Linux System Administration Fundamentals Questions

Core Linux administration knowledge and hands on operational skills required to install, configure, and maintain Linux systems. Covers user and group management, file permissions and ownership, process management and signals, package management across distributions, the boot process and runlevels or targets, basic systemd service control, filesystem navigation and basic disk management, common system configuration files, shell and command line proficiency, and differences between major enterprise and community distributions. Candidates should demonstrate practical troubleshooting of routine issues, patching and updates, and an ability to perform day to day administration tasks reliably.

HardTechnical

33 practiced

You have six identical disks attached to a Linux server and must create a software RAID configuration that tolerates two simultaneous disk failures while maximizing usable capacity and reasonable rebuild times. Which RAID level would you choose and why? Provide mdadm commands to create the array with a hot-spare, configure automatic assembly at boot, and steps to monitor and replace failed drives.

MediumTechnical

33 practiced

You run hundreds of containers per host and observe 'too many open files' and conntrack table exhaustion. Which host-level kernel and sysctl settings would you tune (for example, fs.inotify, fs.file-max, net.netfilter.nf_conntrack_max, ip_local_port_range), and how would you apply and validate these settings safely across a fleet?

HardTechnical

33 practiced

Design a backup and restore strategy for a Linux host that must protect /etc, /var/lib/mysql, and /home with an RTO of 1 hour and RPO of 15 minutes. Include choice of tools (e.g., LVM snapshots, Percona XtraBackup, rsync, borg/restic), backup frequency, retention policy, restore steps for full and point-in-time recovery, and verification/testing approach.

MediumTechnical

27 practiced

You are hardening SSH on production servers. Provide a secure example /etc/ssh/sshd_config snippet to disable root login, disable password authentication, restrict logins to users alice and deploy, set an idle session timeout, and reduce authentication attempts. Explain trade-offs of changing the SSH port and why key management matters in production.

MediumTechnical

33 practiced

Compare cron jobs versus systemd timers: when is each appropriate? Provide an example pair of systemd .service and .timer files that run /usr/local/bin/backup daily at 02:00 (consider timezone handling) and show commands to enable and verify the timer.

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