I have a weird problem with Docker and hope someone here can help me :)
I want to create a keycloak image that is derived from the image jboss/keycloak. The idea is that in the Dockerfile also a preconfigured standalone.xml is copied into the image and keycloak can start directly without manual work.
But as soon as I write for example a
"CMD touch /opt/test.txt"
into the file the container crashes with the message "12:02:14,290 INFO [org.jboss.modules] (main) JBoss Modules version 1.9.1.Final WFLYSRV0073: Invalid option '/bin/sh'"
This is just a new file with no purpose, the changes to the .xml are not in there yet.
As soon as I put only the FROM back in and rebuild everything works again.
I thought through the layers in the container you could mod an image, but here it doesn't seem to work. Can someone tell me why ?
So far it has always worked with the alpine image, but I don't want to build the whole keycloak setup again myself, when there is already an official image for it.
This is basically what I had in mind:
FROM jboss/keycloak:X.XX
CMD rm /opt/jboss/keycloak/standalone/configuration/standalone.xml
COPY ./keycloak/standalone.xml /opt/jboss/keycloak/standalone/configuration/
Thanks for help :)
Change
CMD rm
to
RUN rm
RUN is part of building. every RUN command is executed while your image is built.
With CMD you define (or override) the default command when running/starting a container based on your image (and you don't want to change keycloaks default CMD)