Top 20 Red Hat Linux Interview Questions and Answers

• Pawan
• July 8, 2024
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Do you want to work with Linux Enterprise in an MNC? Are you preparing for an Interview for the position of Linux Administrator? If yes, then you are at the right place. Here, you will read about the Top 20 Red Hat Linux Interview Questions and Answers that can help you learn about a simple way to answer questions in an interview regarding your desired position in an MNC’s job opening. Let’s get started!

20 Red Hat Linux Interview Questions and Answers

I. Core Red Hat Linux Concepts (Beginner)

1. What is Linux?

Based on Unix, Linux is an open-source operating system renowned for its flexibility, security, and stability. It is extensively utilized in embedded systems, desktops, and servers.

Linux distributions with different software and tools for different purposes are Ubuntu and Fedora.

2. What is Red Hat Enterprise Linux (RHEL)?

A commercial Linux distribution designed for enterprise use is called Red Hat Enterprise Linux (RHEL). For business applications, it offers a dependable, secure, and highly performant platform with comprehensive support and certification.

Enterprise environments frequently use RHEL for servers, cloud deployments, and mission-critical workloads.

3. Differentiate between Red Hat Enterprise Linux (RHEL) and a free Linux distribution like Ubuntu.

The following are the variations between the free Linux offered by Ubuntu and Red Hat Enterprise Linux (RHEL):

• Cost and Licensing:

1. RHEL: It requires a subscription to access certified software, updates, and official support.
2. Ubuntu: Free to download and use, with Canonical offering optional paid support.

• Support and Maintenance:

1. RHEL: It provides enterprise-level support, which includes long-term support (LTS) versions, security patches, and frequent updates.
2. Ubuntu: It offers official and community support for Long Term Support (LTS) versions, which are usually released more frequently than every five years.

• Target Audience:

1. RHEL: Stability, security, and interoperability with enterprise software are the main priorities in its design for enterprise environments.
2. Ubuntu: It is focused heavily on user-friendliness and was intended for a wide range of users, including desktop and server users.

• Certification and Compatibility:

1. RHEL: A wide range of enterprise applications and hardware are certified for use with it, guaranteeing compatibility and support.
2. Ubuntu: It has a greater variety of hardware and software compatibilities than RHEL, but it might not have the same level of enterprise certification.

• Update and Release Cycle:

1. RHEL: It focuses on long-term stability and support and has a slower, more stable release cycle.
2. Ubuntu: It offers both LTS and non-LTS versions to accommodate varying needs and preferences, along with more frequent updates and releases.

4. List some key features of Red Hat Enterprise Linux.

Red Hat Enterprise Linux (RHEL) is a recommended option for enterprise environments due to several important features it offers:

1. Stability and Reliability,
2. Security,
3. Comprehensive Support,
4. Certified Ecosystem,
5. Performance Optimization,
6. Scalability,
7. Management Tools,
8. Container Support,
9. Long-Term Support, and
10. Comprehensive Documentation.

5. Briefly explain the role of a system administrator for a Red Hat Linux server.

The hardware and software of a Red Hat Linux server must be installed, configured, and maintained by a system administrator. They oversee user accounts, guarantee system security, carry out routine maintenance, and resolve any problems.

To guarantee effective operation, they also optimize resources and keep an eye on system performance.

II. Red Hat Package Management (Intermediate)

6. What is the primary package management tool used in Red Hat Linux?

YUM (Yellowdog Updater, Modified) is the main package management tool used in Red Hat Linux. It manages the installation, updating, and removal of software packages.

YUM has been replaced in more recent iterations by DNF (Dandified YUM), which offers better features and performance. RPM (Red Hat Package Manager) is used by both tools to manage package files.

7. Explain the difference between YUM and RPM.

A low-level tool called RPM (Red Hat Package Manager) is used to install, query, verify, update, and remove individual software packages. A higher-level tool called YUM (Yellowdog Updater, Modified) builds on RPM by automatically managing package repositories and resolving dependencies to make software updates and installations easier.

8. How do you install a new software package using YUM?

Use YUM to install a new software package by issuing the following command:

• sudo yum install package_name

9. How can you update all installed packages to their latest versions using YUM?

Use YUM to update every installed package to the most recent version by running the following command:

• sudo yum update

10. How would you remove an unwanted software package using YUM?

With YUM, you can use the following command to get rid of an undesired software package:

• sudo yum remove package_name

Put the name of the package you wish to uninstall in place of ‘package_name.’ The package that is specified as well as any dependencies that were installed especially for it but are no longer required will be removed by this command.

III. User Management and System Administration (Intermediate)

11. How can you create a new user account on a Red Hat Linux system?

On a Red Hat Linux system, run the following command to create a new user account:

• sudo useradd username

Put the desired username for the new account in place of ‘username.’ Once the account has been created, the new user should choose a password using:

• sudo passwd username

You will then be prompted to enter and validate the user’s new password.

