EX200 Practice Test 3 — 10 Questions

Question 1

A team wants to run a container as a non-root user inside the container for security. Which instruction should be included in the Containerfile?

Accepted Answer

USER. The USER instruction in a Containerfile (Dockerfile) sets the user name or UID to use when running the container and for any subsequent RUN, CMD, or ENTRYPOINT instructions. By default, containers run as root (UID 0), which poses a security risk. Using USER to switch to a non-root user (e.g., USER 1001) ensures the container process runs with reduced privileges, aligning with the principle of least privilege.

Answer

PODMAN_USER

Answer

ENV USER

Answer

RUN useradd

Question 2

A Red Hat Enterprise Linux 9 server has an LVM volume group 'vg01' that contains two physical volumes: /dev/sda2 and /dev/sdb1. After a reboot, the system fails to activate the volume group. The administrator runs 'pvdisplay' and sees one physical volume as 'unknown device'. What is the most likely cause?

Accepted Answer

The LVM filter in /etc/lvm/lvm.conf is excluding /dev/sdb1. The LVM filter in /etc/lvm/lvm.conf controls which devices LVM scans during activation. If the filter excludes /dev/sdb1, LVM will not recognize that physical volume, causing the volume group to fail activation. The 'unknown device' status indicates LVM cannot access the device metadata, not that the device is missing or corrupted.

Answer

The physical volume is corrupted and needs to be restored from backup

Answer

The filesystem on the logical volume has become corrupted, preventing LVM metadata access

Answer

The UUID of the physical volume has changed due to a disk replacement

Question 3

An administrator receives an alert that a process named 'apache2' is consuming excessive CPU. The administrator needs to identify the PID of the process and then change its priority to the lowest possible value (least favorable scheduling). Which sequence of commands should be used?

Accepted Answer

pidof apache2; renice -n 19 -p . `pidof apache2` retrieves the PID of the apache2 process, and `renice -n 19 -p ` sets the priority to the lowest possible (least favorable) scheduling value. In Linux, `renice` accepts nice values from -20 (highest priority) to 19 (lowest priority), so 19 is the correct value for the least favorable scheduling.

Answer

pidof apache2; renice -n 20 -p <PID>

Answer

ps -C apache2 -o pid=; renice -n -20 -p <PID>

Answer

ps aux | grep apache2; nice -n 19 <PID>

Question 4

You are managing a Red Hat Enterprise Linux 8 server that hosts backup scripts. A user named 'backup' (UID 1005) is a member of the 'backup' group. The directory /var/backups is owned by root:backup with permissions 775. The 'backup' user needs to create files in this directory. However, when the user attempts to create a file, they receive 'Permission denied'. You verify that 'backup' is indeed listed in the backup group in /etc/group. The user's current shell was started after their last login. Which of the following is the most likely cause and solution?

Accepted Answer

The user needs to log out and log back in to refresh their group membership.. The user 'backup' is already a member of the 'backup' group in /etc/group, but the current shell session was started before the group membership was added or refreshed. On Linux, group membership is determined at login time by the PAM modules; simply adding a user to a group does not affect already running processes. The user must log out and log back in (or start a new login shell) to acquire the new group membership via the initgroups() system call, which populates the process's supplementary group list.

Answer

The directory lacks the setgid bit; set it with 'chmod g+s /var/backups'.

Answer

The user's umask is too restrictive, preventing file creation. Change the umask to 002.

Answer

The user should use 'newgrp backup' to switch to the backup group temporarily.

Question 5

Refer to the exhibit. An administrator needs to create a new 5GB filesystem for /var/log. Which step is required?

Accepted Answer

Add /dev/sdc as a physical volume, extend vg00, create a logical volume, and format. To create a new filesystem for /var/log using available space on /dev/sdc, the disk must first be added as a physical volume (pvcreate), then added to the existing volume group vg00 (vgextend). After extending the VG, a new logical volume can be created (lvcreate) and formatted with a filesystem (e.g., mkfs.xfs). This approach leverages LVM's flexibility to allocate space from multiple physical volumes without requiring a separate volume group or partition manipulation.

Answer

Create a new partition on /dev/sdc and format with xfs

Answer

Shrink /home to free space in vg00 and create a new LV

Answer

Create a new volume group using /dev/sdb

Question 6

A company needs to create a user account for a temporary contractor who will work for exactly 90 days. The account must be automatically disabled after 90 days. Which command should the administrator use?

