Canary deployment pattern in Jenkins - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a Jenkins pipeline stage for canary deployment.

Jenkins

stage('Canary Deployment') {
  steps {
    script {
      sh 'kubectl apply -f [1]'
    }
  }
}

Drag options to blanks, or click blank then click option'

Atest-deployment.yaml

Bproduction-deployment.yaml

Crollback.yaml

Dcanary-deployment.yaml

Attempts:

3 left

💡 Hint

Common Mistakes

Using the production deployment file instead of canary.

The canary deployment YAML file is applied to start the canary release.

2fill in blank

medium

Complete the code to set the percentage of traffic to route to the canary version.

Jenkins

environment {
  CANARY_PERCENT = '[1]'
}

Drag options to blanks, or click blank then click option'

A10%

B50%

C100%

D0%

Attempts:

3 left

💡 Hint

Common Mistakes

Setting 100% traffic immediately, which is not a canary.

Typically, canary deployments start with a small percentage like 10% of traffic.

3fill in blank

hard

Fix the error in the command to update the service to route traffic to the canary deployment.

Jenkins

sh 'kubectl patch svc my-service -p "[1]"'

Drag options to blanks, or click blank then click option'

A{"spec":{"selector":{"version":"test"}}}

B{"spec":{"selector":{"version":"prod"}}}

C{"spec":{"selector":{"version":"canary"}}}

D{"spec":{"selector":{"version":"old"}}}

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'prod' or other labels that do not route to canary.

The service selector must point to the canary version to route traffic correctly.

4fill in blank

hard

Fill both blanks to define a Jenkins pipeline step that waits for the canary deployment to be ready and then verifies it.

Jenkins

stage('Verify Canary') {
  steps {
    sh 'kubectl rollout status deployment/[1]'
    sh 'curl -f http://[2]/health || exit 1'
  }
}

Drag options to blanks, or click blank then click option'

Acanary-app

Bprod-app

Ccanary-service

Dprod-service

Attempts:

3 left

💡 Hint

Common Mistakes

Checking production deployment or service instead of canary.

The rollout status checks the canary deployment named 'canary-app'. The health check uses the canary service URL.

5fill in blank

hard

Fill all three blanks to define a Jenkins pipeline snippet that promotes the canary to production by updating the deployment and service selectors.

Jenkins

stage('Promote Canary') {
  steps {
    sh 'kubectl patch deployment [1] -p "{\"spec\":{\"template\":{\"metadata\":{\"labels\":{\"version\":\"[2]\"}}}}}"'
    sh 'kubectl patch svc [3] -p "{\"spec\":{\"selector\":{\"version\":\"[2]\"}}}"'
  }
}

Drag options to blanks, or click blank then click option'

Aprod-app

Bcanary

Cprod-service

Dcanary-app

Attempts:

3 left

💡 Hint

Common Mistakes

Using canary deployment name instead of production for deployment patch.

The production deployment is patched to use the 'canary' version label. The production service selector is updated to route to the 'canary' version, effectively promoting it.

Practice

1. What is the main purpose of a canary deployment in Jenkins?

easy

A. To release updates to a small group first to reduce risk

B. To deploy all changes to production at once

C. To rollback all changes immediately after deployment

D. To skip testing and deploy directly

Solution

1. Step 1: Understand canary deployment concept

   Canary deployment means releasing updates to a small subset of users first to catch issues early.

2. Step 2: Compare options with this concept

   Only To release updates to a small group first to reduce risk describes releasing to a small group to reduce risk, matching the canary pattern.

3. Final Answer:

   To release updates to a small group first to reduce risk -> Option A

4. Quick Check:

   Canary deployment = small group release [OK]

Hint: Canary means small group first to catch problems early [OK]

Common Mistakes:

• Thinking canary deploys to all users at once
• Confusing canary with rollback process
• Assuming canary skips testing

2. Which Jenkins Pipeline syntax correctly defines separate stages for canary and full deployment?

easy

A. steps { stage('Canary') { echo 'Deploying canary' } stage('Full') { echo 'Deploying full' } }

B. stage('Deploy') { steps { echo 'Deploying canary and full together' } }

C. stage('Canary') { steps { echo 'Deploying canary' } } stage('Full') { steps { echo 'Deploying full' } }

D. stage('Canary and Full') { steps { echo 'Deploying both' } }

Solution

1. Step 1: Identify correct Jenkins Pipeline stage syntax

   Each stage must be defined with stage('name') { steps { ... } } blocks.

