Docker not found when building docker image using Docker Jenkins container pipeline

dockerdockerfileJenkinsjenkins-pipeline

I have a Jenkins running as a docker container, now I want to build a Docker image using pipeline, but Jenkins container always tells Docker not found.

[simple-tdd-pipeline] Running shell script
+ docker build -t simple-tdd .
/var/jenkins_home/workspace/simple-tdd-pipeline@tmp/durable-
ebc35179/script.sh: 2: /var/jenkins_home/workspace/simple-tdd-
pipeline@tmp/durable-ebc35179/script.sh: docker: not found

Here is how I run my Jenkins image:

docker run --name myjenkins -p 8080:8080 -p 50000:50000 -v 
/var/jenkins_home -v /var/run/docker.sock:/var/run/docker.sock 
jenkins

And the DockerFile of Jenkins image is:
https://github.com/jenkinsci/docker/blob/9f29488b77c2005bbbc5c936d47e697689f8ef6e/Dockerfile

Best Answer

You're missing the docker client. Install it as this in Dockerfile:

RUN curl -fsSLO https://get.docker.com/builds/Linux/x86_64/docker-17.04.0-ce.tgz \
  && tar xzvf docker-17.04.0-ce.tgz \
  && mv docker/docker /usr/local/bin \
  && rm -r docker docker-17.04.0-ce.tgz

Source

Related Solutions

Docker – the difference between a Docker image and a container

An instance of an image is called a container. You have an image, which is a set of layers as you describe. If you start this image, you have a running container of this image. You can have many running containers of the same image.

You can see all your images with docker images whereas you can see your running containers with docker ps (and you can see all containers with docker ps -a).

So a running instance of an image is a container.

Linux – How to add users to Docker container

The trick is to use useradd instead of its interactive wrapper adduser. I usually create users with:

RUN useradd -ms /bin/bash newuser

which creates a home directory for the user and ensures that bash is the default shell.

You can then add:

USER newuser
WORKDIR /home/newuser

to your dockerfile. Every command afterwards as well as interactive sessions will be executed as user newuser:

docker run -t -i image
newuser@131b7ad86360:~$

You might have to give newuser the permissions to execute the programs you intend to run before invoking the user command.

Using non-privileged users inside containers is a good idea for security reasons. It also has a few drawbacks. Most importantly, people deriving images from your image will have to switch back to root before they can execute commands with superuser privileges.

Best Answer

Related Solutions

Docker – the difference between a Docker image and a container

Linux – How to add users to Docker container

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