Accepted Answer

useradd -e $(date -d '+90 days' +%Y-%m-%d) contractor. The `-e` (expiration date) option sets the date on which the user account will be disabled. Using `$(date -d '+90 days' +%Y-%m-%d)` dynamically calculates the exact date 90 days from today in YYYY-MM-DD format, which meets the requirement for automatic disable after exactly 90 days.

Answer

useradd -f 90 contractor

Answer

useradd -e 90 contractor

Answer

useradd -f 90 -e 0 contractor

Question 7

A user named jdoe is receiving 'Permission denied' errors when trying to access a file owned by root with permissions 644. The user is a member of the root group. What is the most likely cause?

Accepted Answer

The directory containing the file lacks execute permission for the group or others.. The file has permissions 644, meaning the owner (root) has read/write, and the group (root) and others have read-only access. Since jdoe is a member of the root group, the file's group read permission should allow access. However, to traverse a directory and access any file within it, the user needs execute (x) permission on that directory. If the directory lacks execute for the group or others, jdoe will get 'Permission denied' even if the file permissions are correct.

Answer

The file's group owner is not root.

Answer

The file's read permission is not granted to the root group.

Answer

The user needs to be added to the root group again.

Question 8

An administrator needs to create a network bond interface 'bond0' with two slave interfaces 'eth0' and 'eth1' using active-backup mode. Which set of commands is correct?

Accepted Answer

nmcli con add type bond ifname bond0 mode active-backup; nmcli con add type bond-slave ifname eth0 master bond0; nmcli con add type bond-slave ifname eth1 master bond0. The commands create a bond interface with active-backup mode using nmcli. First, `nmcli con add type bond ifname bond0 mode active-backup` creates the bond with the required mode. Then, `nmcli con add type bond-slave ifname eth0 master bond0` and similarly for eth1 add the slave interfaces. This is the correct set of commands that fulfills the requirement. Option A uses an alternative syntax but does not set the mode. Option B involves manual editing, and option C uses teamd, which is for teaming, not bonding.

Answer

nmcli con add type bond ifname bond0; nmcli con add type ethernet ifname eth0 master bond0 slave-type bond

Answer

Edit /etc/sysconfig/network-scripts/ifcfg-bond0 and ifcfg-eth0 manually

Answer

teamd -d -c '{"device":"bond0","runner":{"name":"activebackup"},"ports":{"eth0":{},"eth1":{}}}'

Question 9

Refer to the exhibit. An administrator needs to create a 1.2 TiB logical volume named 'data' in volume group 'myvg' and mount it persistently at /data. Which sequence of commands should be used?

Accepted Answer

lvcreate -L 1.2T -n data myvg
mkfs.xfs /dev/myvg/data
echo '/dev/myvg/data /data xfs defaults 0 0' >> /etc/fstab
mount -a. It creates a logical volume of exactly 1.2 TiB using the valid -L 1.2T size specification. LVM's -L option accepts floating-point values with suffixes like T for TiB. The volume is formatted with XFS (default for RHEL 8+), a correct fstab entry is added with /dev/myvg/data, and mount -a mounts it persistently. Option D uses 1200G, which yields approximately 1.17 TiB, not the required 1.2 TiB.

Answer

lvcreate -L 1.2T -n data myvg
mkfs.ext4 /dev/myvg/data
echo '/dev/myvg/data /data ext4 defaults 0 0' >> /etc/fstab
mount -a

Answer

lvcreate -l 100%FREE -n data myvg
mkfs.xfs /dev/myvg/data
echo '/dev/mapper/myvg-data /data xfs defaults 0 0' >> /etc/fstab
mount -a

Answer

lvcreate -L 1200G -n data myvg
mkfs.ext4 /dev/myvg/data
echo '/dev/myvg/data /data ext4 defaults 0 0' >> /etc/fstab
mount -a

Question 10

An administrator writes a script that uses the 'set -e' option at the top. What is the primary effect of this option?

Accepted Answer

It exits the script immediately if a command fails. The 'set -e' option instructs the shell to exit immediately if any command or pipeline returns a non-zero exit status (i.e., fails). This is commonly used in scripts to prevent execution from continuing after an error, which could lead to unpredictable behavior or data corruption. It does not affect variable handling, command printing, or debug verbosity.

Answer

It treats unset variables as an error

Answer

It prints each command before execution

Answer

It enables debug mode with verbose output