12. Explain the process of changing a user’s password on Red Hat Linux.

To modify a user’s password on a Red Hat Linux system, take the following actions:

1. Open the terminal.
2. Use the username followed by the ‘passwd‘ command. For instance, type the following to update the password for the user ‘username:’

• sudo passwd username

1. When prompted, enter the new password and double-check it by entering it.

13. Describe some basic file manipulation commands in Red Hat (e.g., mv, cp, etc.).

Red Hat includes the following basic file manipulation commands:

1. ‘mv source destination’: Renames or moves a directory or file.
2. ‘cp source destination’: Duplicates a directory or file.
3. ‘rm filename’: Removes a file.
4. ‘mkdir directory_name’: Forms a fresh directory.
5. ‘rmdir directory_name’: Eliminates an empty directory.
6. ‘touch filename’: Either creates a new, empty file or modifies an existing file’s timestamp.
7. ‘ls’: Displays a list of the current directory’s files and directories.

14. How can you check the uptime of a Red Hat Linux server?

Use the following command to determine a Red Hat Linux server’s uptime:

• uptime

15. How would you find out how much memory (RAM) is free on a Red Hat system?

To ascertain the available memory (RAM) on a Red Hat system, execute the subsequent command:

• free -h

This command provides a readable format for the amount of memory that is both free and used.

IV. Advanced Red Hat System Administration (Advanced)

16. How do you start, stop, or restart a service on a Red Hat server?

Using the systemctl command, you can start, stop, or restart a service on a Red Hat server:

1. Start a service:
   sudo systemctl start service_name
2. Stop a service:
   sudo systemctl stop service_name
3. Restart a service:
   sudo systemctl restart service_name

The name of the service you wish to manage should be substituted for service_name.

17. Briefly explain the concept of SELinux in Red Hat and its role in security.

Red Hat Linux’s SELinux (Security-Enhanced Linux) security module imposes required access control rules. It lowers the possibility of unauthorized access and system vulnerabilities by limiting programs’ access to files and resources by establishing policies.

By offering fine-grained control over access permissions, SELinux improves system security as a whole.

18. How can you add a new repository for installing software packages?

Create a new repository file in the directory ‘/etc/yum.repos.d/’ to add a new repository for Red Hat Linux software package installations:

• sudo nano /etc/yum.repos.d/repo_name.repo

Include the repository’s information in the file, for instance:

• [repo_name]
• name=Repository Name
• baseurl=http://example.com/repo/
• enabled=1
• gpgcheck=1
• gpgkey=http://example.com/repo/RPM-GPG-KEY

After saving the file, close the editor. Installing packages from the new repository is now possible with YUM.

19. Describe a troubleshooting approach for a situation where a service fails to start on Red Hat.

There are a few steps you can take to troubleshoot a service that doesn’t start on a Red Hat (or any other Linux system). This is a methodical way to identify and fix the issue:

1. Check the Service Status:

To see the service’s current status, use the ‘systemctl’ command. Information about whether the service is failing, dead, or running is provided by this command.

• sudo systemctl status <service_name>

1. View Logs:

Look for any service-related error messages in the system logs. You can view the logs by using ‘journalctl.’

• sudo journalctl -xe
• sudo journalctl -u <service_name>

1. Check Configuration Files:

Check to make sure the service’s configuration files are accurate. Check for any misconfigurations or syntax errors.

• sudo <service_name> configtest

1. Test Service Manually:

To find out if the service gives you any error messages right away, try starting it manually from the command line.

• sudo /path/to/service –test

1. Check for Dependency Issues:

Verify that the service has been installed and is operating for each and every dependency. To view the dependencies of the service, type’systemctl list-dependencies <service_name>‘.

1. Review Resource Limits:

Resource constraints can occasionally prevent services from starting. Examine the CPU, memory, and disk space among other system resources.

• free -m
• df -h
• top

1. SELinux and Firewall Settings:

Verify whether firewall or SELinux settings are preventing the service from starting.

• sudo setenforce 0 # Temporarily disable SELinux to see if it resolves the issue
• sudo firewall-cmd –list-all

1. Check for Updates:

Make sure the service and your system are up to date. Bugs in previous versions can occasionally lead to the failure of services.

• sudo yum update

1. Look for Known Issues:

Look through the Red Hat knowledge base or community forums to see if there are any known service-related problems.

1. Restart the Service:

Try restarting the service after making any modifications.

• sudo systemctl restart <service_name>

1. Reboot the System:

Rebooting the device might fix problems sometimes.

• sudo reboot

20. What are some benefits of obtaining a Red Hat certification?

A Red Hat certification has several advantages, such as:

1. Industry Recognition,
2. Career Advancement,
3. Hands-on Experience,
4. Access to Red Hat Resources, and
5. Competitive Advantage.

Conclusion

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