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apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: elasticsearch
  namespace: skywalking
  labels:
    service: elasticsearch
spec:
  serviceName: elasticsearch
  # NOTE: This is number of nodes that we want to run
  # you may update this
  replicas: 3
  selector:
    matchLabels:
      service: elasticsearch
  template:
    metadata:
      labels:
        service: elasticsearch
    spec:
      terminationGracePeriodSeconds: 300
      initContainers:
      # NOTE:
      # This is to fix the permission on the volume
      # By default elasticsearch container is not run as
      # non root user.
      # https://www.elastic.co/guide/en/elasticsearch/reference/current/docker.html#_notes_for_production_use_and_defaults
      - name: fix-the-volume-permission
        image: busybox
        command:
        - sh
        - -c
        - chown -R 1000:1000 /usr/share/elasticsearch/data
        securityContext:
          privileged: true
        volumeMounts:
        - name: data
          mountPath: /usr/share/elasticsearch/data
      # NOTE:
      # To increase the default vm.max_map_count to 262144
      # https://www.elastic.co/guide/en/elasticsearch/reference/current/docker.html#docker-cli-run-prod-mode
      - name: increase-the-vm-max-map-count
        image: busybox
        command:
        - sysctl
        - -w
        - vm.max_map_count=262144
        securityContext:
          privileged: true
      # To increase the ulimit
      # https://www.elastic.co/guide/en/elasticsearch/reference/current/docker.html#_notes_for_production_use_and_defaults
      - name: increase-the-ulimit
        image: busybox
        command:
        - sh
        - -c
        - ulimit -n 65536
        securityContext:
          privileged: true
      containers:
      - name: elasticsearch
        image: docker.elastic.co/elasticsearch/elasticsearch-oss:6.3.2
        ports:
        - containerPort: 9200
          name: http
        - containerPort: 9300
          name: tcp
        # NOTE: you can increase this resources
        resources:
          requests:
            memory: 8Gi
          limits:
            memory: 16Gi
        env:
          # NOTE: the cluster name; update this
          - name: cluster.name
            value: elasticsearch-cluster
          - name: node.name
            valueFrom:
              fieldRef:
                fieldPath: metadata.name
          # NOTE: This will tell the elasticsearch node where to connect to other nodes to form a cluster
          - name: discovery.zen.ping.unicast.hosts
            value: elasticsearch:9300
          # NOTE: You can increase the heap size
          - name: ES_JAVA_OPTS
            value: -Xms4g -Xmx4g
        volumeMounts:
        - name: data
          mountPath: /usr/share/elasticsearch/data
  volumeClaimTemplates:
  - metadata:
      name: data
    spec:
      accessModes:
        - ReadWriteOnce
      storageClassName: ssd
      # NOTE: You can increase the storage size
      resources:
        requests:
          storage: 500Gi
