EX200 Deploy, configure, and maintain systems — 40 Questions

Question 1

A system administrator needs to ensure that a specific kernel module 'usb_storage' is not loaded automatically during boot on a RHEL 9 system. Which configuration file should be modified to blacklist this module?

Accepted Answer

Add 'blacklist usb_storage' to /etc/modprobe.d/blacklist.conf. Option C is correct because on RHEL 9, the recommended way to prevent a kernel module from loading automatically is to add a 'blacklist' directive in a file under /etc/modprobe.d/. The file /etc/modprobe.d/blacklist.conf is a conventional location for such blacklist entries. When modprobe processes this file, it will ignore the specified module during boot and when loading modules manually, effectively preventing usb_storage from being loaded.

Answer

Add 'blacklist usb_storage' to /etc/modules-load.d/usb_storage.conf

Answer

Add 'install usb_storage /bin/false' to /etc/sysconfig/modules/

Answer

Add 'blacklist usb_storage' to /etc/init.d/rc.local

Question 2

A Red Hat Enterprise Linux 9 system has a logical volume 'lv_data' in the volume group 'vg_data' that needs to be resized from 10G to 15G. The underlying physical volumes have enough free space. Which sequence of commands correctly resizes the logical volume and the ext4 filesystem?

Accepted Answer

lvextend -L 15G /dev/vg_data/lv_data; resize2fs /dev/vg_data/lv_data. Option A is correct because to resize an ext4 filesystem on a logical volume, you must first extend the logical volume with `lvextend -L 15G /dev/vg_data/lv_data` to allocate the additional 5G from the volume group, then use `resize2fs /dev/vg_data/lv_data` to grow the filesystem to fill the enlarged block device. This order ensures the underlying block device has sufficient capacity before the filesystem resize operation.

Answer

resize2fs /dev/vg_data/lv_data; lvextend -L 15G /dev/vg_data/lv_data

Answer

lvextend -L 15G /dev/vg_data/lv_data; xfs_growfs /dev/vg_data/lv_data

Answer

lvreduce -L 15G /dev/vg_data/lv_data; resize2fs /dev/vg_data/lv_data

Question 3

A technician needs to configure a static IPv4 address on a RHEL 9 network interface 'enp1s0' using NetworkManager. Which command should be used to set the IP address?

Accepted Answer

nmcli connection modify enp1s0 ipv4.addresses 192.168.1.100/24. Option A is correct because `nmcli connection modify enp1s0 ipv4.addresses 192.168.1.100/24` is the proper NetworkManager command to set a static IPv4 address on a RHEL 9 interface. This command modifies the connection profile for 'enp1s0' by setting the `ipv4.addresses` property to the specified address and prefix length, which is the standard method for persistent static IP configuration via NetworkManager.

Answer

nmtui edit enp1s0 --ipv4 192.168.1.100/24

Answer

ip addr add 192.168.1.100/24 dev enp1s0

Answer

ifconfig enp1s0 192.168.1.100 netmask 255.255.255.0

Question 4

A system administrator is tasked with configuring a RHEL 9 system to automatically mount an NFS share from 192.168.1.10:/export/data on /mnt/data at boot. Which entry in /etc/fstab is correct?

Accepted Answer

192.168.1.10:/export/data /mnt/data nfs4 defaults 0 0. Option C is correct because the /etc/fstab entry for an NFS mount requires the remote server and export path in the format server:/export, followed by the local mount point, the filesystem type (nfs4 for NFSv4), mount options, dump flag, and fsck order. This matches the standard NFS fstab syntax for automatic mounting at boot.

Answer

192.168.1.10 /export/data /mnt/data nfs4 defaults 0 0

Answer

/mnt/data 192.168.1.10:/export/data nfs4 defaults 0 0

Answer

192.168.1.10:/export/data /mnt/data nfs defaults 0 0

Question 5

A system administrator notices that a RHEL 9 server's /var/log/messages is filling up the /var partition. The administrator wants to ensure log rotation runs daily and keeps 4 weeks of logs. Which configuration file should be modified?

Accepted Answer

/etc/logrotate.d/syslog. Option B is correct because /etc/logrotate.d/syslog is the configuration file that controls log rotation for system log files such as /var/log/messages. By modifying this file, the administrator can set the rotation frequency to daily and specify the number of weeks (e.g., rotate 28 for 4 weeks) to retain logs, directly addressing the requirement.

Answer

/etc/systemd/journald.conf

Answer

/etc/rsyslog.conf

Answer

/etc/cron.daily/logrotate

Question 6

A user reports that they cannot log in to a RHEL 9 system. The administrator checks /etc/passwd and finds the user's shell is set to /sbin/nologin. What is the most likely cause?

