RHCSA Exam Study Guide with Complete Solutions

RHCSA Exam Study Guide with Complete Solutions commands/process to reset root password - Answer️️ -on boot: select most recent kernel `e` to edit goto line with linux16, add `` to end of line `ctrl+x` to continue boot to rd rescue mode remount /sysroot as readable (defaults to read only in rd rescue mode): `mount -o remount,rw /sysroot` load the target env with: `chroot /sysroot` reset the password with: `passwd root` fix selinux context with (instructs selinux to perform full relabel on next reboot): `touch /.autorelabel` fix bootloader config issues (kernel not found or similar error) - Answer️️ -edit boot config confirm boot config is correct and make changes (spelling errors, etc) ©SOPHIABENNET@2024/2025 Tuesday, August 20, 2024 10:21 AM 2 add `=t` to the end of the linux16 line regenerate grub config with the following command: `grub2-mkconfig -o /boot/grub2/` To diagnose boot issues more easily, you decide to disable 'quiet boot' and 'graphical boot' by removing 'quiet' and 'rhgb' from the kernel boot parameters. How would you accomplish this so it's persistent? - Answer️️ -Edit the 'GRUB_CMDLINE_LINUX' line in '/etc/default/grub' then regenerate the bootloader config using 'grub2- mkconfig -o /boot/grub2/'. Under normal circumstances, what is systemd's PID (Process ID)? - Answer️️ -PID 1 - because it's the very first binary called by the kernel at boot, and is responsible for starting up all other processes. Which rescue parameter would you pass to the kernel from the grub2 menu if your system was failing to boot because a filesystem check was failing? - Answer️️ -=t Booting to the emergency target state drops to a rescue shell after the 'root' filesystem has been mounted readonly, but BEFORE other FS checks are carried out. Although you could do the same with '' it would require considerably more effort. You are a member of a team of admins who are responsible for a critical system. This system has two different web servers installed: The first ©SOPHIABENNET@2024/2025 Tuesday, August 20, 2024 10:21 AM 3 (Nginx) is used to serve content, the other (httpd) is installed only to satisfy dependencies and should never be started as it causes a conflict. What command could you run to ensure that 'httpd' is never accidentally started or enabled by another admin? - Answer️️ -systemctl mask httpd You're having a bad day and accidentally delete the 'initramfs' file in /boot that matches your current kernel. Which command would you run to recover from this? - Answer️️ -dracut You've just made a configuration change to the 'SSHD' service and want to daemon to reload it's configuration without disconnecting anyone. How could you accomplish this? - Answer️️ -systemctl reload ce persistent hostname change with systemd - Answer️️ -hostnamectl set- hostname command to show open/listening ports - Answer️️ -ss -taupen t = tcp a = all types of connections (sending as well as listening) u = udp p = process ids (and information about the processes that are holding those ports e = extra information n = numbers only (don't resolve the hostnames) ©SOPHIABENNET@2024/2025 Tuesday, August 20, 2024 10:21 AM 4 replacement for nslookup - Answer️️ -dig replacement for traceroute - Answer️️ -tracepath use mtr for real time updates (may need a yum install) replacement for netstat - Answer️️ -ss create a second connection profile for device enp0s8 named STATIC - Answer️️ -nmcli connection add con-name STATIC sses 192.168.58.1/24 if name enp0s8 type ethernet #verify: nmcli connection show STATIC | less #add an additional dns server (172.16.58.254) - will require route to 172.16.0.0/16 subnet nmcli connection modify STATIC +s "172.16.0.0/16