EX200 Deploy, configure, and maintain systems Practice Test 3 — 15 Questions

Question 1

An administrator extends a logical volume by 5GB. The filesystem is XFS. Which command must be run to make the additional space available?

Accepted Answer

xfs_growfs /mount. After extending a logical volume with lvresize, the XFS filesystem does not automatically recognize the new space. The xfs_growfs command must be run on the mounted filesystem to expand it to fill the enlarged logical volume. This command can target the mount point directly and works online without unmounting.

Answer

mount -o remount /mount

Answer

resize2fs /dev/vg/lv_root

Answer

lvresize -L +5G /dev/vg/lv_root

Question 2

A system fails to boot with an error about a missing ext4 filesystem. From the rescue environment, which command should be run to attempt automatic repair of all filesystems?

Accepted Answer

fsck -A -y. `fsck -A -y` automatically checks all filesystems listed in `/etc/fstab` (the `-A` flag) and answers 'yes' to any repair prompts (the `-y` flag), making it the most appropriate command for automatic repair of all filesystems from a rescue environment. The error indicates a missing ext4 filesystem, and this command will attempt to repair any ext4 (or other) filesystem issues without manual intervention.

Answer

fsck /dev/sda1

Answer

debugfs -R 'repair'

Answer

e2fsck -p

Question 3

Which TWO commands can be used to display the current SELinux mode?

Accepted Answer

sestatus. The `sestatus` command displays the current SELinux mode (enforcing, permissive, or disabled) along with other SELinux status information. The `getenforce` command specifically returns only the current SELinux mode as a string (Enforcing, Permissive, or Disabled). Both are standard tools for checking the SELinux operational state.

Answer

checkmodule

Answer

seinfo

Answer

setenforce

Question 4

Which THREE of the following are common steps to configure a system to automatically mount an NFS share at boot?

Accepted Answer

Ensure nfs-utils is installed. B is correct because the NFS client functionality in Red Hat Enterprise Linux is provided by the nfs-utils package. Without this package installed, the system lacks the necessary tools (such as mount.nfs and rpcbind) to mount NFS shares, making it impossible to configure automatic mounting at boot.

Answer

Run 'mount -a' after boot

Answer

Configure /etc/exports

Question 5

Which TWO files are essential in the /boot directory for the kernel to boot?

Accepted Answer

initramfs. The initramfs (initial RAM filesystem) is essential because it contains the necessary drivers and tools to mount the root filesystem before the kernel can take over. Without it, the kernel would not be able to access the storage device containing the root partition, especially when using filesystems or hardware that require kernel modules not built into the kernel itself.

Answer

fstab

Answer

grub.cfg

Answer

kernel

Question 6

Refer to the exhibit. An administrator needs to free up space in the /backup filesystem. Which of the following actions would be MOST effective?

Accepted Answer

Remove unnecessary files in /backup. The most direct way to free up space in the /backup filesystem is to remove unnecessary files stored there. This action immediately reclaims available space without altering the underlying logical volume or affecting other filesystems.

Answer

Increase the size of the logical volume

Answer

Delete old log files in /var/log

Answer

Use lvreduce to shrink the logical volume

Question 7

Refer to the exhibit. A web server must also accept HTTPS traffic on port 8443. Which command should the administrator run to permanently open this port?

Accepted Answer

firewall-cmd --add-port=8443/tcp --permanent && firewall-cmd --reload. It uses `--add-port=8443/tcp` to open a non-standard port (8443) for HTTPS traffic, applies the `--permanent` flag to persist the rule across reboots, and then runs `--reload` to activate the change immediately without restarting the firewall service. Without `--reload`, the permanent rule would not take effect until the next firewall reload or system restart.

Answer

firewall-cmd --add-service=8443/tcp --permanent

Answer

firewall-cmd --add-port=8443/tcp

Answer

firewall-cmd --add-port=8443/tcp --zone=public

Question 8

Refer to the exhibit. The SSH service has been running for 2 weeks. An administrator wants to restart the service without interrupting existing SSH connections. Which command should they use?

Accepted Answer

systemctl reload sshd. `systemctl reload sshd` sends a SIGHUP signal to the SSH daemon, instructing it to reload its configuration file without terminating existing connections. This is the standard method for applying configuration changes to services that support graceful reloads, such as sshd, which maintains persistent sessions by only re-reading its configuration and not restarting the process.

