EX200 Practice Test 11 — 15 Questions

Question 1

A system administrator is setting up storage for a new application server. The application requires two separate filesystems: one for the database (needs to be at least 10GiB) and one for logs (needs at least 5GiB). The server has a single 20GiB disk /dev/sda. The administrator plans to use LVM and a single volume group 'vg_app'. They create physical volume on /dev/sda, create the volume group, and then create two logical volumes: 'lv_db' of 10GiB and 'lv_logs' of 5GiB. They format lv_db as ext4 and lv_logs as xfs, and mount them at /db and /logs respectively. After rebooting, the system fails to mount /logs. What is the most likely cause?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

The /logs entry is missing from /etc/fstab.. The most likely cause is that the /logs entry is missing from /etc/fstab. After reboot, the system relies on /etc/fstab to mount filesystems automatically. Since the administrator created and mounted the filesystem manually, but did not add an entry for /logs in /etc/fstab, the mount fails on reboot. The database mount may succeed if it was added, but the logs mount fails due to the missing fstab entry.

Answer

The logical volume 'lv_logs' overlaps with 'lv_db'.

Answer

The physical volume /dev/sda is not recognized by LVM after reboot.

Answer

The volume group 'vg_app' is not automatically activated.

Question 2

A complex script uses 'trap' to handle signals. The admin writes 'trap '' SIGINT' to ignore Ctrl+C, but later in the script they want to re-enable the default behavior. Which command restores the default behavior for SIGINT?

Accepted Answer

trap - SIGINT. `trap - SIGINT` resets the signal handler for SIGINT to its default behavior. The `trap '' SIGINT` command sets an empty action, which ignores the signal; using `trap - signal` removes that custom handler and restores the default action (typically terminating the process).

Answer

trap : SIGINT

Answer

trap 2

Answer

trap SIGINT

Question 3

A system administrator wants to run a container as a systemd service that restarts automatically after a system reboot. Which approach follows Red Hat best practices?

Accepted Answer

Use 'podman generate systemd --new --name mycontainer' and enable the generated service.. `podman generate systemd --new --name mycontainer` creates a systemd unit file that defines the container as a transient service with `Restart=always` and `WantedBy=multi-user.target`, ensuring the container starts automatically after a reboot. This approach aligns with Red Hat best practices for managing containers as systemd services, leveraging systemd's native dependency and restart capabilities rather than relying on legacy or non-standard methods.

Answer

Create a cron job that checks if the container is running and starts it if not.

Answer

Create a sysvinit script that calls podman commands.

Answer

Add 'podman run ...' to /etc/rc.local.

Question 4

Refer to the exhibit. An administrator tries to mount the partition /dev/sdc1 and gets a superblock error. What is the most likely cause?

Accepted Answer

The filesystem has not been created; mkfs.xfs was not run. The superblock error indicates that the kernel cannot read the filesystem metadata at the start of the partition. This most commonly occurs when no filesystem has been created on the partition — i.e., mkfs.xfs was never run on /dev/sdc1. Without a valid filesystem superblock, the mount command fails with a 'wrong fs type, bad option, bad superblock' message.

Answer

The filesystem is not recognized; need to install xfsprogs

Answer

The partition table is corrupted

Answer

The mount point /mnt/backup does not exist

Question 5

Refer to the exhibit. Which command will ensure cron jobs run automatically at system boot?

Accepted Answer

systemctl enable crond. The `systemctl enable crond` command creates the necessary symlinks in the systemd unit configuration to ensure the `crond` service starts automatically at boot. This is the correct method to enable a service for automatic startup in a systemd-based Red Hat Enterprise Linux system.

Answer

systemctl reenable crond

Answer

systemctl start crond

Answer

systemctl unmask crond

Question 6

A systems administrator needs to list all currently defined firewall rules in firewalld, including rules for all zones. Which TWO commands can be used to accomplish this? (Choose exactly two.)

Accepted Answer

firewall-cmd --list-all-zones. `firewall-cmd --list-all-zones` displays the firewall rules for every zone in firewalld, including all default and custom zones, satisfying the requirement to list rules for all zones. Option E is incorrect because `firewall-cmd --list-all` only shows rules for the default zone, not all zones. The other options are incorrect: `iptables -L` shows raw kernel rules that may not reflect firewalld's configuration, `systemctl status firewalld` checks the service status, and `firewall-cmd --get-default-zone` shows only the default zone name, not rules.

Answer

iptables -L

Answer

systemctl status firewalld

Answer

firewall-cmd --get-default-zone

Answer

firewall-cmd --list-all

Question 7

Which command sets the password maximum age for user 'bob' to 30 days?

Accepted Answer

chage -M 30 bob. Both `chage -M 30 bob` and `passwd -x 30 bob` are valid commands to set the maximum password age for user 'bob' to 30 days. `chage -M` is the commonly used and RHCSA-recommended tool for password aging, but `passwd -x` also works on Red Hat systems. Option C (`usermod -e`) sets account expiration, not password maximum age. Option D (`chage -W`) sets the warning period before expiry.

Answer

usermod -e 30 bob

Answer

chage -W 30 bob

Question 8

A technician is configuring a new Red Hat Enterprise Linux 9 server with multiple disks. They need to create a RAID 1 array using /dev/sda and /dev/sdb for the /boot partition. Which tool can create the RAID array and enable booting from it?

