Docker-in-Docker considerations in Jenkins - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to run Docker inside a Jenkins pipeline using Docker-in-Docker.

Jenkins

pipeline {
  agent {
    docker {
      image '[1]'
      args '--privileged'
    }
  }
  stages {
    stage('Build') {
      steps {
        sh 'docker info'
      }
    }
  }
}

Drag options to blanks, or click blank then click option'

Aalpine:3.12

Bubuntu:latest

Cdocker:dind

Dnode:14

Attempts:

3 left

💡 Hint

Common Mistakes

Using a base image without Docker installed like ubuntu or alpine.

Forgetting to add the --privileged flag.

The docker:dind image includes the Docker daemon needed for Docker-in-Docker.

2fill in blank

medium

Complete the Jenkins pipeline step to start the Docker daemon inside the container.

Jenkins

steps {
  sh '[1] -b tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock &'
}

Drag options to blanks, or click blank then click option'

Adockerd

Bdocker

Cdocker-compose

Dservice docker start

Attempts:

3 left

💡 Hint

Common Mistakes

Using docker instead of dockerd.

Trying to start Docker with service commands inside the container.

dockerd is the Docker daemon command that starts the Docker service inside the container.

3fill in blank

hard

Fix the error in the Docker-in-Docker Jenkins pipeline by completing the missing argument to allow privileged mode.

Jenkins

agent {
  docker {
    image 'docker:dind'
    args '[1]'
  }
}

Drag options to blanks, or click blank then click option'

A-v /var/run/docker.sock:/var/run/docker.sock

B--network host

C--rm

D--privileged

Attempts:

3 left

💡 Hint

Common Mistakes

Using volume mount flags instead of privileged mode.

Forgetting to add any arguments.

The --privileged flag is required to allow Docker-in-Docker to run properly with full permissions.

4fill in blank

hard

Fill both blanks to correctly mount the Docker socket and set environment variable for Docker-in-Docker.

Jenkins

agent {
  docker {
    image 'docker:dind'
    args '[1] [2]'
  }
}

Drag options to blanks, or click blank then click option'

A-v /var/run/docker.sock:/var/run/docker.sock

B-e DOCKER_HOST=unix:///var/run/docker.sock

C--privileged

D-p 2375:2375

Attempts:

3 left

💡 Hint

Common Mistakes

Using privileged flag instead of mounting the socket.

Not setting the DOCKER_HOST environment variable.

Mounting the Docker socket allows the container to communicate with the host Docker daemon. Setting DOCKER_HOST points Docker commands to the correct daemon.

5fill in blank

hard

Fill all three blanks to create a Jenkins pipeline step that builds a Docker image, tags it, and pushes it to a registry.

Jenkins

steps {
  sh 'docker build -t [1] .'
  sh 'docker tag [2] myregistry.com/myimage:latest'
  sh 'docker push [3]'
}

Drag options to blanks, or click blank then click option'

Amyimage:latest

Cmyregistry.com/myimage:latest

Dmyimage

Attempts:

3 left

💡 Hint

Common Mistakes

Using the full registry path in the build command.

Tagging with the wrong image name.

Pushing the wrong image tag.

The build tags the image as myimage. Then it is tagged with the full registry path before pushing.