Pushing images to registry in Jenkins - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this Jenkins pipeline step?

Consider this Jenkins pipeline snippet that pushes a Docker image to a registry:

stage('Push Image') {
  steps {
    script {
      docker.withRegistry('https://myregistry.example.com', 'registry-credentials') {
        def appImage = docker.build('myapp:latest')
        appImage.push()
      }
    }
  }
}

What will Jenkins output if the push is successful?

A Successfully pushed image myapp:latest to https://myregistry.example.com

B Error: No such image: myapp:latest

C Permission denied: failed to push image to registry

D Syntax error in Jenkinsfile at line 3

💡 Hint

Think about what Jenkins logs when a Docker image push succeeds inside docker.withRegistry.

When the image push succeeds, Jenkins logs a success message indicating the image name and registry URL.

❓ Configuration

intermediate

Which Jenkins credential type is required for pushing Docker images?

You want to push Docker images to a private registry from Jenkins. Which credential type should you configure in Jenkins to authenticate properly?

A SSH Username with private key

B Username with password

C Secret text

D Certificate

💡 Hint

Docker registries usually require a username and password for login.

Docker registries authenticate using username and password, so Jenkins credentials of type 'Username with password' are needed.

❓ Troubleshoot

advanced

Why does this Jenkins pipeline fail to push the image?

Given this Jenkins pipeline snippet:

stage('Push Image') {
  steps {
    script {
      def appImage = docker.build('myapp:latest')
      appImage.push()
    }
  }
}

The push step fails with an authentication error. What is the most likely cause?

A Missing <code>docker.withRegistry</code> block to provide registry credentials

B The image name 'myapp:latest' is invalid

C The Jenkinsfile syntax is incorrect

D Docker daemon is not running on the Jenkins agent

💡 Hint

Think about how Jenkins provides credentials to Docker commands.

Without docker.withRegistry, Jenkins does not pass credentials to Docker, causing authentication failure on push.

🔀 Workflow

advanced

What is the correct order of steps to push a Docker image in Jenkins?

Arrange these steps in the correct order to build and push a Docker image to a registry in Jenkins:

A 3,4,1,2

B 4,1,3,2

C 4,3,1,2

D 1,4,3,2

💡 Hint

Think about when authentication must happen relative to building and pushing.

You first define the image name and tag, then authenticate to the registry, then build the image, and finally push it.

✅ Best Practice

expert

Which practice improves security when pushing Docker images in Jenkins?

Which of the following practices best improves security when pushing Docker images to a registry in Jenkins pipelines?

A Store registry credentials as plain text environment variables in Jenkinsfile

B Push images without authentication to speed up the pipeline

C Hardcode registry username and password in the Dockerfile

D Use Jenkins credentials plugin to store and inject registry credentials securely

💡 Hint

Consider how Jenkins manages sensitive information securely.

Using Jenkins credentials plugin securely stores and injects sensitive data without exposing it in code or logs.