Spring boot sample app with attached prometheus_jmx

README.md

Intor

This is a spring boot sample app with attached [prometheus_jmx] (https://github.com/prometheus/jmx_exporter) agent. Agent exposes JVM metrics to 10245 ports. When the app is deployed on k8s cluster Prometheus automatically reads metrics and makes them available for query.

PS (If this gist will collect 100 starts I will make deeper blog post in this topic)

Build app

mvn clean package   
docker build -t prometheus-java-sample .

Test

docker run -d -p 8080:8080 -p 10254:10254 prometheus-java-sample
curl 127.0.0.1:8080
curl 127.0.0.1:10254/metrics 

Push to registry

eval $(aws ecr --profile=prod get-login --no-include-email --region eu-central-1)
docker tag prometheus-java-sample 11122233.dkr.ecr.eu-central-1.amazonaws.com/repo:prometheus-java-sample
docker push 11122233.dkr.ecr.eu-central-1.amazonaws.com/repo:prometheus-java-sample

Deploy to k8s

kubectl create -f app.yaml

Draw Graph

jvm_memory_bytes_used{app="pro-java-sample",area="heap"}

app.yaml

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: pro-java-sample
  labels:
    commit: latest
spec:
  replicas: 3
  selector:
    matchLabels:
      app: pro-java-sample
  template:
    metadata:
      labels:
        app: pro-java-sample
        commit: latest
    spec:
      containers:
      - name: pro-java-sample
        image: 111222333.dkr.ecr.eu-central-1.amazonaws.com/repo:prometheus-java-sample
        imagePullPolicy: Always
        ports:  
        - name: http-port
          containerPort: 8080
          protocol: TCP
        - name: jmx-port
          containerPort: 10254
---
apiVersion: v1
kind: Service
metadata:
  name: pro-java-sample
  labels:
    app: pro-java-sample
    commit: latest
  annotations:
    prometheus.io/port: "10254"
    prometheus.io/scrape: "true"
spec:
  ports:
  - name: http-port
    port: 8080
    targetPort: 8080
  - name: jmx-port 
    port: 10254
    targetPort: 10254
  selector:
    app: pro-java-sample
    commit: latest
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: pro-java-sample-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: "/"
spec:
   rules:
   - host: 
     http:
       paths:
       - path: /pro-java-sample
         backend:
           serviceName: pro-java-sample
           servicePort: 8080

config.yaml

---
username: 
password: 

rules:
- pattern: ".*"

Dockerfile

FROM openjdk:8-jre-alpine

RUN apk update && apk upgrade && apk --update add curl && rm -rf /tmp/* /var/cache/apk/*

ENV VERSION 0.11.0
ENV JAR jmx_prometheus_javaagent-$VERSION.jar

RUN mkdir -p /opt/jmx_exporter
RUN curl -L https://repo1.maven.org/maven2/io/prometheus/jmx/jmx_prometheus_javaagent/$VERSION/$JAR -o /opt/jmx_exporter/$JAR
RUN chmod +x /opt/jmx_exporter/$JAR
COPY config.yaml /opt/jmx_exporter/config.yaml

COPY target/HelloWorld-0.0.1-SNAPSHOT.jar /app.jar

EXPOSE 8080

EXPOSE 10254

CMD /usr/bin/java -Dspring.profiles.active=default -javaagent:/opt/jmx_exporter/$JAR=10254:/opt/jmx_exporter/config.yaml -jar /app.jar

HelloWorld.java

package com.bla.laa;

import org.springframework.boot.*;
import org.springframework.boot.autoconfigure.*;
import org.springframework.web.bind.annotation.*;

@SpringBootApplication
@RestController

public class HelloWorld {

	@RequestMapping("/")
	String home() {
		return "Hello World!";
	}

	public static void main(String[] args) throws Exception {
		SpringApplication.run(HelloWorld.class, args);
	}

}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.bla.laa</groupId>
    <artifactId>HelloWorld</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.10.RELEASE</version>
    </parent>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>