教你在Kubernetes中快速部署ES集群

摘要：ES集群是进行大数据存储和分析，快速检索的利器，本文简述了ES的集群架构，并提供了在Kubernetes中快速部署ES集群的样例；对ES集群的监控运维工具进行了介绍，并提供了部分问题定位经验，最后总结了常用ES集群的API调用方法。

本文分享自华为云社区《Kubernetes中部署ES集群及运维》，原文作者：minucas。

ES集群架构：

ES集群分为单点模式和集群模式，其中单点模式一般在生产环境不推荐使用，推荐使用集群模式部署。其中集群模式又分为Master节点与Data节点由同一个节点承担，以及Master节点与Data节点由不同节点承担的部署模式。Master节点与Data节点分开的部署方式可靠性更强。下图为ES集群的部署架构图：

采用K8s进行ES集群部署：

1、采用k8s statefulset部署，可快速的进行扩缩容es节点，本例子采用 3 Master Node + 12 Data Node 方式部署
2、通过k8s service配置了对应的域名和服务发现，确保集群能自动联通和监控

kubectl -s http://ip:port create -f es-master.yaml
kubectl -s http://ip:port create -f es-data.yaml
kubectl -s http://ip:port create -f es-service.yaml

es-master.yaml:

apiVersion: apps/v1
kind: StatefulSet
metadata:
  labels:
    addonmanager.kubernetes.io/mode: Reconcile
    k8s-app: es
    kubernetes.io/cluster-service: "true"
    version: v6.2.5
  name: es-master
  namespace: default
spec:
  podManagementPolicy: OrderedReady
  replicas: 3
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      k8s-app: es
      version: v6.2.5
  serviceName: es
  template:
    metadata:
      labels:
        k8s-app: camp-es
        kubernetes.io/cluster-service: "true"
        version: v6.2.5
    spec:
      containers:
      - env:
        - name: NAMESPACE
          valueFrom:
            fieldRef:
              apiVersion: v1
              fieldPath: metadata.namespace
        - name: ELASTICSEARCH_SERVICE_NAME
          value: es
        - name: NODE_MASTER
          value: "true"
        - name: NODE_DATA
          value: "false"
        - name: ES_HEAP_SIZE
          value: 4g
        - name: ES_JAVA_OPTS
          value: -Xmx4g -Xms4g
        - name: cluster.name
          value: es
        image: elasticsearch:v6.2.5
        imagePullPolicy: Always
        name: es
        ports:
        - containerPort: 9200
          hostPort: 9200
          name: db
          protocol: TCP
        - containerPort: 9300
          hostPort: 9300
          name: transport
          protocol: TCP
        resources:
          limits:
            cpu: "6"
            memory: 12Gi
          requests:
            cpu: "4"
            memory: 8Gi
        securityContext:
          capabilities:
            add:
            - IPC_LOCK
            - SYS_RESOURCE
        volumeMounts:
        - mountPath: /data
          name: es
      - command:
        - /bin/elasticsearch_exporter
        - -es.uri=http://localhost:9200
        - -es.all=true
        image: elasticsearch_exporter:1.0.2
        imagePullPolicy: IfNotPresent
        livenessProbe:
          failureThreshold: 3
          httpGet:
            path: /health
            port: 9108
            scheme: HTTP
          initialDelaySeconds: 30
          periodSeconds: 10
          successThreshold: 1
          timeoutSeconds: 10
        name: es-exporter
        ports:
        - containerPort: 9108
          hostPort: 9108
          protocol: TCP
        readinessProbe:
          failureThreshold: 3
          httpGet:
            path: /health
            port: 9108
            scheme: HTTP
          initialDelaySeconds: 10
          periodSeconds: 10
          successThreshold: 1
          timeoutSeconds: 10
        resources:
          limits:
            cpu: 100m
            memory: 128Mi
          requests:
            cpu: 25m
            memory: 64Mi
        securityContext:
          capabilities:
            drop:
            - SETPCAP
            - MKNOD
            - AUDIT_WRITE
            - CHOWN
            - NET_RAW
            - DAC_OVERRIDE
            - FOWNER
            - FSETID
            - KILL
            - SETGID
            - SETUID
            - NET_BIND_SERVICE
            - SYS_CHROOT
            - SETFCAP
          readOnlyRootFilesystem: true
      dnsPolicy: ClusterFirst
      initContainers:
      - command:
        - /sbin/sysctl
        - -w
        - vm.max_map_count=262144
        image: alpine:3.6
        imagePullPolicy: IfNotPresent
        name: elasticsearch-logging-init
        resources: {}
        securityContext:
          privileged: true
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      volumes:
      - hostPath:
          path: /Data/es
          type: DirectoryOrCreate
        name: es

