Artifact retention policies in Jenkins - Mini Project: Build & Apply

Artifact retention policies

📖 Scenario: You are managing a Jenkins pipeline that builds software projects. Each build produces artifacts like compiled files or reports. To save disk space, you want to keep only a limited number of recent artifacts and discard older ones automatically.

🎯 Goal: Set up a Jenkins pipeline script that defines artifact retention policies to keep only the last 3 builds' artifacts and discard older ones.

📋 What You'll Learn

Create a Jenkins pipeline script with a pipeline block

Add a post section with always condition

Use archiveArtifacts to save build artifacts

Use buildDiscarder with logRotator to keep only last 3 builds

💡 Why This Matters

🌍 Real World

In real projects, managing disk space by cleaning old build artifacts is important to keep Jenkins servers healthy and fast.

💼 Career

Understanding artifact retention policies is essential for DevOps engineers to maintain CI/CD pipelines efficiently.

1

Create basic Jenkins pipeline

Create a Jenkins pipeline script with a pipeline block and a stages section containing one stage named Build. Inside the stage, add a steps block with a shell command echo "Building project".

Jenkins

pipeline {
    agent any
    stages {
        stage('Build') {
            steps {
                // Your code here
            }
        }
    }
}

Hint

Use pipeline and stage blocks. Use sh to run shell commands.

2

Add artifact archiving step

Inside the Build stage's steps block, add an archiveArtifacts step to archive all files matching **/*.jar.

Jenkins

pipeline {
    agent any
    stages {
        stage('Build') {
            steps {
                sh 'echo "Building project"'
                // Your code here
            }
        }
    }
}

Hint

Use archiveArtifacts with the artifacts parameter set to '**/*.jar'.

3

Add artifact retention policy

Add a options block inside the pipeline block. Inside options, add a buildDiscarder with a logRotator that keeps only the last 3 builds by setting numToKeepStr: '3'.

Jenkins

pipeline {
    agent any
    options {
        // Your code here
    }
    stages {
        stage('Build') {
            steps {
                sh 'echo "Building project"'
                archiveArtifacts artifacts: '**/*.jar'
            }
        }
    }
}

Hint

Use options block with buildDiscarder(logRotator(numToKeepStr: '3')).

4

Print confirmation message

Add a post section inside the pipeline block with an always condition. Inside always, add a script block that prints "Artifact retention policy applied" using echo.

Jenkins

pipeline {
    agent any
    options {
        buildDiscarder(logRotator(numToKeepStr: '3'))
    }
    stages {
        stage('Build') {
            steps {
                sh 'echo "Building project"'
                archiveArtifacts artifacts: '**/*.jar'
            }
        }
    }
    // Your code here
}

Hint

Use post { always { script { echo 'Artifact retention policy applied' } } } inside the pipeline.

Practice

1. What is the main purpose of artifact retention policies in Jenkins?

easy

A. To manage disk space by deleting old build files

B. To speed up the build process by caching dependencies

C. To increase the number of builds stored indefinitely

D. To automatically trigger builds on code changes

Solution

1. Step 1: Understand artifact retention policies

   Artifact retention policies control how long build files are kept to avoid using too much disk space.

2. Step 2: Identify the main goal

   The main goal is to delete old build files to free up disk space.

3. Final Answer:

   To manage disk space by deleting old build files -> Option A

4. Quick Check:

   Artifact retention = disk space management [OK]

Hint: Retention policies delete old builds to save space [OK]

Common Mistakes:

• Confusing retention with build triggering
• Thinking retention speeds up builds
• Assuming retention keeps all builds forever

2. Which Jenkins pipeline syntax correctly sets a retention policy to keep only the last 5 builds?

easy

A. archiveArtifacts(numToKeepStr: '5')

B. buildDiscarder(keepLast: 5)

C. buildDiscarder(logRotator(numToKeepStr: '5'))

D. archiveArtifacts(logRotator(numToKeepStr: '5'))

Solution

1. Step 1: Identify correct syntax for retention

   Retention uses buildDiscarder with logRotator to specify how many builds to keep.

2. Step 2: Check option correctness

   buildDiscarder(logRotator(numToKeepStr: '5')) uses correct syntax: buildDiscarder(logRotator(numToKeepStr: '5')). Others misuse archiveArtifacts or wrong parameters.