Answer

systemctl stop sshd; systemctl start sshd

Answer

kill -HUP 1234

Answer

systemctl restart sshd

Question 9

An administrator needs to ensure that the httpd service starts automatically after a system reboot and is set to start immediately without rebooting. Which command should be used?

Accepted Answer

systemctl enable --now httpd. `systemctl enable --now httpd` both creates the necessary symlinks to start the httpd service automatically at boot (enable) and starts the service immediately (--now) without requiring a reboot. This combines two operations into one command, satisfying both requirements in the question.

Answer

systemctl set-default httpd

Answer

systemctl add httpd

Answer

systemctl start --enable httpd

Question 10

An administrator has a logical volume 'lv_data' in a volume group 'vg_data' with a filesystem. The administrator needs to reduce the size of 'lv_data' by 2GB. Which sequence of commands should be performed?

Accepted Answer

umount, e2fsck -f, resize2fs, lvreduce. Reducing a logical volume with a filesystem requires a specific sequence: first unmount the filesystem to ensure no writes occur, then run e2fsck -f to force a filesystem check and ensure consistency, then use resize2fs to shrink the filesystem to the desired size, and finally lvreduce to shrink the logical volume itself. This order prevents data corruption by resizing the filesystem before the underlying block device.

Answer

lvreduce, resize2fs, e2fsck, umount

Answer

resize2fs, lvreduce, umount, e2fsck

Answer

umount, lvreduce, resize2fs, e2fsck

Question 11

A system administrator wants to allow incoming HTTPS traffic on the default zone of firewalld. Which command should be used?

Accepted Answer

firewall-cmd --add-service=https --permanent. The `--add-service=https` option adds the predefined HTTPS service (port 443/tcp) to the firewalld configuration. The `--permanent` flag ensures the rule persists across reboots. By default, the command applies to the default zone if no zone is specified, which matches the requirement to allow HTTPS traffic on the default zone.

Answer

firewall-cmd --add-port=443/tcp --zone=public --permanent

Answer

firewall-cmd --enable-service=https

Answer

firewall-cmd --add-rule=allow https

Question 12

An administrator wants to optimize system performance for a database workload. Which tool should be used to select a performance profile?

Accepted Answer

tuned-adm profile throughput-performance. C is correct because `tuned-adm profile throughput-performance` selects a Tuned performance profile optimized for high throughput, which is suitable for database workloads that benefit from increased I/O and network performance. Tuned is the systemd-based dynamic system tuning daemon in RHEL that adjusts kernel parameters, disk schedulers, and other settings based on the selected profile.

Answer

performance-tune --profile database

Answer

setroubleshoot

Answer

systemctl set-profile database

Question 13

An administrator needs to set up an automount point for NFS shares from server nfs.example.com:/exports/backup. The mount point should be /backup and should mount on access. Which configuration is correct?

Accepted Answer

Add to /etc/auto.master: /backup /etc/auto.backup and in /etc/auto.backup: backup -fstype=nfs4 nfs.example.com:/exports/backup. To automount the NFS share at exactly /backup, use a direct map: in /etc/auto.master add '/- /etc/auto.backup', and in /etc/auto.backup add '/backup -fstype=nfs4 nfs.example.com:/exports/backup'. Option C uses an indirect map, placing the export at /backup/backup, contradicting the requirement that the mount point be /backup.

Answer

Install autofs and create /etc/auto.master.d/backup.autofs with the same content

Answer

Use systemd-mount with automount options

Answer

Add an entry to /etc/fstab: nfs.example.com:/exports/backup /backup nfs4 defaults 0 0

Question 14

An administrator wants to view only the error messages from the kernel ring buffer since last boot. Which command should be used?

Accepted Answer

journalctl -k -p err. `journalctl -k -p err` filters the kernel messages (`-k`) from the systemd journal by priority level `err` (error), showing only error-level kernel messages since the last boot. This is the standard way to view kernel error messages in modern RHEL/CentOS systems using systemd-journald.

Answer

cat /var/log/kernel-errors

Answer

dmesg -p err

Answer

systemctl status kernel

Question 15

Which two commands correctly set the system to boot into a multi-user target (runlevel 3)?

Accepted Answer

systemctl set-default multi-user.target. `systemctl set-default multi-user.target` sets the default systemd target to multi-user.target, which corresponds to runlevel 3. This command changes the symlink at /etc/systemd/system/default.target to point to the specified target, ensuring the system boots into that target by default.

Answer

systemctl enable multi-user.target

Answer

systemctl default multi-user

Answer

systemctl set-default runlevel3.target