kubernetes搭建es集群

问题描述：（es环境为7.2.0）
新版废弃了原先discovery.zen.ping.unicast.hosts及discovery.zen.minimum_master_nodes的探测方式，而是改为了discovery.seed_hosts及cluster.initial_master_nodes，其中第一项换汤不换药，值还是一样的，我们还是填内部服务域名，而后一项就有点恶心了，这项在实体服务器上配置没任何问题，把符合master节点的ip或主机名配进去就可以了，但在k8s环境下，master节点的ip是pod ip，随即分配的，主机名由于是deployment下部署的，主机名的尾巴也是随机字符，同样无法指定，不配的话各节点服务器无法选举master，无法组成集群。

办法：将es-master部署方式由depolyment调整至statefulset，这样就解决了主机名无法指定的问题，配置如下：

- name: cluster.initial_master_nodes
value: "elasticsearch-master-0,elasticsearch-master-1,elasticsearch-master-2"

下面是配置文件，全放一起了

---
kind: StatefulSet
metadata:
  labels:
    app: elasticsearch
    role: master
  name: elasticsearch-master
  namespace: elastic
spec:
  replicas: 2
  serviceName: elasticsearch-master
  selector:
    matchLabels:
      app: elasticsearch
      role: master
  template:
    metadata:
      labels:
        app: elasticsearch
        role: master
    spec:
      serviceAccountName: elasticsearch-admin
      restartPolicy: Always
      securityContext:
        fsGroup: 1000
      containers:
        - name: elasticsearch-master
          image: elasticsearch:7.2.0
          imagePullPolicy: IfNotPresent
          securityContext:
            privileged: true
          ports:
            - containerPort: 9200
              protocol: TCP
            - containerPort: 9200
              protocol: TCP
          env:
            - name: cluster.name
              value: "es_cluster"
            - name: node.master
              value: "true"
            - name: node.data
              value: "false"
            - name: discovery.seed_hosts 
              value: "elasticsearch-discovery" 
            - name: cluster.initial_master_nodes 
              value: "elasticsearch-master-0,elasticsearch-master-1" 
            - name: node.ingest
              value: "false"
            - name: ES_JAVA_OPTS
              value: "-Xms1g -Xmx1g" 
              
---
kind: Service
apiVersion: v1
metadata:
 labels:
   app: elasticsearch
 name: elasticsearch-discovery
 namespace: elastic
spec:
 ports:
   - port: 9300
     targetPort: 9300
 selector:
   app: elasticsearch
   role: master
---
apiVersion: v1
kind: Service
metadata:
 name: elasticsearch-data-service
 namespace: elastic
 labels:
   app: elasticsearch
   role: data
spec:
 ports:
   - port: 9200
     name: outer
   - port: 9300
     name: inner
 clusterIP: None
 selector:
   app: elasticsearch
   role: data
---

kind: StatefulSet
metadata:
  labels:
    app: elasticsearch
    role: master
  name: elasticsearch-data
  namespace: elastic
spec:
  replicas: 2
  serviceName: elasticsearch-data
  selector:
    matchLabels:
      app: elasticsearch
      role: data
  template:
    metadata:
      labels:
        app: elasticsearch
        role: data
    spec:
      serviceAccountName: elasticsearch-admin
      restartPolicy: Always
      securityContext:
        fsGroup: 1000
      containers:
        - name: elasticsearch-data
          image: elasticsearch:7.2.0
          imagePullPolicy: IfNotPresent
          securityContext:
            privileged: true
          ports:
            - containerPort: 9200
              protocol: TCP
            - containerPort: 9300
              protocol: TCP
          env:
            - name: cluster.name
              value: "es_cluster"
            - name: node.master
              value: "fasle"
            - name: node.data
              value: "true"
            - name: discovery.seed_hosts # 
              value: "elasticsearch-discovery" 
            - name: cluster.initial_master_nodes 
              value: "elasticsearch-master-0,elasticsearch-master-1" 
            - name: node.ingest
              value: "false"
            - name: ES_JAVA_OPTS
              value: "-Xms1g -Xmx1g" 

可以建议大家用rancher进行部署，当然前提得知道es集群搭建的原理，我用rancher搭建的时候就不太熟悉rancher的操作，走了很多弯路。（es的环境变量可以用configmap进行代替，两者都可以使用的）