Node.js Basics:
Q: What is Node.js, and why is it popular in DevOps practices?
- A: Node.js is a JavaScript runtime built on the V8 JavaScript engine. It is popular in DevOps due to its non-blocking I/O, event-driven architecture, and the ability to use JavaScript on both the client and server side.
Q: Explain the event-driven architecture of Node.js.
- A: Node.js is event-driven, meaning it operates based on events and callbacks. It uses an event loop to handle asynchronous operations, making it efficient for tasks such as handling multiple concurrent connections.
npm Basics:
Q: What is npm, and how does it complement Node.js?
- A: npm (Node Package Manager) is the default package manager for Node.js. It complements Node.js by providing a centralized repository for sharing and managing Node.js packages (libraries and tools).
Q: How do you install a Node.js package using npm?
- A: You can install a Node.js package using the following command:
npm install <package-name>. The package and its dependencies will be downloaded and installed in thenode_modulesdirectory.
Dependency Management:
Q: What is the purpose of package.json in a Node.js project?
- A:
package.jsonis a metadata file that contains project information, dependencies, and configuration settings. It is crucial for managing and documenting Node.js projects.
Q: How do you manage dependencies across different environments (development, testing, production) in a Node.js project?
- A: Dependency versions can be managed using the
dependenciesanddevDependenciessections in thepackage.jsonfile. Tools like npm scripts can be used to manage environment-specific configurations.
npm Scripts:
Q: Explain the purpose of npm scripts.
- A: npm scripts are user-defined scripts that can be run using the
npm runcommand. They are defined in thescriptssection of thepackage.jsonfile and are commonly used for tasks like building, testing, and deployment.
Q: How can you execute a specific npm script?
- A: You can execute a specific npm script using the
npm run <script-name>command. For example,npm run buildwill execute the "build" script.
Package Versioning:
Q: What is semantic versioning (SemVer), and how does npm use it?
- A: Semantic versioning is a versioning scheme that follows the format MAJOR.MINOR.PATCH. npm uses SemVer for package versioning, where MAJOR indicates backward-incompatible changes, MINOR indicates backward-compatible additions, and PATCH indicates backward-compatible bug fixes.
Q: How do you update dependencies to their latest versions in a Node.js project?
- A: You can update dependencies to their latest versions using the
npm updatecommand. To update a specific package, usenpm update <package-name>.
Security and Auditing:
Q: How can you check for known vulnerabilities in Node.js dependencies?
- A: You can use the
npm auditcommand to check for known vulnerabilities in Node.js dependencies. The audit command provides information on vulnerabilities and recommends fixes.
Q: Explain how npm handles security through package signing.
- A: npm provides package signing to ensure the integrity and authenticity of packages. Packages are signed using GPG, and npm verifies the signature during installation.
Global vs. Local Packages:
Q: What is the difference between global and local installation of Node.js packages?
- A: Local installation installs packages in the project's
node_modulesdirectory, making them available only for that project. Global installation installs packages globally, making them accessible across different projects.
Q: When would you prefer a global installation of a Node.js package?
- A: Global installation is preferred for packages that provide command-line tools or utilities that you want to use across different projects.
Handling Multiple Node.js Versions:
Q: How can you manage multiple versions of Node.js on your machine?
- A: Tools like nvm (Node Version Manager) can be used to manage multiple versions of Node.js. nvm allows you to switch between different Node.js versions easily.
Continuous Integration (CI) and Deployment:
Q: How can you integrate Node.js projects with CI/CD pipelines?
- A: Node.js projects can be integrated with CI/CD pipelines by defining build and deployment steps using tools like Jenkins, Travis CI, GitLab CI, or GitHub Actions.
Q: What is the role of npm in a CI/CD pipeline?
- A: npm is used in a CI/CD pipeline to install project dependencies, run build scripts, and prepare the application for deployment. It ensures that the required dependencies are available during the build process.
Performance and Scaling:
Q: How does Node.js support scalability in applications?
- A: Node.js supports scalability through its non-blocking, event-driven architecture. It can handle a large number of concurrent connections efficiently, making it suitable for building scalable applications.
Q: Explain the concept of clustering in Node.js.
- A: Clustering in Node.js involves creating multiple instances (workers) of the application to distribute the load across multiple CPU cores. This enhances performance and improves the application's ability to handle more requests.
Debugging and Monitoring:
Q: How can you debug a Node.js application?
- A: Node.js applications can be debugged using the built-in debugger or by using third-party tools like
debugandndb. The--inspectflag can be used to enable debugging.
These questions cover a range of Node.js and npm concepts relevant to DevOps engineers. Depending on the specific requirements of the position, interviewers might delve deeper into areas like CI/CD integration, security practices, or performance optimization.