install ) kubernetes + Elasticsearch cluster (yaml로 설치)

K8s + Elastic Search pod 구축하기

Elastic Search 란?

* 실시간 검색/분석 기능 제공, 분산환경에 저장 되어있는 로그를 통합으로 수집합으로써 통합 데이터 저장소의 역할을 할 수 있고 로그의 라이프 사이클을 관리하여 효과적인 디스크 관리를 지원.
* MSA 환경에서 Telemetry는 더더욱 중요해지고 있고, Telemetry는 로깅, 모니터링, 추적 기능을 포괄하여 분산 트랜잭션 환경에서 효과적인 유지보수를 수행할 수 있도록 지원해주는 도구. 자동화된 수집 체계를 구성하는 것이 중요하다.
* 마스터 노드: 클러스터 관리, 인덱스 관리, 필요한 경우 새 마스터 선택을 담당
* Data 노드: 데이터 저장 전용인 반면 클라이언트 Pod는 수신 트래픽을 나머지 Pod로 전달하는 것 외에는 역할이 없다.
* Ingest 노드: 데이터 변환을 위한 노드
* Tribe 노드: 다중 클러스터 관리
* Client 노드: 복잡한 데이터의 조회 및 집계를 포함할 경우 사용하는 노드 등이 있다.

 

Elastic Search 설치

1) Namespace 생성
* $ vi elasticsearch-pv.yaml
apiVersion: v1
kind: Namespace
metadata:
  name: elasticsearch
      
2) YAML 파일 적용 및 Namespace 확인
* $ kubectl apply -f elasticsearch-pv.yaml
* $ kubectl get namespace
    
3) Elasticsearch master node 생성
3-1) Master node configmap 생성
$ vi elasticsearch-master-configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  namespace: elasticsearch
  name: elasticsearch-master-config
  labels:
    app: elasticsearch
    role: master
data:
  elasticsearch.yml: |-
    cluster.name: ${CLUSTER_NAME}
    node.name: ${NODE_NAME}
    discovery.seed_hosts: ${NODE_LIST}
    cluster.initial_master_nodes: ${MASTER_NODES}
    network.host: 0.0.0.0
    node:
      master: true
      data: false
      ingest: false
    xpack.security.enabled: false
    xpack.monitoring.collection.enabled: false
                
3-2) Master node service 생성
$ vi elasticsearch-master-service.yaml
apiVersion: v1
kind: Service
metadata:
  namespace: elasticsearch
  name: elasticsearch-master
  labels:
    app: elasticsearch
    role: master
spec:
  ports:
  - port: 9300
    name: transport
  selector:
    app: elasticsearch
    role: master
    
3-3) Master node deployment 생성
$ vi elasticsearch-master-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  namespace: elasticsearch
  name: elasticsearch-master
  labels:
    app: elasticsearch
    role: master
spec:
  replicas: 1
  selector:
    matchLabels:
      app: elasticsearch
      role: master
  template:
    metadata:
      labels:
        app: elasticsearch
        role: master
    spec:
      containers:
      - name: elasticsearch-master
        image: docker.elastic.co/elasticsearch/elasticsearch:7.3.0
        env:
        - name: CLUSTER_NAME
          value: elasticsearch
        - name: NODE_NAME
          value: elasticsearch-master
        - name: NODE_LIST
          value: elasticsearch-master,elasticsearch-data,elasticsearch-client
        - name: MASTER_NODES
          value: elasticsearch-master
        - name: "ES_JAVA_OPTS"
          value: "-Xms256m -Xmx256m"
        ports:
        - containerPort: 9300
          name: transport
        volumeMounts:
        - name: config
          mountPath: /usr/share/elasticsearch/config/elasticsearch.yml
          readOnly: true
          subPath: elasticsearch.yml
        - name: storage
          mountPath: /data
      volumes:
      - name: config
        configMap:
          name: elasticsearch-master-config
      - name: "storage"
        emptyDir:
          medium: ""
      initContainers:
      - name: increase-vm-max-map
        image: busybox
        command: ["sysctl", "-w", "vm.max_map_count=262144"]
        securityContext:
          privileged: true

3-4) Master node 생성 및 확인
$ kubectl apply -f elasticsearch-master-configmap.yaml -f elasticsearch-master-service.yaml -f elasticsearch-master-deployment.yaml 
$  kubectl get pods -n elasticsearch (Running 확인)

4) Elasticsearch Data node 생성
4-1) Data config 생성
$ vi elasticsearch-data-configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  namespace: elasticsearch
  name: elasticsearch-data-config
  labels:
    app: elasticsearch
    role: data
data:
  elasticsearch.yml: |-
    cluster.name: ${CLUSTER_NAME}
    node.name: ${NODE_NAME}
    discovery.seed_hosts: ${NODE_LIST}
    cluster.initial_master_nodes: ${MASTER_NODES}
    network.host: 0.0.0.0
    node:
      master: false
      data: true
      ingest: false
    xpack.security.enabled: false
    xpack.monitoring.collection.enabled: false
    
4-2) Data service 생성
$ vi elasticsearch-data-service.yaml
apiVersion: v1
kind: Service
metadata:
  namespace: elasticsearch
  name: elasticsearch-data
  labels:
    app: elasticsearch
    role: data
spec:
  ports:
  - port: 9300
    name: transport
  selector:
    app: elasticsearch
    role: data
    
