I am new to docker, kubernetes. I have created a jar file and I need to start the jar file when kube creates the pod. I want to pass args from kube pod.yml to call a java class in the jar file packaged in the docker image -
Dockerfile
==========
FROM openjdk:8
ARG JAR_FILE=target/app.jar
# cd /usr/local/runme
WORKDIR /usr/local/runme/
COPY ${JAR_FILE} app-jar-with-dependencies.jar
The following is my pod file -
apiVersion: v1
kind: Pod
metadata:
name: app
labels:
zone: dev
version: v1
spec:
containers:
- name: app-ctr
image: "docker-image-created-from-above-dockerfile"
ports:
- containerPort: 8080
env:
- name: NO_OF_CONSUMERS
value: "1"
args: [ "-n", "$(NO_OF_CONSUMERS)"]
In my pom.xml I have the following mainClass -
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>com.app.KafkaConsumer</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id> <!-- this is used for inheritance merges -->
<phase>package</phase> <!-- bind to the packaging phase -->
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
I am not sure how to go about this. Do I need to use ENTRYPOINT or CMD or anything else.
You need to have an entrypoint in the Dockerfile which starts the applicaion/process like java -jar app-jar-with-dependencies.jar. Then in the pod definition when args is used kubernetes will pass them as a run time args.