CI/CD tools landscape in Jenkins - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does CI/CD stand for in software development?

CI/CD stands for Continuous Integration and Continuous Delivery (or Continuous Deployment). It is a method to frequently deliver apps to customers by introducing automation into the stages of app development.

beginner

Name three popular CI/CD tools used in the industry.

Popular CI/CD tools include Jenkins, GitLab CI, and CircleCI. Each helps automate building, testing, and deploying software.

beginner

What is Jenkins and why is it widely used?

Jenkins is an open-source automation server that helps automate parts of software development related to building, testing, and deploying. It is popular because it is free, highly customizable, and supports many plugins.

intermediate

How does Continuous Integration improve software quality?

Continuous Integration encourages developers to merge code changes frequently. Automated tests run on each merge, catching bugs early and reducing integration problems.

intermediate

What is the difference between Continuous Delivery and Continuous Deployment?

Continuous Delivery means code changes are automatically prepared for release but require manual approval to deploy. Continuous Deployment automatically releases every change that passes tests to production without manual steps.

Which tool is an open-source automation server commonly used for CI/CD?

A Jenkins

B Photoshop

C Slack

D Excel

Jenkins is a popular open-source automation server used to build, test, and deploy software.

What is the main goal of Continuous Integration?

A Deploy code manually

B Merge code frequently and run automated tests

C Write documentation

D Design user interfaces

Continuous Integration focuses on merging code often and running tests automatically to catch issues early.

Which of the following is NOT a CI/CD tool?

A Microsoft Word

B GitLab CI

C Jenkins

D CircleCI

Microsoft Word is a word processor, not a CI/CD tool.

What does Continuous Delivery require before deploying to production?

A Automatic deployment

B No testing

C Manual approval

D Writing code

Continuous Delivery prepares code for release but requires manual approval before deployment.

Why are plugins important in Jenkins?

A They delete code

B They slow down the server

C They change the user interface color

D They add extra features and integrations

Plugins extend Jenkins capabilities by adding new features and integrations with other tools.

Explain the basic workflow of a CI/CD pipeline using Jenkins.

Think about what happens from code change to deployment.

List and describe the main benefits of using CI/CD tools in software development.

Consider how automation helps developers and teams.

Practice

1. What is the main purpose of CI/CD tools like Jenkins in software development?

easy

A. To design user interfaces

B. To write code manually

C. To automate building, testing, and deploying software

D. To manage hardware resources

Solution

1. Step 1: Understand CI/CD tools role

   CI/CD tools automate repetitive tasks in software development like building, testing, and deploying.

2. Step 2: Compare options

   Options B, C, and D describe unrelated tasks. Only To automate building, testing, and deploying software matches the automation purpose.

3. Final Answer:

   To automate building, testing, and deploying software -> Option C

4. Quick Check:

   CI/CD tools automate software delivery = A [OK]

Hint: CI/CD tools automate software delivery steps [OK]

Common Mistakes:

• Confusing CI/CD tools with coding or design tools
• Thinking CI/CD tools manage hardware
• Assuming CI/CD tools replace developers

2. Which of the following is the correct way to define a stage in a Jenkins pipeline?

easy

A. stage('Build') { steps { echo 'Building...' } }

B. step('Build') { echo 'Building...' }

C. stage: Build { echo 'Building...' }

D. buildStage { echo 'Building...' }

Solution

1. Step 1: Recall Jenkins pipeline syntax

   Jenkins uses stage('name') { steps { ... } } to define stages.

2. Step 2: Check options for correct syntax

   Only stage('Build') { steps { echo 'Building...' } } matches the correct syntax with stage and steps blocks.

3. Final Answer:

   <code>stage('Build') { steps { echo 'Building...' } }</code> -> Option A

4. Quick Check:

   Correct Jenkins stage syntax = C [OK]

Hint: Stages use stage('name') with steps block [OK]

Common Mistakes:

• Using 'step' instead of 'stage'
• Missing the steps block inside stage
• Incorrect block syntax with colons or missing braces

3. Given this Jenkins pipeline snippet, what will be printed during the 'Test' stage?

pipeline {
  agent any
  stages {
    stage('Build') {
      steps { echo 'Building...' }
    }
    stage('Test') {
      steps { echo 'Testing...' }
    }
  }
}

medium

A. Testing... Building...

B. Testing...

C. Building...

D. Building... Testing...

Solution

1. Step 1: Understand pipeline stage order

   The pipeline runs stages in order: 'Build' then 'Test'.

2. Step 2: Identify echo outputs

   'Build' stage prints 'Building...', 'Test' stage prints 'Testing...'. Both run sequentially.

3. Final Answer:

   Building... Testing... -> Option D

4. Quick Check:

   Stages run in order, print messages in sequence = B [OK]

Hint: Stages run sequentially, outputs print in order [OK]

Common Mistakes:

• Assuming stages run in parallel by default
• Mixing output order
• Ignoring all stages run unless skipped

4. Identify the error in this Jenkins pipeline snippet:

pipeline {
  agent any
  stages {
    stage('Deploy') {
      step { echo 'Deploying...' }
    }
  }
}

medium

A. The keyword should be 'steps' not 'step'

B. Missing agent declaration

C. Stage name must be lowercase

D. Echo command is invalid

Solution

1. Step 1: Check pipeline syntax for stages

   Inside a stage, the correct block is steps (plural), not step.

2. Step 2: Verify other parts

   Agent is declared, stage name case is allowed, echo is valid. Only 'step' is wrong.

3. Final Answer:

   The keyword should be 'steps' not 'step' -> Option A

4. Quick Check:

   Use 'steps' block inside stage = A [OK]

Hint: Inside stage use 'steps' plural block [OK]

Common Mistakes:

• Using 'step' instead of 'steps'
• Thinking stage names must be lowercase
• Assuming echo is not allowed

5. You want to create a Jenkins pipeline that builds, tests, and deploys only if tests pass. Which approach best fits this CI/CD workflow?

hard

A. Skip Test stage and deploy immediately after Build

B. Define sequential stages: Build, Test, Deploy; Deploy runs only if Test succeeds

C. Deploy first, then Build and Test in any order

D. Run Build and Deploy stages in parallel, then Test last

Solution

1. Step 1: Understand CI/CD workflow logic

   Tests must pass before deploying to avoid broken releases.

2. Step 2: Choose pipeline structure

   Sequential stages Build -> Test -> Deploy ensure deploy runs only if tests succeed.

3. Step 3: Evaluate other options

   Parallel or skipping tests risks deploying broken code; deploying first is illogical.

4. Final Answer:

   Define sequential stages: Build, Test, Deploy; Deploy runs only if Test succeeds -> Option B

5. Quick Check:

   Sequential stages with test gate = D [OK]

Hint: Deploy only after successful tests in sequence [OK]

Common Mistakes:

• Running deploy before tests
• Skipping tests to save time
• Running build and deploy in parallel