StatefulSet在ZooKeeper和Kafka的实践

K8s的版本是1.7.6

采用nfs的nas存储模式

NFS的问题

• 建立zk集群的时候总是发现myid绑定一个id,先describe pod确认每个绑定不同的pvc,然后就确认是pv创建的问题，pv创建不能直接挂在一个大的存储上面，因为大家最后的目录相同/var/lib/zookeeper/data目录，所以无论哪个pvc挂上去都是同样的目录,解决办法，建立不同的存储挂载目录，然后分别挂载pv
• 建立pv的时候，指明storageClassName,比如

apiVersion: v1
kind: PersistentVolume
metadata:
    name: pv0003
spec:
    capacity:
      storage: 5Gi
    accessModes:
      - ReadWriteOnce
    persistentVolumeReclaimPolicy: Recycle
    storageClassName: nas-zk
    nfs:
      path: /k8s/weblogic
      server: 192.168.0.103

在使用pvc的时候，也指明storageClassName,比如

 volumeClaimTemplates:
  - metadata:
      name: datadir
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 10Gi
      storageClassName: nas-zk

这样就可以控制zk的存储使用的是带这个标签的pv

• pv和pvc的accessModes一定要保持一致，否则找不到

建立zk集群脚本

https://github.com/kubernetes/contrib/blob/master/statefulsets/zookeeper/zookeeper.yaml

也可以参考

https://kubernetes.io/docs/tutorials/stateful-application/zookeeper/

但是我的机器版本是1.7.6运行起来总是有问题,居然都不是一个个建立起来，而是一次性把所有的都建立起来。

改用脚本和镜像后问题才消失。

zk集群验证

for i in 0 1 2; do kubectl exec zk-$i -- hostname; done

zk-0
zk-1
zk-2

for i in 0 1 2; do echo "myid zk-$i";kubectl exec zk-$i -- cat /var/lib/zookeeper/data/myid; done

myid zk-0
1
myid zk-1
2
myid zk-2
3

for i in 0 1 2; do kubectl exec zk-$i -- hostname -f; done
zk-0.zk-hs.default.svc.cluster.local
zk-1.zk-hs.default.svc.cluster.local
zk-2.zk-hs.default.svc.cluster.local

暴露服务给集群外

kubectl label pod zk-0 zkInst=0                                                                          
kubectl label pod zk-1 zkInst=1       
kubectl label pod zk-2 zkInst=2
                                                                      
kubectl expose po zk-0 --port=2181 --target-port=2181 --name=zk-0 --selector=zkInst=0 --type=NodePort
kubectl expose po zk-1 --port=2181 --target-port=2181 --name=zk-1 --selector=zkInst=1 --type=NodePort
kubectl expose po zk-2 --port=2181 --target-port=2181 --name=zk-2 --selector=zkInst=2 --type=NodePort

建立kafka集群

构建脚本

https://github.com/kubernetes/contrib/blob/master/statefulsets/kafka/kafka.yaml

验证

root@kafka-0:/opt/kafka/config# kafka-topics.sh --create 
> --topic test 
> --zookeeper zoo-0.zk.default.svc.cluster.local:2181,zoo-1.zk.default.svc.cluster.local:2181,zoo-2.zk.default.svc.cluster.local:2181 
> --partitions 3 
> --replication-factor 2

Created topic "test".

root@kafka-0:/opt/kafka/config# kafka-console-consumer.sh --topic test --bootstrap-server localhost:9093

root@kafka-1:/# kafka-console-producer.sh --topic test --broker-list localhost:9093                                                             
I like kafka
hello world