Accepted Answer

The user account is intentionally disabled for login.. The /sbin/nologin shell is a valid shell entry that, when set as a user's login shell, prevents interactive login by immediately exiting with a message that the account is not available. This is a standard method for disabling login for system accounts (e.g., daemon, bin) or intentionally disabling a user account while keeping the account and its files intact. Option D correctly identifies that the user account is intentionally disabled for login.

Answer

The SSH service is not running.

Answer

The user account has been locked by pam_tally2.

Answer

The user's password has expired.

Question 7

An administrator wants to install a package 'httpd' but only if it is available in the configured repositories. Which command should be used to check if the package exists?

Accepted Answer

dnf list available httpd. Option C is correct because `dnf list available httpd` queries the configured DNF repositories and displays the package only if it exists in them. This command checks availability without installing, which matches the requirement to verify the package is present in the repositories before proceeding.

Answer

rpm -q httpd

Answer

dnf search httpd

Answer

dnf install httpd

Question 8

A RHEL 9 system has a second disk /dev/sdb that needs to be partitioned with a single partition using all space, formatted with XFS, and mounted persistently at /data. The administrator uses fdisk to create the partition /dev/sdb1. Which filesystem creation command should be used?

Accepted Answer

mkfs.xfs /dev/sdb1. The correct command is mkfs.xfs /dev/sdb1 because the question specifies that the partition must be formatted with XFS. The mkfs.xfs command is the dedicated tool for creating an XFS filesystem on a block device. It directly invokes the mkfs.xfs utility, which writes the XFS superblock and metadata structures to the partition.

Answer

mke2fs /dev/sdb1

Answer

mkfs -t ext4 /dev/sdb1

Answer

mkfs.ext4 /dev/sdb1

Question 9

Which TWO statements are true about systemd services in RHEL 9? (Choose exactly two.)

Accepted Answer

'systemctl list-units --type=service' lists all service units.. Option A is correct because 'systemctl list-units --type=service' filters the output to show only service units, which are the primary unit type for managing daemons and background processes. Option C is correct because 'systemctl status' displays the current state of a unit, including whether it is active (running), inactive (stopped), or in another state like failed.

Answer

'systemctl enable' starts the service immediately.

Answer

'systemctl mask' disables a service but allows manual start.

Answer

'systemctl disable' stops the service immediately.

Question 10

Which THREE are valid methods to configure network bonding in RHEL 9? (Choose exactly three.)

Accepted Answer

Using a configuration file in /etc/NetworkManager/system-connections/.. Option A is correct because in RHEL 9, NetworkManager stores connection profiles in `/etc/NetworkManager/system-connections/`. You can manually create a bond configuration file in this directory with the proper key-value pairs (e.g., `type=bond`, `bond.options=mode=1,miimon=100`), and NetworkManager will read it on restart or reload. This is a valid method for configuring network bonding.

Answer

Using the teamd service.

Answer

Editing /etc/sysconfig/network-scripts/ifcfg-bond0 directly.

Question 11

Which TWO are correct ways to check the SELinux context of a file named 'test.txt'? (Choose exactly two.)

Accepted Answer

ls -Z test.txt. Option A is correct because `ls -Z` displays the SELinux security context of files, including user, role, type, and sensitivity level. The `-Z` option is specifically designed to show SELinux context information for files and processes.

Answer

ls -l test.txt

Answer

sestatus

Answer

getenforce

Question 12

Refer to the exhibit. The service 'example.service' is created but fails to start. The administrator runs 'systemctl start example.service' and gets no output, but 'systemctl status example.service' shows 'active (exited)'. What is the most likely cause?

Accepted Answer

The script /usr/local/bin/example.sh exits immediately.. When a service unit is configured with `Type=oneshot` (or the default `Type=simple` with a script that exits quickly), systemd reports the service as `active (exited)` after the main process finishes. The administrator sees no error output because the command `systemctl start` succeeded in launching the process, but the process itself (the script `/usr/local/bin/example.sh`) exits immediately, which is expected behavior for a oneshot service. The service is considered 'active' because it ran and exited cleanly, not because it remains running.

Answer

The Restart=on-failure directive is misconfigured.

Answer

The network.target dependency is not met.

Answer

The administrator forgot to run systemctl daemon-reload after starting.

Question 13

Refer to the exhibit. The administrator wants to add an additional 5GB to the /mnt/data filesystem. There is no unpartitioned space on /dev/sdb. Which is the correct procedure?

