container not starting after volume mount in docker compose - docker

Question

I have 4 services to run through docker compose:
version: "3"
services:
billingmock:
build:
context: ./mock/soap/billing
dockerfile: ./Dockerfile
ports:
- 8096:8096
salcusmock:
build:
context: ./mock/soap/salcus
dockerfile: ./Dockerfile
ports:
- 8088:8088
ngocsrestmock:
build:
context: ./mock/rest/ngocs-rest
dockerfile: ./Dockerfile
volumes:
- /test/mock-data/Ngocs-Rest-Mock:/usr/src/ngocs-rest-mock/
ports:
- 8091:8091
kafka:
image: <some-repo>.com/mce/kafka_local_r20-11
ports:
- 9092:9092
- 8080:8080
- 8081:8081
- 8082:8082
but ngocs container is not running, all other container s are running when i check the log of that container i get : Exited (1) 36 seconds ago
Error: Unable to access jarfile mocks-mock-ngocs-rest-executable-1.0.0-SNAPSHOT.jar
dockerfile for that service is :
FROM openjdk:8
COPY /executable/target/mocks-mock-ngocs-rest-executable-1.0.0-SNAPSHOT.jar /usr/src/ngocs-rest-mock/
WORKDIR /usr/src/ngocs-rest-mock/
ENTRYPOINT ["java","-jar","mocks-mock-ngocs-rest-executable-1.0.0-SNAPSHOT.jar"]
i have to start the container manually and then it runs but volume is not mounted. What seems to be the issue ??? Also if i remove the volume section in docker compose then it runs.

Answer 1

If you have volumes: that binds a host directory to a container directory, at container startup time, the contents of that host directory always completely hide anything that was in the underlying image. In your case, you're mounting a directory over the directory that contains the jar file, so the actual application gets hidden.
You should restructure your application to keep the data somewhere separate from the application code. Using simple top-level directories like /app and /data is common enough, or you can make the data directory a subdirectory of your application directory.
Once you've done this, you can change the volumes: mount to a different directory:
# for example, a "data" subdirectory of the application directory
volumes:
- /test/mock-data/Ngocs-Rest-Mock:/usr/src/ngocs-rest-mock/data