Pre-install Jenkins plugins using Docker image
This seems to be the right idea: https://stackoverflow.com/questions/29328278/installing-jenkins-plugins-to-docker-jenkins/29328489#29328489

so in the Dockerfile you'd just use:

COPY plugins.txt /usr/share/jenkins/plugins.txt
RUN /usr/local/bin/install-plugins.sh &lt; /usr/share/jenkins/plugins.txt


I tried it and it worked for me.