EX200 Red Hat Certified System Administrator - RHCSARHEL 10 Questions and Answers

Solution:

mkdir -p /root/d1

find /usr/local -type f -size +3k -size -5k -exec cp -rvf {} /root/d1/ \;

chmod g+s /root/d1

ls -ld /root/d1

Detailed Explanation:

-size +3k means greater than 3 KB.

-size -5k means less than 5 KB.

chmod g+s sets the SGID bit on the directory.

SGID on a directory causes new files created there to inherit the directory’s group.

Solution:

groupadd admin

mkdir -p /common/admin

chgrp admin /common/admin

chmod 2770 /common/admin

Detailed Explanation:

groupadd admin creates the group.

chgrp admin assigns the group ownership.

2770 means:

2 = SGID

7 = owner rwx

7 = group rwx

0 = others no access

This is a standard shared group-admin directory design.

Solution:

Create the destination directory if needed:

mkdir -p /root/tomfiles

Find and copy:

find / -type f -user tom -exec cp -pvf {} /root/tomfiles/ \;

Detailed Explanation:

find / searches the whole filesystem.

-type f restricts results to files.

-user tom matches owner tom.

-exec cp -pvf copies each file with verbose and force options.

mkdir -p is added as a safe preparation step.

Solution:

Create timer unit:

cat > /etc/systemd/system/backup-now.timer < < 'EOF'

[Unit]

Description=Daily backup timer

[Timer]

OnCalendar=*-*-* 02:00:00

Persistent=true

[Install]

WantedBy=timers.target

EOF

Enable it:

systemctl daemon-reload

systemctl enable --now backup-now.timer

systemctl list-timers --all | grep backup-now

Detailed Explanation:

OnCalendar=*-*-* 02:00:00 means daily at 02:00.

Persistent=true runs missed jobs after boot if the system was off.

timers.target is the normal target for timer units.

RHEL 10 documentation includes systemd timer units as a standard scheduling mechanism. ( Red Hat Documentation )

Solution:

mkdir -p /webdata

semanage fcontext -a -t httpd_sys_content_t "/webdata(/.*)?"

restorecon -Rv /webdata

ls -Zd /webdata

Detailed Explanation:

semanage fcontext defines a persistent SELinux file-context rule.

restorecon applies the correct labels to the directory and contents.

httpd_sys_content_t is the standard read-only content type for Apache.

RHEL 10 SELinux documentation covers persistent labeling with semanage and applying labels with restorecon. ( Red Hat Documentation )

Solution:

dnf install -y tuned

systemctl enable --now tuned

tuned-adm recommend

tuned-adm profile virtual-guest

tuned-adm active

Detailed Explanation:

The lab text uses yum, but on RHEL 10 dnf is the preferred package manager command. RHEL 10 documentation focuses on DNF behavior and changes.

tuned-adm recommend shows the best-fit tuning profile.

tuned-adm profile virtual-guest activates the profile.

tuned-adm active confirms it.

Solution:

echo "john" > > /etc/cron.deny

Detailed Explanation:

cron.deny blocks listed users from using cron.

This is the simplest way to deny scheduled-job access for one user.

Solution:

Reboot the system.

Interrupt GRUB boot.

Press e to edit the boot entry.

On the linux line, append:

rd.break

Boot with Ctrl+x.

At the emergency shell:

mount -o remount,rw /sysroot

chroot /sysroot

passwd root

touch /.autorelabel

exit

exit

Detailed Explanation:

rd.break drops you into an early emergency environment.

/sysroot contains the real root filesystem.

mount -o remount,rw /sysroot makes it writable.

chroot /sysroot changes into the installed system.

passwd root resets the password.

touch /.autorelabel is critical so SELinux relabels files on next boot.

Solution:

dnf install -y autofs

mkdir -p /shares

echo "/shares /etc/auto.shares" > > /etc/auto.master

echo "projects -fstype=nfs,rw server1:/srv/nfs/projects" > /etc/auto.shares

systemctl enable --now autofs

ls /shares/projects

Detailed Explanation:

/etc/auto.master defines the main map.

/etc/auto.shares defines the indirect mount entry.

The mount happens on demand when /shares/projects is accessed.

RHEL 10 file-system documentation includes AutoFS for on-demand mounts. ( Red Hat Documentation )