4-3) Data statefulset 생성
$ vi elasticsearch-data-statefulset.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
  namespace: elasticsearch
  name: elasticsearch-data
  labels:
    app: elasticsearch
    role: data
spec:
  serviceName: "elasticsearch-data"
  selector:
    matchLabels:
      app: elasticsearch-data
      role: data
  replicas: 1
  template:
    metadata:
      labels:
        app: elasticsearch-data
        role: data
    spec:
      containers:
      - name: elasticsearch-data
        image: docker.elastic.co/elasticsearch/elasticsearch:7.3.0
        env:
        - name: CLUSTER_NAME
          value: elasticsearch
        - name: NODE_NAME
          value: elasticsearch-data
        - name: NODE_LIST
          value: elasticsearch-master,elasticsearch-data,elasticsearch-client
        - name: MASTER_NODES
          value: elasticsearch-master
        - name: "ES_JAVA_OPTS"
          value: "-Xms300m -Xmx300m"
        ports:
        - containerPort: 9300
          name: transport
        volumeMounts:
        - name: config
          mountPath: /usr/share/elasticsearch/config/elasticsearch.yml
          readOnly: true
          subPath: elasticsearch.yml
        - name: elasticsearch-data-persistent-storage
          mountPath: /data/db
      volumes:
      - name: config
        configMap:
          name: elasticsearch-data-config
      initContainers:
      - name: increase-vm-max-map
        image: busybox
        command: ["sysctl", "-w", "vm.max_map_count=262144"]
        securityContext:
          privileged: true
  volumeClaimTemplates:
  - metadata:
      name: elasticsearch-data-persistent-storage
      annotations:
        volume.beta.kubernetes.io/storage-class: "gp2"
    spec:
      accessModes: [ "ReadWriteOnce" ]
      storageClassName: standard
      resources:
        requests:
          storage: 10Gi
          
4-4) 적용 및 확인
$ kubectl apply -f elasticsearch-data-configmap.yaml -f elasticsearch-data-service.yaml -f elasticsearch-data-statefulset.yaml
$ kubectl get pods -n elasticsearch 
(master , data 2개 pod가 Running 이어야하는데 data는 pending 일 것이다. PV와 연결이 안되었기 때문)

5) Elasticsearch PV 생성
$ vi elasticsearch-persistentvolume.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
  namespace: elasticsearch
  name: elasticsearch-pv
  labels:
    name: elasticsearch
spec:
  storageClassName: standard 
  capacity:
    storage: 10Gi 
  volumeMode: Filesystem
  accessModes:
    - ReadWriteOnce
# PVC이름은 elasticsearch-data-statefulset의 volumeClaimTemplates의 name + pod명
  claimRef:
    namespace: elasticsearch
    name: elasticsearch-data-persistent-storage-elasticsearch-data-0
  persistentVolumeReclaimPolicy: Delete
  hostPath:
    path: /data/db
    type: DirectoryOrCreate
    
6) Elasticsearch Client node 생성
6-1) Client configmap 생성
$ vi elasticsearch-client-configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  namespace: elasticsearch
  name: elasticsearch-client-config
  labels:
    app: elasticsearch
    role: client
data:
  elasticsearch.yml: |-
    cluster.name: ${CLUSTER_NAME}
    node.name: ${NODE_NAME}
    discovery.seed_hosts: ${NODE_LIST}
    cluster.initial_master_nodes: ${MASTER_NODES}
    network.host: 0.0.0.0
    node:
      master: false
      data: false
      ingest: true
    xpack.security.enabled: false
    xpack.monitoring.collection.enabled: false
    
6-2) Client service 생성
$ vi elasticsearch-client-service.yaml
apiVersion: v1
kind: Service
metadata:
  namespace: elasticsearch
  name: elasticsearch-client
  labels:
    app: elasticsearch
    role: client
spec:
  ports:
  - port: 9200
    name: client
  - port: 9300
    name: transport
  selector:
    app: elasticsearch
    role: client
    
6-3) Client deployment 생성
$ vi elasticsearch-client-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  namespace: elasticsearch
  name: elasticsearch-client
  labels:
    app: elasticsearch
    role: client
spec:
  replicas: 1
  selector:
    matchLabels:
      app: elasticsearch
      role: client
  template:
    metadata:
      labels:
        app: elasticsearch
        role: client
    spec:
      containers:
      - name: elasticsearch-client
        image: docker.elastic.co/elasticsearch/elasticsearch:7.3.0
        env:
        - name: CLUSTER_NAME
          value: elasticsearch
        - name: NODE_NAME
          value: elasticsearch-client
        - name: NODE_LIST
          value: elasticsearch-master,elasticsearch-data,elasticsearch-client
        - name: MASTER_NODES
          value: elasticsearch-master
        - name: "ES_JAVA_OPTS"
          value: "-Xms256m -Xmx256m"
        ports:
        - containerPort: 9200
          name: client
        - containerPort: 9300
          name: transport
        volumeMounts:
        - name: config
          mountPath: /usr/share/elasticsearch/config/elasticsearch.yml
          readOnly: true
          subPath: elasticsearch.yml
        - name: storage
          mountPath: /data
      volumes:
      - name: config
        configMap:
          name: elasticsearch-client-config
      - name: "storage"
        emptyDir:
          medium: ""
      initContainers:
      - name: increase-vm-max-map
        image: busybox
        command: ["sysctl", "-w", "vm.max_map_count=262144"]
        securityContext:
          privileged: true
          
7) 적용 및 확인
$ kubectl apply -f elasticsearch-client-configmap.yaml -f elasticsearch-client-service.yaml -f elasticsearch-client-deployment.yaml
$ kubectl get svc -n elasticsearch -o wide

8) Service 생성 확인
$ kubectl get pods -n elasticsearch
Master , Client , Data node Running 확인

$ curl http://10.108.23.153:9200/_cluster/health?pretty
Cluster , status , node 생성 등 확인.

 

참고문헌

https://waspro.tistory.com/762