Operate Running Systems

Boot and reboot systems into different targets. Interrupt the boot process to reset root passwords. Manage processes, tuned profiles, and system journals. Secure file transfer between hosts.

Labs in this module

Boot, Reboot, Shutdown - Control services and system power with systemctl. is-active for the now, is-enabled for the boot, status for the full Loaded and Active pict
Boot into Different Targets - Tell a RHEL 10 machine which world to boot into with systemd targets. Read the default with systemctl get-default, change it persistently wi
Reset the Root Password - Recover a lost root password on RHEL 10 with rd.break. Interrupt GRUB, append rd.break to the kernel line, boot with Ctrl-x, then at switch_
Process Triage - Find a misbehaving process, then signal it correctly. List with ps -ef and ps aux, watch live with top, read the signals menu with kill -l,
nice and renice - Control process priority with nice and renice. The niceness scale from -20 (highest priority) to 19 (lowest), the default 0, launching at a
tuned Profiles - Tune a RHEL 10 machine by naming its kind, not turning knobs by hand. Read the running profile with tuned-adm active, see the menu with tune
journald: Persistent Journals - Read the systemd journal with journalctl and make it survive reboots. Filter by unit with -u, by severity with -p err, by time with --since,
rsyslog and /var/log - Route system logs with rsyslog. The three files that matter (/var/log/messages, /var/log/secure, /var/log/cron), the facility.priority selec
scp and sftp Secure Transfer - Move a file safely between two hosts over ssh. scp up and scp down with the colon marking the remote side, scp -r for whole directories, the
Mission Control: Operation Steady State - The RHCSA operating-systems capstone on a real RHEL 10 machine. A misconfigured server, brought to a persistent steady state, graded on live