[k8s]zookeeper集群在k8s的搭建(statefulset模式)-pod的调度

之前一直docker-compose跑zk集群,现在把它挪到k8s集群里.
docker-compose跑zk集群

zk集群in k8s部署

参考:
https://github.com/kubernetes/contrib/blob/master/statefulsets/zookeeper/zookeeper.yaml
https://kubernetes.io/docs/tutorials/stateful-application/zookeeper/

我修改了下默认的yaml
1.zk.yaml的存储,存储指向了我自己的nfs-backend
2.修改了image,拉倒了dockerhub

[root@m1 ~]# cat zookeeper.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:
      #    preferredDuringSchedulingIgnoredDuringExecution:
      #      cpu: "500m"
      #      - labelSelector:
      #          matchExpressions:
      #            - key: "app"
      #              operator: In
      #              values: 
      #              - zk
      #        topologyKey: "kubernetes.io/hostname"
      containers:
      - name: k8szk
        imagePullPolicy: Always
        image: lanny/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
      annotations:
        #volume.alpha.kubernetes.io/storage-class: "managed-nfs-storage" #不同版本这里引用的alpha/beta不同注意
        volume.beta.kubernetes.io/storage-class: "managed-nfs-storage"
    spec:
      accessModes: ["ReadWriteOnce"]
      resources:
        requests:
          storage: 1Gi

遇到的问题: zk-3一直pending

第三台老pending(我只有2个node节点)

$ kubectl get po --all-namespaces
cNAMESPACE       NAME                                        READY     STATUS    RESTARTS   AGE       IP               NODE        LABELS
default         zk-0                                        1/1       Running   0          11m       10.2.30.5        n2.ma.com   app=zk,controller-revision-hash=zk-1636685058
default         zk-1                                        1/1       Running   0          10m       10.2.54.3        n1.ma.com   app=zk,controller-revision-hash=zk-1636685058
default         zk-2                                        0/1       Pending   0          10m                        app=zk,controller-revision-hash=zk-1636685058

zk-3一直pending解决(调度策略)

zk的yaml的默认调度策略是这样的(每个物理节点对应一个zk节点,所以第三台zk节点一直pending)

kubectl describe po zk-2
...
No nodes are available that match all of the following predicates:: MatchInterPodAffinity (2).

细看了下zk的yaml他的调度策略是这样的,每节点一个zk节点,而我只有2个node,因此暂时先把它注释掉

      #affinity:
      #  podAntiAffinity:
      #    #requiredDuringSchedulingIgnoredDuringExecution:
      #    preferredDuringSchedulingIgnoredDuringExecution:
      #      cpu: "500m"
      #      - labelSelector:
      #          matchExpressions:
      #            - key: "app"
      #              operator: In
      #              values: 
      #              - zk
      #        topologyKey: "kubernetes.io/hostname"

节点亲和调度 pod亲和调度

集群内如何访问headless服务?

思路: 可以新建一个非headless的svc.用于针对用户访问.