2. Step 2: Check which option uses separate stages for canary and full deployment

   stage('Canary') { steps { echo 'Deploying canary' } } stage('Full') { steps { echo 'Deploying full' } } correctly defines two separate stages named 'Canary' and 'Full' with steps inside.

3. Final Answer:

   stage('Canary') { steps { echo 'Deploying canary' } } stage('Full') { steps { echo 'Deploying full' } } -> Option C

4. Quick Check:

   Separate stages = stage('Canary') { steps { echo 'Deploying canary' } } stage('Full') { steps { echo 'Deploying full' } } [OK]

Hint: Separate canary and full deploy in different stages [OK]

Common Mistakes:

• Putting stages inside steps block incorrectly
• Combining canary and full in one stage
• Missing steps block inside stage

3. Given this Jenkins Pipeline snippet, what will be the output during the canary stage?

pipeline {
  agent any
  stages {
    stage('Canary') {
      steps {
        echo 'Starting canary deployment'
      }
    }
    stage('Full') {
      steps {
        echo 'Starting full deployment'
      }
    }
  }
}

medium

A. Starting canary deployment\nStarting full deployment

B. Starting full deployment

C. Starting canary deployment

D. No output

Solution

1. Step 1: Understand Jenkins Pipeline stage execution

   Stages run sequentially. The 'Canary' stage runs first and prints its echo message, then the 'Full' stage runs and prints its message.

2. Step 2: Identify output during the entire pipeline run

   When the pipeline runs fully, both 'Starting canary deployment' and 'Starting full deployment' are printed sequentially.

3. Final Answer:

   Starting canary deployment Starting full deployment -> Option A

4. Quick Check:

   Pipeline output = both stage messages in order [OK]

Hint: Each stage prints its own echo message when running sequentially [OK]

Common Mistakes:

• Assuming all stages print output at once
• Confusing canary stage output with full stage
• Thinking no output appears during stages

4. You wrote this Jenkins Pipeline snippet for canary deployment but it fails with syntax error:

pipeline {
  agent any
  stages {
    stage('Canary')
      steps {
        echo 'Deploying canary'
      }
    }
  }
}

What is the error?

medium

A. Extra closing brace after steps block

B. Incorrect agent declaration

C. Missing echo command inside steps

D. Missing curly braces after stage('Canary') declaration

Solution

1. Step 1: Check stage syntax in Jenkins Pipeline

   The stage('Canary') must be followed by a block enclosed in curly braces { ... }.

2. Step 2: Identify missing braces causing syntax error

   The snippet misses opening curly brace after stage('Canary'), causing syntax error.

3. Final Answer:

   Missing curly braces after stage('Canary') declaration -> Option D

4. Quick Check:

   Stage needs braces {} after declaration [OK]

Hint: Always add braces {} after stage('name') [OK]

Common Mistakes:

• Forgetting braces after stage declaration
• Misplacing steps block outside stage
• Incorrect indentation causing confusion

5. You want to implement a canary deployment in Jenkins that deploys to 10% of users first, then 100% if no errors. Which approach best fits this requirement?

hard

A. Deploy 100% immediately and rollback if errors occur

B. Use separate Jenkins stages: one for 10% canary deploy, monitor, then full deploy stage

C. Deploy 10% and skip monitoring to save time

D. Deploy 50% first, then 50% later without monitoring

Solution

1. Step 1: Understand canary deployment best practice

   Canary deployment requires deploying to a small subset (10%) first, then monitoring for errors before full rollout.

2. Step 2: Match approach to requirement

   Use separate Jenkins stages: one for 10% canary deploy, monitor, then full deploy stage uses separate stages for canary and full deployment with monitoring in between, fitting the requirement best.

3. Final Answer:

   Use separate Jenkins stages: one for 10% canary deploy, monitor, then full deploy stage -> Option B

4. Quick Check:

   Canary deploy + monitor + full deploy = Use separate Jenkins stages: one for 10% canary deploy, monitor, then full deploy stage [OK]

Hint: Deploy small group, monitor, then full deploy [OK]

Common Mistakes:

• Skipping monitoring after canary deploy
• Deploying full immediately without canary
• Choosing wrong canary percentage