Build history and logs in Jenkins - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Jenkins Build History Command Output

What is the output of the following Jenkins CLI command when run on a job with 3 completed builds?

Jenkins

java -jar jenkins-cli.jar -s http://localhost:8080/ list-builds my-job

A

Build #3 SUCCESS
Build #2 FAILURE
Build #1 SUCCESS

B

Build #1 SUCCESS
Build #2 FAILURE
Build #3 SUCCESS

C No builds found

D Error: Job 'my-job' not found

💡 Hint

Jenkins CLI lists builds in descending order by default.

The 'list-builds' command shows builds from newest to oldest. So build #3 is listed first.

❓ Troubleshoot

intermediate

Troubleshooting Missing Build Logs

A Jenkins user reports that build logs for a specific job are missing from the Jenkins UI. Which of the following is the most likely cause?

A The Jenkins master has run out of disk space and deleted old logs

B The job was never executed

C The Jenkins agent is offline

D The build was triggered manually

💡 Hint

Jenkins may delete old logs automatically when disk space is low.

When disk space is low, Jenkins may clean up old build logs to free space, causing them to disappear from the UI.

❓ Configuration

advanced

Configuring Build Log Retention

Which configuration snippet in a Jenkins Pipeline script correctly sets the build log retention to keep logs for 10 days and a maximum of 5 builds?

Jenkins

pipeline {
  agent any
  options {
    // Your configuration here
  }
  stages {
    stage('Build') {
      steps {
        echo 'Building...'
      }
    }
  }
}

A discardOldBuilds(days: 10, maxBuilds: 5)

B buildDiscarder(logRotator(daysToKeepStr: '10', numToKeepStr: '5'))

C logRetention(days: 10, builds: 5)

D keepBuilds(daysToKeep: 10, maxBuildsToKeep: 5)

💡 Hint

Use the 'buildDiscarder' option with 'logRotator' in declarative pipelines.

The 'buildDiscarder' with 'logRotator' is the correct syntax to configure log retention in Jenkins pipelines.

🔀 Workflow

advanced

Accessing Build Logs via REST API

Which HTTP request correctly retrieves the console log of build number 15 for a Jenkins job named 'deploy-app'?

A GET http://jenkins-server/api/json/job/deploy-app/build/15/log

B POST http://jenkins-server/job/deploy-app/builds/15/log

C GET http://jenkins-server/job/deploy-app/15/consoleText

D GET http://jenkins-server/job/deploy-app/console/15

💡 Hint

Jenkins exposes console logs at the 'consoleText' endpoint for a build.

The console log for a specific build is accessed via the URL ending with '//consoleText'.

✅ Best Practice

expert

Best Practice for Managing Jenkins Build Logs in Large Environments

In a large Jenkins environment with many jobs and builds, what is the best practice to efficiently manage build history and logs?

A Disable build logs to save disk space and rely on external monitoring tools

B Keep all build logs indefinitely on the Jenkins master to ensure full history

C Manually delete old build logs weekly to free up space

D Configure build discarders to limit log retention and archive important artifacts externally

💡 Hint

Automate log retention and use external storage for important data.

Automatically discarding old logs and archiving important artifacts externally prevents disk space issues and keeps Jenkins responsive.