Accepted Answer

Use mdadm to create a RAID1 device and install GRUB on both disks. Mdadm is the standard Linux tool for creating software RAID arrays, including RAID 1 (mirroring). For the /boot partition, which must be readable by the bootloader, GRUB must be installed on both disks in the RAID 1 array to ensure bootability if one disk fails. mdadm creates the RAID device, and GRUB can then be installed on each disk's MBR or GPT partition.

Answer

Use parted to create a RAID array directly by specifying the RAID level

Answer

Use fdisk to create a RAID partition and then format with ext4

Answer

Use LVM to create a mirrored logical volume for /boot

Question 9

Which TWO of the following are valid ways to make a shell script executable?

Accepted Answer

chmod 755 script.sh. Options B and D are both valid ways to make a shell script executable. Option B uses numeric mode to set execute permission for the owner, while option D uses symbolic mode to add execute for the owner only. Option E is also valid but is not one of the two answers required by the question.

Answer

bash script.sh

Answer

. script.sh

Answer

chmod +x script.sh

Question 10

A developer is running Podman as a non-root user on a Red Hat Enterprise Linux 8 system. The developer successfully runs a container, but notices that after logging out of the SSH session, the container stops. The developer wants the container to continue running even after disconnecting from the SSH session. The container is a simple web server that listens on port 8080. The developer has already enabled lingering for the user account using 'loginctl enable-linger'. However, the container still stops upon logout. What additional step should the developer take to ensure the container persists after logout?

Accepted Answer

Create a systemd user service by running 'podman generate systemd --new --name mywebcontainer' and then enable and start the service with 'systemctl --user enable --now container-mywebcontainer.service'. Even with lingering enabled, a container started directly via `podman run` is tied to the user's login session and will be terminated when the session ends. To make the container persist independently of the SSH session, it must be managed as a systemd user service. The `podman generate systemd --new` command creates a systemd unit file that can be enabled with `systemctl --user`, ensuring the container starts automatically and continues running after logout.

Answer

Add the --restart=always flag to the podman run command

Answer

Use podman run --detach to run the container in the background

Answer

Use podman run -d to run the container in detached mode

Question 11

Which TWO commands can change the primary group of an existing user?

Accepted Answer

usermod -aG. None of the listed commands change the primary group of an existing user. The correct commands are `usermod -g` to change the primary group directly, or `groupmod -g` after ensuring the user is the only member of the group.

Answer

vigr

Answer

groupmems -a

Answer

useradd -G

Question 12

Which three fields are present in every /etc/fstab entry? (Choose three.)

Accepted Answer

Mount point. Every /etc/fstab entry consists of six whitespace-separated fields: device, mount point, filesystem type, options, dump, and pass. Although dump and pass can be omitted and default to 0, the dump field is considered present in every entry due to its default value. The question asks for three fields that are present in every entry; these include the mount point (A), device (B), and dump field (C). The filesystem type (D) is also present, but the question requires exactly three choices, and the dump field is often overlooked. UUID (E) is not a separate field; it is a method to specify the device.

Answer

Filesystem type

Answer

UUID

Question 13

During boot, a server fails to mount an NFS filesystem listed in /etc/fstab. Which troubleshooting step should be taken first to isolate the issue?

Accepted Answer

Check the status of remote-fs.target with 'systemctl status remote-fs.target'. When an NFS filesystem fails to mount during boot, the first step is to check whether the remote-fs.target unit is active. This target is responsible for triggering the mounting of all remote filesystems (including NFS) after the network is available. If remote-fs.target is not active or has failed, the NFS mount will not be attempted, and troubleshooting should start here before investigating the NFS share itself.

Answer

Check the status of nfs-client.target with 'systemctl status nfs-client.target'

Answer

Try to manually mount the NFS share with 'mount /mnt/nfs'

Answer

View kernel messages with 'dmesg | grep -i nfs'

Question 14

A system has a logical volume that is thinly provisioned. The thin pool has a size of 100GB and the thin volume has a virtual size of 500GB. The administrator notices that the thin pool has only 5GB of data written so far. Which command will display the current data usage of the thin volume?

Accepted Answer

lvs -o lv_name,data_percent. The `lvs -o lv_name,data_percent` command specifically displays the percentage of the thin pool that has been consumed by the thinly provisioned logical volume. For thin volumes, the `data_percent` field reports the actual data usage relative to the thin pool's capacity, which is exactly what the administrator needs to see the current 5GB usage against the 100GB pool.

Answer

df -h /dev/mapper/vg01-thinvol

Answer

lsblk /dev/mapper/vg01-thinvol

Answer

lvdisplay /dev/vg01/thinvol

Question 15

Which command can be used to create a logical volume using all available free space in a volume group?

Accepted Answer

lvcreate -l 100%FREE -n lvdata vgdata. The `-l 100%FREE` flag allocates all unallocated physical extents in the volume group, which is the precise way to use all available free space. Option D (`-l 100%VG`) is incorrect because it attempts to allocate 100% of the volume group's extents, including those already used by other logical volumes, causing the command to fail if any extents are already allocated. Therefore, only option B is correct.

Answer

lvcreate --size 20G vgdata lvdata

Answer

lvcreate -L 20G -n lvdata vgdata

Answer

lvcreate -l 100%VG -n lvdata vgdata

Answer

lvcreate -L 100%FREE -n lvdata vgdata