indrabasak / spring-k8s-prometheus

Initial revision.

Spring Boot Example with Kubernetes and Prometheus

This is example of using a Spring Boot application with Kubernetes, Prometheus, and Grafana.

Prometheus

Prometheus is an open source monitoring and alerting system. It's primarliy used for collecting and storing metrics. It also provides a graphical interface and a query language (PromQL) for querying metrics.

Prometheus uses a pull model for collecting metrics.

Maven Changes

In this example, Spotify's Dockerfile Maven Plugin is used for creating the Docker image. Spotify reccomends you to use this plugin instead of Docker Maven plugin.

Here is the change to this project's pom.xml.

<plugin>
    <groupId>com.spotify</groupId>
    <artifactId>dockerfile-maven-plugin</artifactId>
    <version>1.4.4</version>
    <executions>
        <execution>
            <id>default</id>
            <goals>
                <goal>build</goal>
                <goal>push</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <repository>basaki/spring-k8s-example</repository>
        <tag>${project.version}</tag>
        <buildArgs>
            <JAR_FILE>${project.build.finalName}.jar</JAR_FILE>
        </buildArgs>
    </configuration>
</plugin>

Build

To build the docker image, execute mvn clean install command from the parent directory:

$ mvn clean install
...

[INFO]  ---> Using cache
[INFO]  ---> f5d60c9391eb
[INFO] Step 8/8 : ENTRYPOINT ["java", "-Dapp.port=${app.port}", "-jar","/app.jar"]
[INFO] 
[INFO]  ---> Using cache
[INFO]  ---> 3e84ee5ba1cd
[INFO] [Warning] One or more build-args [JAR_FILE] were not consumed
[INFO] Successfully built 3e84ee5ba1cd
[INFO] Successfully tagged basaki/spring-k8s-example:1.0.0
[INFO] 
[INFO] Detected build of image with id 3e84ee5ba1cd
[INFO] Successfully built basaki/spring-k8s-example:1.0.0
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 52.519 s
[INFO] Finished at: 2018-10-21T19:55:36-07:00
[INFO] Final Memory: 67M/525M
[INFO] ------------------------------------------------------------------------

If the build is successful, it should create a new Docker image namedm basaki/spring-k8s-example:1.0.0.

Verify

You can list all the docker images by typing docker images in any terminal,

$ docker images 
REPOSITORY                                 TAG                 IMAGE ID            CREATED             SIZE
basaki/spring-k8s-example                  1.0.0               3e84ee5ba1cd        10 minutes ago      532MB
<none>                                     <none>              963c418de905        14 minutes ago      532MB
<none>                                     <none>              5eeb5eb716b4        29 minutes ago      532MB
...

If you just want to run the newly created Docker image without Kubernetes, please go here.

 kubectl create -f src/docker/namespace.yml 
namespace/example created

kubectl create -f src/docker/config.yml 
configmap/spring-prom-config created

docker login
Authenticating with existing credentials...
Login Succeeded

 kubectl get deployments -n example
NAME          DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
spring-prom   1         1         1            0           15m
MPORC02MT22Q:spring-k8s-prometheus indra.basak$ kubectl delete deployment spring-prom -n example
deployment.extensions "spring-prom" deleted

http://localhost:30090/graph

http://spring-prom.example.svc:8082/metrics

java_lang_GarbageCollector_LastGcInfo_memoryUsageAfterGc_max{instance="10.1.0.247:8082",job="svc-disc-endpoint",key="Code Cache",name="MarkSweepCompact",namespace="example",pod="spring-prom-9f5f48c74-vs77x",service="spring-prom"}

java_lang_GarbageCollector_LastGcInfo_memoryUsageAfterGc_max{instance="spring-prom.example.svc:8083",job="svc-disc-service",key="Compressed Class Space",name="Copy",namespace="example",service="spring-prom"}

ps auxw | grep kube-proxy
indra.basak      67603   0.0  0.0  4268056    808 s019  S+   11:15PM   0:00.00 grep kube-proxy