es-data.yaml

apiVersion: apps/v1
kind: StatefulSet
metadata:
  labels:
    addonmanager.kubernetes.io/mode: Reconcile
    k8s-app: es
    kubernetes.io/cluster-service: "true"
    version: v6.2.5
  name: es-data
  namespace: default
spec:
  podManagementPolicy: OrderedReady
  replicas: 12
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      k8s-app: es
      version: v6.2.5
  serviceName: es
  template:
    metadata:
      labels:
        k8s-app: es
        kubernetes.io/cluster-service: "true"
        version: v6.2.5
    spec:
      containers:
      - env:
        - name: NAMESPACE
          valueFrom:
            fieldRef:
              apiVersion: v1
              fieldPath: metadata.namespace
        - name: ELASTICSEARCH_SERVICE_NAME
          value: es
        - name: NODE_MASTER
          value: "false"
        - name: NODE_DATA
          value: "true"
        - name: ES_HEAP_SIZE
          value: 16g
        - name: ES_JAVA_OPTS
          value: -Xmx16g -Xms16g
        - name: cluster.name
          value: es
        image: elasticsearch:v6.2.5
        imagePullPolicy: Always
        name: es
        ports:
        - containerPort: 9200
          hostPort: 9200
          name: db
          protocol: TCP
        - containerPort: 9300
          hostPort: 9300
          name: transport
          protocol: TCP
        resources:
          limits:
            cpu: "8"
            memory: 32Gi
          requests:
            cpu: "7"
            memory: 30Gi
        securityContext:
          capabilities:
            add:
            - IPC_LOCK
            - SYS_RESOURCE
        volumeMounts:
        - mountPath: /data
          name: es
      - command:
        - /bin/elasticsearch_exporter
        - -es.uri=http://localhost:9200
        - -es.all=true
        image: elasticsearch_exporter:1.0.2
        imagePullPolicy: IfNotPresent
        livenessProbe:
          failureThreshold: 3
          httpGet:
            path: /health
            port: 9108
            scheme: HTTP
          initialDelaySeconds: 30
          periodSeconds: 10
          successThreshold: 1
          timeoutSeconds: 10
        name: es-exporter
        ports:
        - containerPort: 9108
          hostPort: 9108
          protocol: TCP
        readinessProbe:
          failureThreshold: 3
          httpGet:
            path: /health
            port: 9108
            scheme: HTTP
          initialDelaySeconds: 10
          periodSeconds: 10
          successThreshold: 1
          timeoutSeconds: 10
        resources:
          limits:
            cpu: 100m
            memory: 128Mi
          requests:
            cpu: 25m
            memory: 64Mi
        securityContext:
          capabilities:
            drop:
            - SETPCAP
            - MKNOD
            - AUDIT_WRITE
            - CHOWN
            - NET_RAW
            - DAC_OVERRIDE
            - FOWNER
            - FSETID
            - KILL
            - SETGID
            - SETUID
            - NET_BIND_SERVICE
            - SYS_CHROOT
            - SETFCAP
          readOnlyRootFilesystem: true
      dnsPolicy: ClusterFirst
      initContainers:
      - command:
        - /sbin/sysctl
        - -w
        - vm.max_map_count=262144
        image: alpine:3.6
        imagePullPolicy: IfNotPresent
        name: elasticsearch-logging-init
        resources: {}
        securityContext:
          privileged: true
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      volumes:
      - hostPath:
          path: /Data/es
          type: DirectoryOrCreate
        name: es

es-service.yaml

apiVersion: v1
kind: Service
metadata:
  labels:
    addonmanager.kubernetes.io/mode: Reconcile
    k8s-app: es
    kubernetes.io/cluster-service: "true"
    kubernetes.io/name: Elasticsearch
  name: es
  namespace: default
spec:
  clusterIP: None
  ports:
  - name: es
    port: 9200
    protocol: TCP
    targetPort: 9200
  - name: exporter
    port: 9108
    protocol: TCP
    targetPort: 9108
  selector:
    k8s-app: es
  sessionAffinity: None
  type: ClusterIP