Accepted Answer

Use fdisk to delete and recreate /dev/sdb1 with larger size, run partprobe, then xfs_growfs /mnt/data.. Option C is correct because the filesystem on /mnt/data is XFS (as shown in the exhibit), and XFS cannot be shrunk; it can only be grown. Since there is no unpartitioned space on /dev/sdb, the partition itself must be resized. The correct procedure is to delete and recreate the partition with a larger size using fdisk, inform the kernel of the change with partprobe, and then grow the XFS filesystem with xfs_growfs /mnt/data.

Answer

Use resize2fs /dev/sdb1 to expand filesystem.

Answer

Add a new disk, create a physical volume, extend volume group, and extend logical volume.

Answer

Use fdisk to delete and recreate /dev/sdb1 with larger size, then mount.

Question 14

A company has a RHEL 9 server that hosts a critical application. The server has two network interfaces: enp1s0 (192.168.1.100/24) and enp2s0 (10.0.0.100/24). The default gateway is 192.168.1.1. The application listens on a TCP port 8080 and should be accessible from both networks. Recently, the administrator noticed that clients on the 10.0.0.0/24 network can ping the server's 10.0.0.100 address but cannot connect to port 8080. Clients on 192.168.1.0/24 can connect fine. The firewall is configured with the default zone (public) and the service 'http' is allowed, but port 8080 is not specifically allowed. The administrator checks 'firewall-cmd --list-all' and sees that only services 'ssh' and 'http' are listed. The application is running and listening on 0.0.0.0:8080. What is the most likely cause and the correct course of action?

Accepted Answer

Add a firewall rule to open TCP port 8080 in the public zone using 'firewall-cmd --add-port=8080/tcp --permanent' and reload.. The firewall is blocking incoming connections to port 8080 because only services 'ssh' (port 22) and 'http' (port 80) are allowed in the public zone. Since the application listens on 0.0.0.0:8080, it is reachable from both networks at the IP level, but the firewall drops packets destined for port 8080. Adding a permanent rule to open TCP port 8080 and reloading the firewall configuration resolves the issue.

Answer

Disable SELinux to allow the application to accept connections.

Answer

Change the application to listen only on the 10.0.0.100 interface.

Answer

Add a static route for the 10.0.0.0/24 network via the 10.0.0.1 gateway.

Question 15

A system administrator needs to ensure that a web server running Apache httpd starts automatically after a system reboot. Which command should the administrator use to enable the httpd service?

Accepted Answer

systemctl enable httpd. Option D is correct because `systemctl enable httpd` creates the necessary symlinks in the systemd unit configuration directories (e.g., `/etc/systemd/system/multi-user.target.wants/`) to ensure the httpd service starts automatically at boot. This is the standard method for enabling a service in a Red Hat Enterprise Linux 8/9 environment using systemd.

Answer

systemctl daemon-reload

Answer

systemctl start httpd

Answer

systemctl reenable httpd

Question 16

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

Accepted Answer

getenforce. The `getenforce` command (option C) displays the current SELinux mode as either Enforcing, Permissive, or Disabled. The `sestatus` command (option D) provides a detailed status report including the current mode, the loaded policy, and the mode from the configuration file. Both are standard tools for querying the SELinux operational state.

Answer

setenforce

Answer

ausearch

Answer

semanage

Question 17

An administrator runs 'df -h' and sees the output above. The /data partition is nearly full. Which command will help identify the largest files in /data?

Accepted Answer

du -sh /data/*. Option D is correct because 'du -sh /data/*' calculates the total disk usage of each top-level item (files and directories) within /data, showing human-readable sizes. The asterisk expands to all immediate children, allowing the administrator to identify which specific files or directories consume the most space, which is exactly what is needed when /data is nearly full.

Answer

du -sch /data/*

Answer

du -sh /data

Answer

du -h --max-depth=1 /data

Question 18

Order the steps to configure SELinux to allow Apache to read files in a custom directory /webcontent.

Question 19

Match each SELinux mode to its behavior.

Question 20

An administrator needs to configure a service to start automatically at boot and also start it immediately without rebooting. Which single command accomplishes both tasks?

Accepted Answer

systemctl enable --now httpd.service. Option C is correct because `systemctl enable --now httpd.service` combines the `enable` action (creating symlinks for automatic start at boot) with the `start` action (immediately launching the service) in a single command. This is the precise method in systemd to achieve both goals without rebooting.

Answer

systemctl start httpd.service

Answer

systemctl enable httpd.service

Answer

systemctl reenable httpd.service