# Monitoring Hands-On

TIP

Demo Application 을 Kubernetes cluster에 배포
Kubernetes로 부터 Micrometer 정보를 discovery
Target으로 부터 Pod 및 JVM metrics 수집
Grafana dashboard에서 Pod 및 JVM metrics 정보를 시각화

# Step 01. Application

Demo Application 다운로드
1. git clone https://github.com/cnpst/sam-zcp-lab
2. cd sam-zcp-lab
Maven Dependency 설정 : micrometer 추가, spring-actuator

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<!-- Micormeter core dependecy  -->
<dependency>
	<groupId>io.micrometer</groupId>
	<artifactId>micrometer-core</artifactId>
</dependency>
<!-- Micrometer Prometheus registry  -->
<dependency>
	<groupId>io.micrometer</groupId>
	<artifactId>micrometer-registry-prometheus</artifactId>
</dependency>

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springboot(application.yaml) properties 수정

#Metrics related configurations
management:
  server:
    port: 8090
  endpoint:
    metrics:
      enabled: true
    prometheus:
      enabled: true
  endpoints:
    web:
      base-path: /
      exposure:
        include: "*"
  metrics:
    export:
      prometheus:
        enabled: true

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maven build mvn clean package

# Step 02. Docker Image

Dockerfile 작성

FROM openjdk:8-jdk-alpine
ADD target/sample-0.0.1-SNAPSHOT.jar app.jar
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom",”jar","/app.jar"]

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Docker Image Build
1. docker build -t spring-boot-monitoring-demo .
2. docker images
Application 실행/검증
1. docker run -p 8080:8080 -p 8090:8090 spring-boot-monitoring-demo
2. curl localhost:8080
Metric 확인 : curl localhost:8090/prometheus
Docker image Push to Registry
- docker tag spring-boot-monitoring-demo:[VERSION] [REPOSITORY_ADDRESS]/spring-boot-monitoring-demo:[VERSION]
- docker push [REPOSITORY_ADDRESS]/spring-boot-monitoring-demo:[VERSION]

# Step 03. Kubernetes Deploy

deployment.yaml
- spec.template.metadata.annotations.prometheus.io/scrape : Discorvery 대상 여부
- spec.template.metadata.annotations.prometheus.io/port : Discovery target port
- spec.template.metadata.annotations.prometheus.io/path : Discovery target path

...  
  template:
    metadata:      
...      
      annotations:        
        prometheus.io/scrape: "true"
        prometheus.io/port: "8090"
        prometheus.io/path: /prometheus
      spec:
        containers:
        - name: spring-boot-cicd-demo
          image: cloudzcp/spring-boot-monitoring-demo:latest
...

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Demo Application 배포
- kubectl apply -f k8s/deployment.yaml
Metric확인
- kubectl port-forward spring-boot-cicd-demo-5795695496-ljfkw 8090:8090
- curl localost:8090
- 결과
  - jvm_memory_used_bytes{area="heap",id="PS Survivor Space",} 4390912.0
  - jvm_memory_used_bytes{area="heap",id="PS Old Gen",} 1.6629768E7

# Step 04. Dashboard 구성

Import 메뉴 Click

Upload .json File Click
다운로드 받은 sam-zcp-lab 프로젝트 > grafana > micrometer-grafana-dashboard.json 파일 import
Options > prometheus combo box > prometheus data source 선택 > Import 버튼 선택

Heap Memory, Threads, Class Loading, Open File, GC 등에 대한 metrics을 그래프 형태로 조회
기타 Dashboard

Monitoring Hands-On