Canary deployment pattern in Jenkins - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Canary Deployment Purpose

What is the main goal of using a canary deployment in a Jenkins pipeline?

A To rollback all previous versions automatically

B To deploy new code to all users at once to save time

C To test new code on a small subset of users before full rollout

D To run all tests in parallel before deployment

💡 Hint

Think about minimizing risk when releasing new software.

Canary deployment gradually exposes new code to a small group of users to catch issues early before full deployment.

💻 Command Output

intermediate

Jenkins Pipeline Stage Output for Canary Deployment

Given this Jenkins pipeline snippet for canary deployment, what will be the output of the Deploy Canary stage if the deployment succeeds?

Jenkins

stage('Deploy Canary') {
  steps {
    echo 'Deploying to 10% of users'
    sh 'kubectl apply -f canary-deployment.yaml'
    echo 'Canary deployment successful'
  }
}

A Deploying to 10% of users\nCanary deployment successful

B Deploying to 100% of users\nCanary deployment successful

C Error: Deployment failed

D Deploying to 10% of users\nDeployment failed

💡 Hint

Look at the echo statements and the deployment percentage.

The stage prints messages before and after applying the canary deployment manifest, indicating success for 10% users.

❓ Configuration

advanced

Configuring Jenkinsfile for Canary Deployment Rollback

Which Jenkinsfile snippet correctly implements a rollback step if the canary deployment test fails?

A

stage('Canary Test') {
  steps {
    script {
      if (!sh(script: 'run_canary_tests.sh', returnStatus: true) == 0) {
        sh 'kubectl rollout undo deployment/my-app-canary'
      }
    }
  }
}

B

stage('Canary Test') {
  steps {
    script {
      if (sh(script: 'run_canary_tests.sh', returnStatus: true) != 0) {
        sh 'kubectl rollout undo deployment/my-app-canary'
      }
    }
  }
}

C

stage('Canary Test') {
  steps {
    script {
      if (sh(script: 'run_canary_tests.sh', returnStatus: false) != 0) {
        sh 'kubectl rollout undo deployment/my-app-canary'
      }
    }
  }
}

D

stage('Canary Test') {
  steps {
    script {
      if (sh(script: 'run_canary_tests.sh') == 0) {
        sh 'kubectl rollout undo deployment/my-app-canary'
      }
    }
  }
}

💡 Hint

Check how the shell command status is checked and when rollback should happen.

The rollback should trigger if the test script returns a non-zero status. Option B correctly checks for non-zero and triggers rollback.

🔀 Workflow

advanced

Order of Steps in a Canary Deployment Pipeline

Arrange the following steps in the correct order for a Jenkins pipeline implementing a canary deployment:

• Run canary tests
• Deploy to full production
• Deploy to canary subset
• Monitor canary metrics

A 2,1,3,4

B 1,3,2,4

C 3,1,2,4

D 1,2,3,4

💡 Hint

Think about deploying first, then testing and monitoring before full rollout.

The correct order is deploy to canary, run tests, monitor metrics, then deploy fully if all is good.

❓ Troubleshoot

expert

Diagnosing Jenkins Canary Deployment Failure

In a Jenkins pipeline, the canary deployment stage runs but the new version is not serving traffic. Which of the following is the most likely cause?

A The canary deployment manifest has the wrong selector labels, so traffic is not routed to the new pods

B The Jenkinsfile syntax is incorrect, causing the deployment to fail

C The rollback command was triggered prematurely

D The Jenkins agent does not have permission to run shell commands

💡 Hint

Consider why new pods might not receive traffic despite successful deployment.

If the deployment selector labels do not match the service selectors, traffic won't reach the new pods even if deployment succeeds.