Docker container is running without port mapping - docker

Question

I created a docker-compose file to build image from dockerfile and then run container this is my code:
Dockerfile
FROM anapsix/alpine-java
VOLUME [ "/var/run/jars/" ]
ADD hello-world.jar /var/run/jars/
EXPOSE 8080
ENTRYPOINT [ "java" ]
CMD ["-?"]
docker-compose.yml
version: '3'
services:
hello-world-image:
build: .
image: hello-world-image
hello-world:
image: hello-world-image
container_name: hello-world
ports:
- "8080:8080"
volumes:
- ./logs_ACM:/root/logs_ACM
command: -jar /var/run/jars/hello-world.jar
restart: always
docker ps output:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
103b0a3c30e3 hello-world-image "java -jar /var/run/…" 5 seconds ago Restarting (1) Less than a second ago hello-world
When i check running containers with "docker ps" the port column is empty therefore no port mapping was done even though i specified ports in my docker compose file.
What changes needed to be done on my docker-compose file to solve this issue ?
new version of dockerfile and docker-compose :
FROM anapsix/alpine-java
USER root
RUN mkdir -p /var/run/jars/
COPY spring-petclinic-2.4.2.jar /var/run/jars/
EXPOSE 8081
ENTRYPOINT [ "java" ]
CMD ["-?"]
version: '3' # '3' means '3.0'
services:
spring-petclinic:
build: .
# Only if you're planning to `docker-compose push`
# image: registry.example.com/name/hello-world-image:${TAG:-latest}
ports:
- "8081:8081"
volumes:
# A bind-mount directory to read out log files is a good use of
# `volumes:`. This does not require special setup in the Dockerfile.
- ./logs_ACM:/root/logs_ACM
command: -jar /var/run/jars/spring-petclinic-2.4.2.jar
mysql:
image: mysql:5.7
ports:
- "3306:3306"
environment:
- MYSQL_ROOT_PASSWORD=
- MYSQL_ALLOW_EMPTY_PASSWORD=true
- MYSQL_USER=petclinic
- MYSQL_PASSWORD=petclinic
- MYSQL_DATABASE=petclinic
volumes:
- "./conf.d:/etc/mysql/conf.d:ro"

Answer 1

I think your single biggest problem here is the VOLUME directive in the Dockerfile. The Dockerfile documentation for VOLUME notes:
Changing the volume from within the Dockerfile: If any build steps change the data within the volume after it has been declared, those changes will be discarded.
So when you declare a VOLUME for the directory containing the jar file, and then try to ADD content to it, it gets lost.
In most practical cases you don't need a VOLUME. You should be able to rewrite the Dockerfile to:
FROM anapsix/alpine-java
# Do not create a VOLUME.
# Generally prefer COPY to ADD. Will create the target directory if needed.
COPY hello-world.jar /var/run/jars/
EXPOSE 8080
# Don't set an ENTRYPOINT just naming an interpreter.
# Do make the default container command be to run the application.
CMD ["java", "-jar", "/var/run/jars/hello-world.jar"]
In the docker-compose.yml file, you don't need a separate "service" just to build the image, and you shouldn't typically need to override container_name: (provided by Compose) or command: (from the Dockerfile). This could be reduced to:
version: '3.8' # '3' means '3.0'
services:
hello-world:
build: .
# Only if you're planning to `docker-compose push`
# image: registry.example.com/name/hello-world-image:${TAG:-latest}
ports:
- "8080:8080"
volumes:
# A bind-mount directory to read out log files is a good use of
# `volumes:`. This does not require special setup in the Dockerfile.
- ./logs_ACM:/root/logs_ACM
# Don't enable auto-restart until you've debugged the start sequence
# restart: always