How to create a Jenkins pipeline that builds a Docker image - docker

Question

I'm new to Docker and Jenkins and I'm trying to create a Jenkins Pipeline that builds a Docker image.
I'm stuck when trying to build and keep receiving this error:
/var/jenkins_home/workspace/Docker-Pipeline#tmp/durable-a11b32f8/script.sh: line 1: docker: command not found
I've installed ubuntu on a VM.
Installed docker.
Installed jenkins/jenkins from dockerhub.
I followed this tutorial for the rest:
https://www.youtube.com/watch?v=z32yzy4TrKM&t=147s
I'm doing the exact same thing as him but it keeps failing.
Started by user admin
Obtained Jenkinsfile from git https://github.com/naorca/NodeApp.git
Running in Durability level: MAX_SURVIVABILITY
[Pipeline] Start o
f Pipeline
[Pipeline] node
Running on Jenkins in /var/jenkins_home/workspace/Docker-Pipeline
[Pipeline] {
[Pipeline] stage
[Pipeline] { (Clone repository)
[Pipeline] checkout
No credentials specified
> git rev-parse --is-inside-work-tree # timeout=10
Fetching changes from the remote Git repository
> git config remote.origin.url https://github.com/naorca/NodeApp.git # timeout=10
Fetching upstream changes from https://github.com/naorca/NodeApp.git
> git --version # timeout=10
> git fetch --tags --progress https://github.com/naorca/NodeApp.git +refs/heads/*:refs/remotes/origin/*
> git rev-parse refs/remotes/origin/master^{commit} # timeout=10
> git rev-parse refs/remotes/origin/origin/master^{commit} # timeout=10
Checking out Revision b74538f2f34b6c28306fcca8119e215b87124e5e (refs/remotes/origin/master)
> git config core.sparsecheckout # timeout=10
> git checkout -f b74538f2f34b6c28306fcca8119e215b87124e5e
Commit message: "Update Jenkinsfile"
> git rev-list --no-walk b74538f2f34b6c28306fcca8119e215b87124e5e # timeout=10
[Pipeline] }
[Pipeline] // stage
[Pipeline] stage
[Pipeline] { (Build image)
[Pipeline] sh
+ docker build -t naorca/nodeapp .
/var/jenkins_home/workspace/Docker-Pipeline#tmp/durable-a11b32f8/script.sh: line 1: docker: command not found
[Pipeline] }
[Pipeline] // stage
[Pipeline] }
[Pipeline] // node
[Pipeline] End of Pipeline
ERROR: script returned exit code 127
Finished: FAILURE

Answer 1

TL;DR: You must have Docker within your Jenkins Agent.
Following the process you described above, I got Jenkins up and running using the latest jenkins/jenkins image from Docker Hub. After looking over the container's file system, I confirmed what I had speculated about in my comment on your question: Docker is not installed within the Jenkins container. Assuming you are using the Jenkins Master server as your Agent for the pipeline job, you have a couple options that come to mind:
Extend the existing docker container -- using something like FROM jenkins/jenkins inside of a new docker file -- to include your dependencies.
Bind your existing docker daemon from the host into the run-time of the Jenkins container.
While I am partial to the first solution, I found an implementation of the second solution on the Docker Forums: "Using docker in a dockerized Jenkins container" I then gave that solution a try and can confirm that Docker is present for me in the Jenkins Master container after launching the Jenkins container with the following command:
docker run -v /var/run/docker.sock:/var/run/docker.sock \
-v $(which docker):$(which docker) \
-p 8000:8080 \
-p 50000:50000 \
jenkins/jenkins
I am not sure, but I would imagine there could be some negative security implications for the host of the Jenkins Master due to mounting its own Docker socket and Docker executable into the container; however, I would leave that up to someone more knowledgeable about Docker's internals to determine. Regardless, I can confirm that the solution above does work.