_OPTS
          value: "-Dlogging.level=INFO"
        - name: KAFKA_ZOOKEEPER_SESSION_TIMEOUT_MS
          value: "6000"
        - name: KAFKA_ZOOKEEPER_CONNECTION_TIMEOUT_MS
          value: "10000"
        volumeMounts:
        - name: kafka-data
          mountPath: /bitnami/kafka
        readinessProbe:
          tcpSocket:
            port: 9092
          initialDelaySeconds: 30
          periodSeconds: 10
  volumeClaimTemplates:
  - metadata:
      name: kafka-data
    spec:
      accessModes: [ "ReadWriteOnce" ]
      storageClassName: "juicefs-sc"  # 根据集群调整
      resources:
        requests:
          storage: 8Gi

7、查看服务

root@ldap:/opt/k8s-server/kafka/kafka-test/test# kubectl get pod,svc -n boss