1. What is the CI/CD process in your organization?
This is a common interview question to understand your real experience.
You should answer by describing the tools your organization uses.
Example structure explained in your content:
Assume your company uses Java.
Jenkins is the main orchestrator.
Different tools are connected with Jenkins: Maven, Sonar, AppScan, Argo CD, Kubernetes, Helm, etc.
Explain how a developer commits code to GitHub.
Jenkins pipeline automatically triggers and pulls the code.
Jenkins builds the code (e.g., with Maven).
It performs code quality checks or security checks (e.g., Sonar, AppScan).
Then the application is promoted to Dev using Argo CD and Kubernetes.
Argo CD watches the Git repository and deploys new versions using updated image tags and Helm charts.
If Kubernetes is difficult, you can say you deploy to EC2 instead.
The content also refers to a Jenkins pipeline example in the GitHub repository that updates Kubernetes manifests and lets Argo CD deploy based on GitOps.
2. What are the different ways to trigger Jenkins pipelines?
Since Jenkins and GitHub are separate tools, Jenkins must know when new code is pushed.
There are three methods:
Poll SCM
Build triggers (Cron)
Webhooks
Explanation from your content:
Polling and Cron jobs are inefficient because Jenkins repeatedly checks GitHub, which consumes resources and can have time delays.
Webhooks are the best method:
When a developer commits code, GitHub sends a JSON payload to Jenkins.
GitHub notifies Jenkins through an API.
Jenkins receives the payload and triggers the pipeline.
3. How to back up Jenkins?
For Jenkins administration roles, backup is important.
Summary from your content:
The main folder to back up is .jenkins from the Jenkins home directory.
This folder contains jobs, logs, and configuration.
Use tools like rsync to sync backups to storage (EBS or other).
Some large organizations store Jenkins data in external databases, so those databases must be backed up as well.
Plugins or user content may need separate backup steps.
4. How do you store or handle secrets in Jenkins?
Secrets must never appear in logs or UI.
Jenkins provides credential plugins, but the recommended explanation:
Use external secret managers such as HashiCorp Vault.
Jenkins integrates with Vault.
Pipelines fetch secrets from Vault during runtime.
5. What is the latest version of Jenkins?
Interviewers ask this to check whether you actually use Jenkins regularly.
Not knowing the current version can give a bad impression.
If you claim to be a CI/CD engineer using Jenkins, you must stay updated.
6. What are shared modules in Jenkins?
Shared modules/shared libraries mean:
A DevOps engineer writes a pipeline once.
Many development teams reuse that pipeline.
This avoids each team rewriting the same logic.
It’s a reusable pipeline approach.
7. Can Jenkins build applications using multiple programming languages with different agents?
Yes.
Explanation in your content:
Example: frontend (Node.js), backend (Java), microservice (Python).
Jenkins can run multiple stages using different Docker agents.
Each stage uses a separate Docker container with required dependencies.
Containers are removed after pipeline execution, saving resources.
8. How to set up Auto Scaling Groups with Jenkins?
Some companies need multiple worker nodes.
Explanation:
Jenkins master runs on one EC2 instance.
Many teams may need many worker nodes.
Load can increase during certain periods.
Auto Scaling Groups in AWS automatically add/remove Jenkins worker nodes.
This prevents unused nodes from wasting costs.
9. How to add a new worker node in Jenkins?
Summary:
Go to Manage Jenkins → Manage Nodes and Clouds.
Add a new node.
Provide IP address, SSH keys, authentication.
Launch the node to make it active.
10. How to install plugins in Jenkins?
Two ways:
UI Method
CLI Method
Use a Java command to install plugins directly
Useful for automation or when installing many plugins at once
Some plugins must be manually uploaded if not available in the plugin catalog.
11. What is JNLP and why is it used?
Explanation:
JNLP is a way for Jenkins agents (workers) to communicate with Jenkins master.
You download a JNLP JAR and run it on the agent.
It allows remote launch and communication.
The agent receives build tasks from the master.
12. What are some common Jenkins plugins?
Interviewers check your practical experience.
The content suggests:
Be familiar with common plugins.
Look at which plugins Jenkins installs by default.
Prepare a list to avoid blanking during interviews.
Wrap-up
The speaker ends by saying:
These are the main interview questions.
The repository contains detailed answers.
You can submit pull requests if something is missing.
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