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What to expect in the Linux Interview?
When interviewing for a DevOps engineer position focusing on Linux, expect questions that challenge your expertise in managing complex Linux environments, system optimization, troubleshooting, networking, security, and administration.
1: Linux System Optimization
● Kernel Tuning: Be prepared to discuss how you've used sysctl for kernel parameter tuning to optimize system performance.
● Performance Monitoring: Expect questions on tools like top, htop, vmstat, iostat, and sar, and how you use them to identify and resolve performance bottlenecks.
● Resource Management: Discuss strategies for managing system resources such as CPU, memory, and I/O, including cgroups and Linux OOM (Out of Memory) settings.
2: Advanced Linux Troubleshooting
● System Recovery: You might be asked about times you've had to recover a Linux system from boot failures, kernel panics, or filesystem corruption.
● Log Analysis: Be ready to explain how you analyze system and application logs to troubleshoot issues using tools like journalctl, dmesg, and log files in /var/log.
● Network Troubleshooting: Discuss your approach to diagnosing network issues on Linux, including using ip, netstat, ss, tcpdump, and traceroute.
3: Networking and Security
● Firewall and Packet Filtering: Expect to answer questions about configuring and managing firewalls using iptables, nftables, or firewalld.
● SSH Hardening: Discuss methods to secure SSH, such as key-based
authentication, changing default ports, and configuring SSHD options.
● SELinux and AppArmor: You should explain how you've used these security modules to enforce access controls and protect against vulnerabilities.
4: Linux Administration and Automation
● Scripting and Automation: Be prepared to discuss how you've automated routine tasks and deployments using shell scripts, Python, or other scripting languages.
● Package Management: Expect questions on managing software and
dependencies using package managers (apt, yum, dnf), and custom repository setups for package distribution.
● Service Management: Discuss your experience managing services and daemons, including using systemd and init.d scripts and creating custom service units for application management.
5: Storage and File Systems
● LVM and RAID: Be ready to explain how you've configured and managed Logical Volume Manager (LVM) and RAID arrays for performance and redundancy.
● Network File Systems: Discuss your experience setting up and managing network file systems like NFS or Samba for shared storage solutions.
● Backup and Recovery: Questions may cover backup strategies, tools (like rsync, tar, dump, and restore), and disaster recovery planning.