3. Final Answer:

   buildDiscarder(logRotator(numToKeepStr: '5')) -> Option C

4. Quick Check:

   Retention uses buildDiscarder + logRotator [OK]

Hint: Retention = buildDiscarder with logRotator [OK]

Common Mistakes:

• Using archiveArtifacts to set retention
• Wrong parameter names like keepLast
• Nesting logRotator inside archiveArtifacts

3. Given this Jenkins pipeline snippet:

pipeline {
  options {
    buildDiscarder(logRotator(numToKeepStr: '3', daysToKeepStr: '7'))
  }
  stages {
    stage('Build') {
      steps {
        echo 'Building...'
      }
    }
  }
}

What happens to builds older than 7 days or beyond the last 3 builds?

medium

A. They are deleted to free disk space

B. They are archived permanently

C. They trigger a new build automatically

D. They are kept indefinitely

Solution

1. Step 1: Understand logRotator parameters

   It keeps only the last 3 builds and deletes builds older than 7 days.

2. Step 2: Determine effect on old builds

   Builds older than 7 days or beyond the last 3 are deleted to save space.

3. Final Answer:

   They are deleted to free disk space -> Option A

4. Quick Check:

   logRotator deletes old builds [OK]

Hint: logRotator deletes builds older than days or count [OK]

Common Mistakes:

• Thinking builds are archived permanently
• Assuming builds trigger new builds
• Believing builds are kept forever

4. You wrote this Jenkins pipeline snippet to keep artifacts for 10 days:

options {
  buildDiscarder(logRotator(artifactDaysToKeep: '10'))
}

But artifacts are not deleted after 10 days. What is the likely problem?

medium

A. logRotator does not support artifact retention

B. The buildDiscarder option must be inside stages

C. You must use archiveArtifacts to delete old artifacts

D. The parameter name should be artifactDaysToKeepStr, not artifactDaysToKeep

Solution

1. Step 1: Check logRotator parameter names

   logRotator parameters for strings end with 'Str', like artifactDaysToKeepStr.

2. Step 2: Identify the syntax issue

   Missing 'Str' means the parameter is not recognized, so default retention applies and artifacts aren't deleted after 10 days.

3. Final Answer:

   The parameter name should be artifactDaysToKeepStr, not artifactDaysToKeep -> Option D

4. Quick Check:

   logRotator params end with 'Str' [OK]

Hint: logRotator params like artifactDaysToKeepStr end with Str [OK]

Common Mistakes:

• Using wrong parameter names
• Expecting logRotator to delete artifacts
• Placing buildDiscarder outside options block

5. You want to keep artifacts only for the last 4 builds and delete older artifacts automatically, while keeping older builds. Which Jenkins pipeline snippet correctly applies this retention policy?

hard

A. steps { archiveArtifacts artifacts: '**/*', onlyIfSuccessful: true, retentionDays: 4 }

B. options { buildDiscarder(logRotator(artifactNumToKeepStr: '4')) }

C. options { buildDiscarder(logRotator(numToKeepStr: '4')) } steps { archiveArtifacts artifacts: '**/*', onlyIfSuccessful: true }

D. steps { archiveArtifacts artifacts: '**/*', keepOnlyLast: 4 }

Solution

1. Step 1: Understand roles for artifact-specific retention

   To keep artifacts from only the last 4 builds while retaining builds, use artifactNumToKeepStr.

2. Step 2: Check option correctness

   options { buildDiscarder(logRotator(artifactNumToKeepStr: '4')) }: buildDiscarder(logRotator(artifactNumToKeepStr: '4')) keeps artifacts from last 4 builds, deletes older artifacts, keeps all builds. C deletes old builds too. B/D use invalid params.

3. Final Answer:

   options { buildDiscarder(logRotator(artifactNumToKeepStr: '4')) } -> Option B

4. Quick Check:

   artifactNumToKeepStr for artifacts only [OK]

Hint: artifactNumToKeepStr keeps artifacts from last N builds [OK]

Common Mistakes:

• Using invalid parameters like retentionDays or keepOnlyLast
• Trying to control retention only via archiveArtifacts
• Misplacing buildDiscarder outside options block