Using Jekyll docker inside Jenkins - docker

Question

I'm trying to build a jekyll website via my Jenkins server (which runs inside a container) and I have a stage in my Jenkinsfile that looks like this:
stage('Building Website') {
agent {
docker {
image 'jekyll/jekyll:builder'
}
}
steps {
sh 'jekyll --version'
}
}
The very first time I run my job it pulls the jekyll docker image and runs fine (although it does fetch a bunch of gems before running jekyll which doesn't happen when I run the docker manually outside jenkins) but then the next jobs fail giving this error:
jekyll --version
/usr/jekyll/bin/jekyll: exec: line 15: /usr/local/bundle/bin/jekyll: not found
Any ideas what I'm doing wrong here?

Answer 1

As you can see in the jenkins log file, jenkins runs docker with the -u 1000:1000 argument, since this user does not exits in the jekyll/jekyll image, the command fails with the error .../bin/jekyll: not found
Here is a sample Jenkinsfile:
pipeline {
agent
{
docker
{
image 'jekyll/jekyll:3.8'
args '''
-u root:root
-v "${WORKSPACE}:/srv/jekyll"
'''
}
}
stages {
stage('Test') {
steps {
sh '''
cd /srv/jekyll
jekyll --version
'''
}
}
}
}

Answer 2

To add to the other answer, note the containerized Jenkins doesn't not contain the docker binary, so docker commands will still fail.
A few solutions
Make a dockerfile that inherits from the jenkins image and installs docker as well, creating a new image.
Manually install docker inside of the container. This will work until you pull a new image, and you'll have to do it over again.
Open an interactive terminal into the jenkins container
docker container exec -it -u root <container id> bash
Then install docker
curl https://get.docker.com/ > dockerinstall && chmod 777 dockerinstall && ./dockerinstall
Exit the container and set perms on docker.sock
sudo chmod 666 /var/run/docker.sock
Finished!