Linux Admin Interview Questions and Answers For Beginners

 

Q1: How do you secure a Linux server?

A1: Securing a Linux server involves multiple steps: configuring a firewall using tools like iptables or UFW, ensuring regular updates and patches, setting up SSH key authentication, disabling root logins, and implementing fail2ban to prevent brute force attacks. Regularly reviewing security logs and using SELinux for access control play crucial roles.

Q2: Explain the role of the /etc/fstab file in Linux.

A2: The /etc/fstab file is crucial for system startup; it contains information about filesystems and their mounting points. The mount command reads this file to connect file systems at boot time, ensuring that necessary resources are available from the outset.

Q3: How do you monitor system performance in Linux?

A3: Tools like top, htop, iotop, and vmstat are instrumental in monitoring system performance. These utilities provide real-time insights into CPU usage, memory consumption, disk I/O, and process management, helping administrators identify and troubleshoot performance bottlenecks.

Q4: Describe creating a new user and granting them sudo access.

A4: To create a new user, use the useradd command followed by passwd to set a password. For sudo access, edit the /etc/sudoers file with visudo and add the user, specifying the permissions. This grants the user the ability to execute commands with elevated privileges.

Q5: What is LVM, and why is it useful?

A5: Logical Volume Management (LVM) allows for flexible disk management, enabling resizing of disk volumes without downtime. It is useful for efficiently managing disk space, creating backup snapshots, and ensuring data integrity during system expansions.

Linux Interview Questions and Answers for Experienced

Below are the top 5 Linux admin interview questions and answers for experienced professionals.

Q1: How do you manage package installations across multiple systems?

A1: Tools like Ansible, Puppet, or Chef are used to manage package installations. These automation platforms enable consistent package management across environments, streamline configuration tasks, and ensure compliance with desired system states.

Q2: Explain how you would recover a system from a failed disk in a RAID array.

A2: Recovery involves removing the failed disk, replacing it with a new one, and using RAID utilities like mdadm to rebuild the array, ensuring data redundancy and integrity are maintained throughout the process.

Q3: Describe your approach to automating repetitive tasks in Linux.

A3: Automation in Linux can be achieved through scripting in languages like Bash, Python, or Perl. Cron jobs can be scheduled for regular tasks, ensuring efficiency and accuracy in routine operations.

Q4: Discuss the importance of system logging and how you monitor logs.

A4: System logging is vital for diagnosing issues, auditing, and security monitoring. Tools like Syslog, rsyslog, and log rotate manage logs, while utilities like Logwatch and ELK stack provide comprehensive log analysis and visualisation.

Q5: How do you ensure high availability and disaster recovery in Linux environments?

A5: Ensuring high availability involves setting up redundant systems and load balancers. Regular backups, using tools like rsync and Bacula, and testing recovery procedures are essential for disaster recovery to minimise downtime and data loss