What is Continuous Delivery vs Continuous Deployment in Jenkins - Why It Matters

The Big Idea

Discover how automating software delivery can save you hours of tedious work and avoid costly mistakes!

The Scenario

Imagine you have a small shop where you make and sell cakes. Every time you bake a new cake, you have to personally deliver it to each customer. If you have many customers, this takes a lot of time and effort.

The Problem

Delivering cakes by yourself means you can make mistakes like delivering the wrong cake, forgetting some customers, or being very slow. This slows down your business and makes customers unhappy.

The Solution

Continuous Delivery and Continuous Deployment are like having a smart delivery system that automatically packs and sends cakes to customers quickly and correctly. This system reduces mistakes and speeds up delivery.

Before vs After

✗ Before

Bake cake -> Pack cake -> Call delivery person -> Deliver cake

✓ After

Bake cake -> Automated tests -> Auto package -> Auto deploy to customers

What It Enables

It enables fast, reliable, and automatic delivery of software updates to users without manual steps.

Real Life Example

A software team uses Jenkins to automatically test and prepare their app. With Continuous Delivery, they can choose when to release updates. With Continuous Deployment, updates go live automatically after passing tests.

Key Takeaways

Manual delivery is slow and error-prone.

Continuous Delivery automates preparation but lets humans decide when to release.

Continuous Deployment automates the entire release process, making updates instant.

Practice

1. What is the main difference between Continuous Delivery and Continuous Deployment?

easy

A. Continuous Delivery only builds code, Continuous Deployment only tests code.

B. Continuous Delivery deploys every change automatically, Continuous Deployment requires manual approval.

C. Continuous Delivery requires manual approval before production deployment, Continuous Deployment does not.

D. Continuous Delivery and Continuous Deployment are exactly the same.

Solution

1. Step 1: Understand Continuous Delivery

   Continuous Delivery automates preparing the software for release but waits for a manual step to deploy to production.

2. Step 2: Understand Continuous Deployment

   Continuous Deployment automates the entire process, including automatic deployment to production without manual approval.

3. Final Answer:

   Continuous Delivery requires manual approval before production deployment, Continuous Deployment does not. -> Option C

4. Quick Check:

   Manual approval = Continuous Delivery [OK]

Hint: Manual step means Continuous Delivery, no manual means Continuous Deployment [OK]

Common Mistakes:

• Confusing which process needs manual approval
• Thinking both deploy automatically
• Mixing build and deploy steps

2. Which Jenkins pipeline step is typically used to pause for manual approval in Continuous Delivery?

easy

A. input

B. deploy

C. build

D. test

Solution

1. Step 1: Identify Jenkins step for manual pause

   The input step in Jenkins pipeline pauses the pipeline and waits for user approval.

2. Step 2: Confirm other steps roles

   deploy runs deployment, build compiles code, test runs tests, none pause for approval.

3. Final Answer:

   input -> Option A

4. Quick Check:

   Manual approval step = input [OK]

Hint: Pause for approval uses 'input' step in Jenkins [OK]

Common Mistakes:

• Choosing deploy as manual step
• Confusing build or test with approval
• Not knowing Jenkins pipeline steps

3. Given this Jenkins pipeline snippet for Continuous Delivery:

stage('Deploy to Prod') {
  steps {
    input 'Approve deployment?'
    sh 'deploy.sh'
  }
}

What happens when this pipeline reaches the Deploy to Prod stage?

medium

A. The pipeline pauses and waits for manual approval before running deployment.

B. The pipeline fails with a syntax error.

C. The pipeline skips deployment and ends.

D. The deployment script runs immediately without pause.

Solution

1. Step 1: Analyze the input step in the stage

   The input 'Approve deployment?' pauses the pipeline and waits for a user to approve before continuing.

2. Step 2: Understand what happens after approval

   After approval, the shell script deploy.sh runs to deploy the application.

3. Final Answer:

   The pipeline pauses and waits for manual approval before running deployment. -> Option A

4. Quick Check:

   input step causes pause = The pipeline pauses and waits for manual approval before running deployment. [OK]

Hint: input step pauses pipeline until approval [OK]

Common Mistakes:

• Assuming deploy runs immediately
• Thinking pipeline skips deployment
• Confusing syntax error with input step

4. You have a Jenkins pipeline intended for Continuous Deployment but it includes this code:

stage('Deploy') {
  steps {
    input 'Approve deployment?'
    sh 'deploy.sh'
  }
}

What is the problem if you want full Continuous Deployment?

medium

A. The pipeline syntax is invalid and will fail.

B. The input step causes manual approval, breaking full automation.

C. The deploy.sh script is missing required parameters.

D. The stage name should be 'Continuous Deployment' instead of 'Deploy'.

Solution

1. Step 1: Identify manual approval in pipeline

   The input step pauses for manual approval, which is not allowed in full Continuous Deployment.

2. Step 2: Understand Continuous Deployment automation

   Continuous Deployment requires no manual steps; every change deploys automatically.

3. Final Answer:

   The input step causes manual approval, breaking full automation. -> Option B

4. Quick Check:

   Manual approval breaks Continuous Deployment [OK]

Hint: No manual steps allowed in Continuous Deployment [OK]

Common Mistakes:

• Thinking syntax error causes failure
• Assuming deploy.sh script is the problem
• Confusing stage name with functionality

5. You want to convert a Jenkins pipeline from Continuous Delivery to Continuous Deployment. Which change should you make?

hard

A. Rename the pipeline to 'Continuous Deployment' without changing steps.

B. Add more manual approval steps to ensure safety.

C. Change the build step to run tests only.

D. Remove the manual input approval step so deployment runs automatically.

Solution

1. Step 1: Identify manual approval in Continuous Delivery

   Continuous Delivery pipelines pause for manual approval using the input step.

2. Step 2: Remove manual approval for Continuous Deployment

   To achieve Continuous Deployment, remove the input step so deployment happens automatically after tests.

3. Final Answer:

   Remove the manual input approval step so deployment runs automatically. -> Option D

4. Quick Check:

   Remove manual steps for Continuous Deployment [OK]

Hint: Remove input step to automate deployment fully [OK]

Common Mistakes:

• Adding manual steps instead of removing
• Changing unrelated build steps
• Only renaming pipeline without changing logic