Question 1

What is Linux, and what are its core components?

Accepted Answer

Linux is an open-source operating system modeled on UNIX. It powers everything from smartphones to supercomputers and is the dominant operating system for servers and cloud infrastructure.

The kernel is the core of Linux. It manages hardware resources, handles system calls, controls processes, and manages memory. The kernel acts as a bridge between applications and the physical hardware. Different distributions use different kernel versions, but they all share the same fundamental architecture.

The shell is the command-line interface that lets users interact with the system. Bash, which

Question 2

How do you manage users and groups in Linux?

Accepted Answer

Linux uses users and groups to control access to system resources. Proper user management is fundamental to system security.

User information is stored in /etc/passwd. Each line contains username, user ID, group ID, home directory, and default shell. Passwords are stored separately in /etc/shadow for security, readable only by root.

The useradd command creates new users. Use useradd username to create a basic user. Use useradd -m username to create a home directory. Use useradd -s /bin/bash username to set the default shell. Combine options as needed.

The passwd command sets or change

Question 3

Why is Python popular in DevOps? What Python libraries and modules are commonly used for automation?

Accepted Answer

Python has become the go-to language for DevOps automation for several compelling reasons.

First, the syntax is clean and readable. This matters when your scripts need to be maintained by a team. Second, it has an enormous ecosystem of libraries for virtually any task. Third, it handles complex data structures better than Bash, making it ideal when scripts grow beyond simple commands.

Key standard library modules include:

os and pathlib for file system operations
subprocess for running shell commands
json and yaml for configuration parsing
logging for proper log management
argpars

Question 4

Explain exit codes in Bash. What do they mean and how do you use them for error handling in scripts?

Accepted Answer

Exit codes are numeric values that commands return to indicate success or failure. They are fundamental to error handling in shell scripts.

The convention is simple: zero means success, any non-zero value means failure. The special variable $? holds the exit code of the last command executed. Different non-zero values can indicate different types of failures, though the specific meanings vary by program.

Common exit codes include: 0 for success, 1 for general errors, 2 for misuse of shell commands, 126 for permission problems, 127 for command not found, and 128 plus the signal number for

Question 5

What is Jenkins, and how does it work? Can you explain the difference between a Declarative Pipeline and a Scripted Pipeline?

Accepted Answer

Jenkins is an open-source automation server that helps automate the building, testing, and deployment of software. It is one of the most widely used CI/CD tools, known for its flexibility and extensive plugin ecosystem with over 1800 plugins.

Jenkins works by executing jobs, which are collections of steps that perform tasks like compiling code, running tests, or deploying applications. Jobs can be triggered manually, on a schedule, or automatically when code is pushed to a repository. Jenkins can run on a single server or scale across multiple nodes called agents.

The Jenkinsfile is a te

Question 6

What are the different deployment strategies used in CI/CD? When would you use each one?

Accepted Answer

Different deployment strategies offer various tradeoffs between risk, speed, and resource usage. Choosing the right one depends on your application and risk tolerance.

Recreate deployment is the simplest approach. You stop the old version, then start the new version. There is downtime during the switch. This works for development environments or applications where brief downtime is acceptable, but it is not suitable for production systems requiring high availability.

Rolling deployment updates instances gradually. If you have ten servers, you might update two at a time. Traffic shifts to

Question 7

How do you manage and optimize costs in the cloud? What strategies and tools do you use?

Accepted Answer

Cloud cost optimization is an ongoing discipline because without attention, cloud bills grow quickly. The pay-as-you-go model means you pay for what you use, but also for what you forget to turn off.

Start with visibility. You cannot optimize what you cannot measure. Use cloud provider cost tools like AWS Cost Explorer, Azure Cost Management, or GCP Billing. Tag resources consistently so you can attribute costs to teams, projects, or environments. Set up budgets and alerts to catch unexpected spending early.

Right-size your resources. Many instances are over-provisioned. If your applicat

Question 8

What is the difference between public cloud, private cloud, and hybrid cloud? When would you use each?

Accepted Answer

These three deployment models describe where cloud infrastructure is hosted and who has access to it.

Public cloud is owned and operated by a third-party provider and shared among multiple customers. AWS, Azure, and GCP are public clouds. Your workloads run on shared infrastructure, though they are logically isolated from other customers. Public cloud offers the greatest scalability and lowest upfront cost. You benefit from economies of scale because the provider serves millions of customers. Most startups and modern applications use public cloud.

Private cloud is dedicated to a single o

DevOps Engineer

Topics

Linux Fundamentals

Scripting (Bash/Python)

CI/CD Pipelines

Cloud Basics (AWS/GCP/Azure)

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