ES集群监控

工欲善其事必先利其器，中间件的运维首先要有充分的监控手段，ES集群的监控常用的三种监控手段：exporter、eshead、kopf，由于ES集群是采用k8s架构部署，很多特性都会结合k8s来开展

Grafana监控

通过k8s部署es-exporter将监控metrics导出，prometheus采集监控数据，grafana定制dashboard展示

ES-head组件

github地址：https://github.com/mobz/elasticsearch-head
ES-head组件可通过谷歌浏览器应用商店搜索安装，使用Chrome插件可查看ES集群的情况

Cerebro（kopf）组件

github地址：https://github.com/lmenezes/cerebro
 

ES集群问题处理

ES配置

资源配置：关注ES的CPU、Memory以及Heap Size，Xms Xmx的配置，建议如机器是8u32g内存的情况下，堆内存和Xms Xmx配置为50%，官网建议单个node的内存不要超过64G

索引配置：由于ES检索通过索引来定位，检索的时候ES会将相关的索引数据装载到内存中加快检索速度，因此合理的对索引进行设置对ES的性能影响很大，当前我们通过按日期创建索引的方法（个别数据量小的可不分割索引）

ES负载

CPU和Load比较高的节点重点关注，可能的原因是shard分配不均匀，此时可手动讲不均衡的shard relocate一下

shard配置

shard配置最好是data node数量的整数倍，shard数量不是越多越好，应该按照索引的数据量合理进行分片，确保每个shard不要超过单个data node分配的堆内存大小，比如数据量最大的index单日150G左右，分为24个shard，计算下来单个shard大小大概6-7G左右

副本数建议为1，副本数过大，容易导致数据的频繁relocate，加大集群负载

删除异常index

curl -X DELETE "10.64.xxx.xx:9200/szv-prod-ingress-nginx-2021.05.01"

索引名可使用进行正则匹配进行批量删除，如：-2021.05.*

节点负载高的另一个原因

在定位问题的时候发现节点数据shard已经移走但是节点负载一直下不去，登入节点使用top命令发现节点kubelet的cpu占用非常高，重启kubelet也无效，重启节点后负载才得到缓解

ES集群常规运维经验总结（参考官网）

查看集群健康状态

ES集群的健康状态分为三种：Green、Yellow、Red。

• Green(绿色)：集群健康；
• Yellow(黄色)：集群非健康，但在负载允许范围内可自动rebalance恢复；
• Red(红色)：集群存在问题，有部分数据未就绪，至少有一个主分片未分配成功。

可通过API查询集群的健康状态及未分配的分片：

GET _cluster/health
{
  "cluster_name": "camp-es",
  "status": "green",
  "timed_out": false,
  "number_of_nodes": 15,
  "number_of_data_nodes": 12,
  "active_primary_shards": 2176,
  "active_shards": 4347,
  "relocating_shards": 0,
  "initializing_shards": 0,
  "unassigned_shards": 0,
  "delayed_unassigned_shards": 0,
  "number_of_pending_tasks": 0,
  "number_of_in_flight_fetch": 0,
  "task_max_waiting_in_queue_millis": 0,
  "active_shards_percent_as_number": 100
}

查看pending tasks：

GET /_cat/pending_tasks

其中 priority 字段则表示该 task 的优先级

查看分片未分配原因

GET _cluster/allocation/explain

其中reason 字段表示哪种原因导致的分片未分配，detail 表示详细未分配的原因

查看所有未分配的索引和主分片：

GET /_cat/indices?v&health=red

查看哪些分片出现异常

curl -s http://ip:port/_cat/shards | grep UNASSIGNED

重新分配一个主分片：

POST _cluster/reroute?pretty" -d '{
    "commands" : [
        {
          "allocate_stale_primary" : {
              "index" : "xxx",
              "shard" : 1,
              "node" : "12345...",
              "accept_data_loss": true
          }
        }
    ]
}

其中node为es集群节点的id，可以通过curl ‘ip:port/_node/process?pretty’ 进行查询

降低索引的副本的数量

PUT /szv_ingress_*/settings
{
  "index": {
    "number_of_replicas": 1
  }
}

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