#在消费者侧显示为：
I like kafka
hello world

参考

https://cloud.tencent.com/developer/article/1005492

zk.yaml

---
apiVersion: v1
kind: Service
metadata:
  name: zk-svc
  labels:
    app: zk-svc
spec:
  ports:
  - port: 2888
    name: server
  - port: 3888
    name: leader-election
  clusterIP: None
  selector:
    app: zk
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: zk-cm
data:
  jvm.heap: "1G"
  tick: "2000"
  init: "10"
  sync: "5"
  client.cnxns: "60"
  snap.retain: "3"
  purge.interval: "0"
---
apiVersion: policy/v1beta1
kind: PodDisruptionBudget
metadata:
  name: zk-pdb
spec:
  selector:
    matchLabels:
      app: zk
  minAvailable: 2
---
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
  name: zk
spec:
  serviceName: zk-svc
  replicas: 3
  template:
    metadata:
      labels:
        app: zk
    spec:
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                matchExpressions:
                  - key: "app"
                    operator: In
                    values: 
                    - zk
              topologyKey: "kubernetes.io/hostname"
      containers:
      - name: k8szk
        imagePullPolicy: Always
        image: gcr.io/google_samples/k8szk:v3
        resources:
          requests:
            memory: "2Gi"
            cpu: "500m"
        ports:
        - containerPort: 2181
          name: client
        - containerPort: 2888
          name: server
        - containerPort: 3888
          name: leader-election
        env:
        - name : ZK_REPLICAS
          value: "3"
        - name : ZK_HEAP_SIZE
          valueFrom:
            configMapKeyRef:
                name: zk-cm
                key: jvm.heap
        - name : ZK_TICK_TIME
          valueFrom:
            configMapKeyRef:
                name: zk-cm
                key: tick
        - name : ZK_INIT_LIMIT
          valueFrom:
            configMapKeyRef:
                name: zk-cm
                key: init
        - name : ZK_SYNC_LIMIT
          valueFrom:
            configMapKeyRef:
                name: zk-cm
                key: tick
        - name : ZK_MAX_CLIENT_CNXNS
          valueFrom:
            configMapKeyRef:
                name: zk-cm
                key: client.cnxns
        - name: ZK_SNAP_RETAIN_COUNT
          valueFrom:
            configMapKeyRef:
                name: zk-cm
                key: snap.retain
        - name: ZK_PURGE_INTERVAL
          valueFrom:
            configMapKeyRef:
                name: zk-cm
                key: purge.interval
        - name: ZK_CLIENT_PORT
          value: "2181"
        - name: ZK_SERVER_PORT
          value: "2888"
        - name: ZK_ELECTION_PORT
          value: "3888"
        command:
        - sh
        - -c
        - zkGenConfig.sh && zkServer.sh start-foreground
        readinessProbe:
          exec:
            command:
            - "zkOk.sh"
          initialDelaySeconds: 10
          timeoutSeconds: 5
        livenessProbe:
          exec:
            command:
            - "zkOk.sh"
          initialDelaySeconds: 10
          timeoutSeconds: 5
        volumeMounts:
        - name: datadir
          mountPath: /var/lib/zookeeper
      securityContext:
        runAsUser: 1000
        fsGroup: 1000
  volumeClaimTemplates:
  - metadata:
      name: datadir
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 10Gi

kafka.yaml

---
apiVersion: v1
kind: Service
metadata:
  name: kafka-svc
  labels:
    app: kafka
spec:
  ports:
  - port: 9093
    name: server
  clusterIP: None
  selector:
    app: kafka
---
apiVersion: policy/v1beta1
kind: PodDisruptionBudget
metadata:
  name: kafka-pdb
spec:
  selector:
    matchLabels:
      app: kafka
  minAvailable: 2
---
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
  name: kafka
spec:
  serviceName: kafka-svc
  replicas: 3
  template:
    metadata:
      labels:
        app: kafka
    spec:
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                matchExpressions:
                  - key: "app"
                    operator: In
                    values: 
                    - kafka
              topologyKey: "kubernetes.io/hostname"
        podAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
             - weight: 1
               podAffinityTerm:
                 labelSelector:
                    matchExpressions:
                      - key: "app"
                        operator: In
                        values: 
                        - zk
                 topologyKey: "kubernetes.io/hostname"
      terminationGracePeriodSeconds: 300
      containers:
      - name: k8skafka
        imagePullPolicy: Always
        image: gcr.io/google_samples/k8skafka:v1
        resources:
          requests:
            memory: "1Gi"
            cpu: 500m
        ports:
        - containerPort: 9093
          name: server
        command:
        - sh
        - -c
        - "exec kafka-server-start.sh /opt/kafka/config/server.properties --override broker.id=${HOSTNAME##*-} 
          --override listeners=PLAINTEXT://:9093 
          --override zookeeper.connect=zk-0.zk-svc.default.svc.cluster.local:2181,zk-1.zk-svc.default.svc.cluster.local:2181,zk-2.zk-svc.default.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=0.10.2-IV0 
          --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=1 
          --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"
        volumeMounts:
        - name: datadir
          mountPath: /var/lib/kafka
        readinessProbe:
          exec:
           command: 
            - sh 
            - -c 
            - "/opt/kafka/bin/kafka-broker-api-versions.sh --bootstrap-server=localhost:9093"
      securityContext:
        runAsUser: 1000
        fsGroup: 1000
  volumeClaimTemplates:
  - metadata:
      name: datadir
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 10Gi