System configuration management in Jenkins - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Jenkins CLI: List all installed plugins

What is the output of the following Jenkins CLI command when run on a Jenkins server with plugins installed?

Jenkins

java -jar jenkins-cli.jar -s http://localhost:8080/ list-plugins

A Lists all plugins with their versions and enabled/disabled status

B Shows an error: 'list-plugins' is not a valid command

C Outputs only the names of plugins without versions

D Returns an empty list even if plugins are installed

💡 Hint

Think about what the 'list-plugins' command is designed to show in Jenkins CLI.

The 'list-plugins' command in Jenkins CLI lists all installed plugins along with their versions and whether they are enabled or disabled.

❓ Configuration

intermediate

Jenkins Pipeline: Correct syntax for environment variables

Which Jenkins Pipeline snippet correctly sets environment variables for use in the pipeline?

Jenkins

pipeline {
  agent any
  environment {
    VAR1 = 'value1'
    VAR2 = 'value2'
  }
  stages {
    stage('Example') {
      steps {
        echo "VAR1 is ${VAR1} and VAR2 is ${VAR2}"
      }
    }
  }
}

A

environment {
  VAR1 => 'value1'
  VAR2 => 'value2'
}

B

environment {
  VAR1: 'value1'
  VAR2: 'value2'
}

C

environment {
  'VAR1' = 'value1'
  'VAR2' = 'value2'
}

D

environment {
  VAR1 = 'value1'
  VAR2 = 'value2'
}

💡 Hint

Look at the correct syntax for environment variables in Jenkins declarative pipeline.

In Jenkins declarative pipeline, environment variables are set using VAR = 'value' syntax inside the environment block.

🔀 Workflow

advanced

Jenkins Job DSL: Creating a freestyle job with parameters

Which Job DSL script correctly creates a freestyle Jenkins job named 'BuildApp' with a string parameter 'BRANCH' defaulting to 'main'?

A

job('BuildApp') {
  parameters {
    stringParameter('BRANCH', 'main', 'Git branch to build')
  }
}

B

job('BuildApp') {
  parameters {
    string('BRANCH', 'main', 'Git branch to build')
  }
}

C

job('BuildApp') {
  parameters {
    stringParam('BRANCH', 'main', 'Git branch to build')
  }
}

D

job('BuildApp') {
  parameters {
    paramString('BRANCH', 'main', 'Git branch to build')
  }
}

💡 Hint

Check the exact method name for string parameters in Jenkins Job DSL.

The correct method to define a string parameter in Job DSL is stringParam(name, defaultValue, description).

❓ Troubleshoot

advanced

Jenkins Pipeline: Diagnosing a syntax error in a scripted pipeline

Given this Jenkins scripted pipeline snippet, what error will Jenkins report?

Jenkins

node {
  stage('Build') {
    echo 'Building...'
  }
  stage('Test')
    echo 'Testing...'
  }
}

A No error, pipeline runs successfully

B SyntaxError: expecting '{' after stage declaration

C RuntimeException: stage 'Test' not found

D GroovyCastException: Cannot cast String to Closure

💡 Hint

Look carefully at the braces and structure after the 'stage('Test')' line.

The 'stage' block must have braces enclosing its steps. Missing '{' causes a syntax error.

✅ Best Practice

expert

Jenkins Configuration as Code (JCasC): Correct YAML snippet for global security

Which YAML snippet correctly disables Jenkins security using Configuration as Code (JCasC)?

A

jenkins:
  securityRealm:
    none: {}
  authorizationStrategy:
    anyoneCanDoAnything: {}

B

jenkins:
  securityRealm:
    local:
      allowsSignup: true
      users: []
  authorizationStrategy:
    anyoneCanDoAnything: false

C

jenkins:
  securityRealm:
    local:
      allowsSignup: false
      users: []
  authorizationStrategy:
    loggedInUsersCanDoAnything: false

D

jenkins:
  securityRealm:
    none: {}
  authorizationStrategy:
    loggedInUsersCanDoAnything: true

💡 Hint

Disabling security means no authentication required and full access for anyone including anonymous users.

Setting securityRealm to 'none' disables authentication. The 'anyoneCanDoAnything' authorizationStrategy allows full access without restrictions.