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Quiz

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DevOps / Jenkins CI-CD

Q1. What does Continuous Integration (CI) specifically solve in a development workflow?

  • A. It automatically deploys every commit directly to production
  • B. It manages infrastructure provisioning using declarative configuration files
  • C. It catches integration bugs early by automatically building and testing on every commit, before changes are merged to the main branch
  • D. It enforces code style and formatting rules by failing builds on violations
Answer

C — Catches integration bugs early.

Without CI, developers integrate their changes infrequently. When they do, they discover conflicts and bugs that have accumulated over days or weeks — the longer the delay, the harder the merge. CI forces frequent small integrations and runs automated tests on each one, catching problems when they are cheap to fix.

Q2. In the Jenkins pipeline, why is Maven called with the -B flag (mvn -B clean install)?

  • A. It enables batch compilation, compiling all modules simultaneously
  • B. It enables batch mode — suppressing interactive prompts that would hang an unattended CI job
  • C. It enables binary output, producing native executables instead of JARs
  • D. It enables background execution, allowing the build to run as a daemon
Answer

B — Batch mode disables interactive prompts.

CI pipelines run unattended with no terminal. Maven's default output includes progress indicators and may prompt for input in certain situations. -B (batch mode) disables these, producing machine-friendly output and preventing the build from hanging waiting for input that will never come.

Q3. What does docker buildx build --platform linux/amd64,linux/arm64 achieve in the Jenkins pipeline?

  • A. It builds two separate images and pushes them with different tags
  • B. It creates a multi-platform manifest — a single image tag that resolves to the correct architecture binary on any host
  • C. It builds the image twice for redundancy
  • D. It enables cross-compilation in Docker, running the build on both platforms simultaneously
Answer

B — Multi-platform manifest under one tag.

Developers often use Apple Silicon Macs (arm64) while production runs on x86 servers (amd64). A multi-platform build creates both binaries and publishes them under a single tag (e.g., myapp:latest). Docker automatically selects the correct binary for the host architecture when pulling.

Q4. Why are Docker Hub credentials stored in Jenkins Credential Store rather than directly in the Jenkinsfile?

  • A. Jenkins cannot read environment variables in a Jenkinsfile
  • B. Storing credentials in the credential store means they are never written to disk or visible in logs — and the Jenkinsfile (which is committed to the repository) never contains secrets
  • C. Docker Hub requires Jenkins-specific authentication tokens
  • D. The Jenkinsfile format does not support string interpolation for credentials
Answer

B — Secrets never written to disk or visible in logs.

Jenkins injects credentials at runtime via withCredentials([usernamePassword(...)]). The actual token is masked in console output (****), never stored in the workspace, and never appears in the Jenkinsfile. Hardcoding credentials in the Jenkinsfile would commit them to the repository — a critical security vulnerability.

Q5. The Jenkins pipeline has a Deploy stage that runs kubectl apply. What must be configured in Jenkins for this to work?

  • A. The Jenkins master must run inside the target Kubernetes cluster
  • B. A kubeconfig file (with cluster credentials and API server URL) must be available to the pipeline — typically mounted or stored as a Jenkins secret
  • C. kubectl is built into Jenkins and requires no additional configuration
  • D. The Kubernetes cluster must have Jenkins installed as a plugin
Answer

B — kubeconfig with cluster credentials.

kubectl uses a kubeconfig file to authenticate to the API server. In Jenkins, this is typically stored as a Secret file credential and injected into the pipeline with withCredentials. The file contains the cluster's CA certificate, the API server URL, and a service account token with sufficient RBAC permissions for the deploy.