[리소스 로깅과 모니터링] EFK를 활용한 k8s 로그 모니터링 개요와 시스템 구축

EFK 설치 환경

• 쿠버네티스에서 EFK를 사용하면 도커의 각 컨테이너 로그를 수집하고 시각화, 분석 가능
• 쿠버네티스 메모리 8GB 이상 필요
• 엘라스틱 스택은 주로 비츠나 로그스태시를 사용하는 것이 일반적
• 쿠버네티스에서는 fluentd를 사용해서 수집하는 것이 유행

E: Elasticsearch 데이터베이스 & 검색엔진
L: Logstash 데이터 수집기, 파이프라인
K: Kibana 그라파나의 역할, 대시보드 (SIEM, 머신러닝, Alert)

# elasticsearch.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: elasticsearch
  namespace: elastic
  labels:
    app: elasticsearch
spec:
  replicas: 1
  selector:
    matchLabels:
      app: elasticsearch
  template:
    metadata:
      labels:
        app: elasticsearch
    spec:
      containers:
      - name: elasticsearch
        image: elastic/elasticsearch:7.14.1
        env:
        - name: discovery.type
          value: single-node
        ports:
        - containerPort: 9200
        - containerPort: 9300
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app: elasticsearch
  name: elasticsearch-svc
  namespace: elastic
spec:
  ports:
  - name: elasticsearch-rest
    nodePort: 30920
    port: 9200
    protocol: TCP
    targetPort: 9200
  - name: elasticsearch-nodecom
    nodePort: 30930
    port: 9300
    protocol: TCP
    targetPort: 9300
  selector:
    app: elasticsearch

# fluentd.yaml
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: fluentd
  namespace: kube-system

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: fluentd
  namespace: kube-system
rules:
- apiGroups:
  - ""
  resources:
  - pods
  - namespaces
  verbs:
  - get
  - list
  - watch

---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: fluentd
roleRef:
  kind: ClusterRole
  name: fluentd
  apiGroup: rbac.authorization.k8s.io
subjects:
- kind: ServiceAccount
  name: fluentd
  namespace: kube-system
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: fluentd
  namespace: kube-system
  labels:
    k8s-app: fluentd-logging
    version: v1
spec:
  selector:
    matchLabels:
      k8s-app: fluentd-logging
      version: v1
  template:
    metadata:
      labels:
        k8s-app: fluentd-logging
        version: v1
    spec:
      serviceAccount: fluentd
      serviceAccountName: fluentd
      tolerations:
      - key: node-role.kubernetes.io/master
        effect: NoSchedule
      containers:
      - name: fluentd
        image: fluent/fluentd-kubernetes-daemonset:v1-debian-elasticsearch
        env:
        - name:  FLUENT_ELASTICSEARCH_HOST
          value: elasticsearch-svc.elastic
        - name:  FLUENT_ELASTICSEARCH_PORT
          value: "9200"
        - name: FLUENT_ELASTICSEARCH_SCHEME
          value: http
        resources:
          limits:
            memory: 200Mi
          requests:
            cpu: 100m
            memory: 200Mi
        volumeMounts:
        - name: varlog
          mountPath: /var/log
        - name: varlibdockercontainers
          mountPath: /var/lib/docker/containers
          readOnly: true
      terminationGracePeriodSeconds: 30
      volumes:
      - name: varlog
        hostPath:
          path: /var/log
      - name: varlibdockercontainers
        hostPath:
          path: /var/lib/docker/containers

# kibana.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: kibana
  namespace: elastic
  labels:
    app: kibana
spec:
  replicas: 1
  selector:
    matchLabels:
      app: kibana
  template:
    metadata:
      labels:
        app: kibana
    spec:
      containers:
      - name: kibana
        image: elastic/kibana:7.14.1
        env:
        - name: SERVER_NAME
          value: kibana.kubenetes.example.com
        - name: ELASTICSEARCH_HOSTS
          value: http://elasticsearch-svc:9200
        ports:
        - containerPort: 5601
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app: kibana
  name: kibana-svc
  namespace: elastic
spec:
  ports:
  - nodePort: 30561
    port: 5601
    protocol: TCP
    targetPort: 5601
  selector:
    app: kibana