EX200 Practice Test 29 — 15 Questions

Question 1

On a default Red Hat Enterprise Linux 8 installation, which THREE tools or files can be used to configure time synchronization?

Accepted Answer

chronyc. On a default Red Hat Enterprise Linux 8 installation, `chronyd` is the default NTP daemon, and its configuration file is `/etc/chrony.conf`. The `chronyc` command is the command-line interface for interacting with the `chronyd` daemon, allowing you to monitor and adjust time synchronization. `timedatectl` is the systemd-based tool for managing system time and date settings, including enabling NTP synchronization via `chronyd`.

Answer

ntpq

Answer

/etc/ntp.conf

Question 2

A system administrator wants to allow user 'jdoe' to execute any command as root via sudo without being prompted for a password, but only from the host 'client1.example.com'. Which sudoers rule achieves this?

Accepted Answer

jdoe client1.example.com=(root) NOPASSWD: ALL. The sudoers rule 'jdoe client1.example.com=(root) NOPASSWD: ALL' specifies the user 'jdoe', the host 'client1.example.com' as the source host from which the command is run, the target user '(root)', the NOPASSWD tag to skip password authentication, and the command 'ALL' to allow any command. This matches the requirement exactly: passwordless root access restricted to a specific client host.

Answer

jdoe client1.example.com=(root) ALL

Answer

jdoe ALL=(root) NOPASSWD: ALL

Answer

jdoe ALL=(root) ALL

Question 3

An administrator needs to mount the backup filesystem with the ‘exec’ option temporarily for a one-time script. Which command will remount the filesystem with exec without unmounting?

Accepted Answer

mount -o exec,remount /dev/sdc1 /mnt/backup. Both options B and C are valid commands to remount a filesystem with the exec option without unmounting. Option B specifies both the device and mount point, which is accepted by the mount command when using the remount option. Option C uses only the mount point, which is also sufficient. The remount option allows changing mount options on a live filesystem. Options A and D are invalid: A unmounts and remounts, which is not a single remount operation and could cause issues; D attempts to remount all filesystems with exec, which may not apply correctly and does not target the specific filesystem.

Answer

umount /mnt/backup && mount /mnt/backup

Answer

mount -a -o exec

Question 4

An administrator needs to pull a container image from a private registry at registry.example.com:5000. The registry requires authentication. Which command should be used first?

Accepted Answer

podman login registry.example.com:5000. `podman login` authenticates the user to the specified private registry (registry.example.com:5000) before any pull or push operation. Without prior authentication, Podman cannot access the registry's content, and the pull command will fail with an authentication error.

Answer

podman tag registry.example.com:5000/myimage

Answer

podman images

Answer

podman pull registry.example.com:5000/myimage

Question 5

A user reports that they cannot use the 'systemctl' command to manage services. The user is part of the 'wheel' group. Which configuration change is required to allow this?

Accepted Answer

Ensure /etc/polkit-1/rules.d/10-admin.rules includes an admin rule for the wheel group. The 'systemctl' command requires PolicyKit authorization for non-root users to manage systemd services. The correct configuration is to add a PolicyKit rule in /etc/polkit-1/rules.d/10-admin.rules that grants the 'wheel' group administrative privileges, allowing them to invoke systemctl without a password or with appropriate authentication.

Answer

Set the 'permissive' mode for systemd via systemd.conf

Answer

Add the user to the 'systemd-journal' group

Answer

Add the user to /etc/sudoers with 'ALL ALL=(ALL) ALL'

Question 6

A system administrator is managing a Red Hat Enterprise Linux 9 web server running Apache httpd. The server hosts a custom application that stores its files in /var/www/custom. The administrator has set ownership to apache:apache and file permissions to 755. However, when users access the web application, they receive a 'Forbidden' error. The httpd service is running, and SELinux is in enforcing mode. The administrator checks the SELinux context of the /var/www/custom directory and sees 'unconfined_u:object_r:default_t:s0'. What should the administrator do to resolve the issue without disabling SELinux?

Accepted Answer

Use semanage fcontext to set the SELinux type to httpd_sys_content_t and run restorecon. The directory /var/www/custom has the SELinux type default_t, which the httpd_t domain is not permitted to read. Apache runs confined by SELinux, so even with correct Unix ownership and permissions, the kernel blocks access and returns 'Forbidden'. The correct fix is to persistently label the directory with httpd_sys_content_t using semanage fcontext, then apply it with restorecon. This preserves SELinux enforcement while granting httpd the access it needs.

Answer

Set SELinux to permissive mode

Answer

Use chcon to set the SELinux type to httpd_sys_content_t

Answer

Add the apache user to the group that owns the directory

Question 7

Match each log file to its typical content.

Accepted Answer

/var/log/messages: General system messages and events. These log files are commonly monitored by sysadmins. Correct matches: /var/log/messages for general messages, /var/log/secure for authentication, /var/log/maillog for mail, /var/log/cron for cron jobs. Common confusions involve swapping secure and maillog.

Answer

/var/log/messages: Authentication and security-related messages

Answer

/var/log/secure: Mail server logs

Question 8

A technician runs 'mkfs.xfs /dev/sdb1' and later mounts it. The file system is reported as having a block size of 1024 bytes. What is the most likely reason?

Accepted Answer

The partition size is less than 1GB, so mkfs.xfs automatically used a 1024-byte block size.. Mkfs.xfs automatically selects a 1024-byte block size when the underlying partition is smaller than 1 GB. This is a built-in heuristic in the XFS filesystem to optimize metadata overhead and space utilization on small volumes. The technician did not specify a block size, so the tool applied this default behavior based on partition size.

Answer

The administrator used the -b size=1024 option.

Answer

The block size setting was ignored due to a kernel limitation.

Answer

The default block size for XFS is 1024 bytes.

Question 9

A file server is experiencing slow write performance. The admin suspects the filesystem is nearly full. Which command should be used to check disk usage per partition?

Accepted Answer

df -h. The `df -h` command displays disk space usage for all mounted filesystems in human-readable format (e.g., GB, MB). This directly answers the admin's need to check per-partition usage and identify if a filesystem is nearly full, which can cause slow write performance due to lack of free space.

Answer

df -i

Answer

du -h --max-depth=1 /

Answer

du -sh /

Question 10

After a system crash, an administrator needs to review logs from the previous boot. Which command shows only logs from the boot before the current one?

Accepted Answer

journalctl -b -1. The `journalctl -b -1` command shows logs from the previous boot by using the `-b` (boot) option with an offset of `-1`, which refers to the boot session immediately before the current one. This is the correct way to access historical boot logs in systems using systemd-journald, as the journal retains logs from multiple boots by default.

Answer

dmesg -b -1

Answer

cat /var/log/boot.log

Answer

journalctl -b 0

Question 11

An administrator wants to modify the default expiration settings for new user passwords. Which file should be modified?

Accepted Answer

/etc/login.defs. The /etc/login.defs file contains default settings for user account creation, including password aging parameters such as PASS_MAX_DAYS, PASS_MIN_DAYS, and PASS_WARN_AGE. Modifying this file changes the default expiration settings for new user passwords system-wide, as these values are applied when a user is created via useradd or similar tools.

Answer

/etc/shadow

Answer

/etc/pam.d/passwd

Answer

/etc/security/pwquality.conf

Question 12

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 13

Which TWO commands can be used to create a physical volume for LVM? (Choose exactly two.)

Accepted Answer

pvcreate /dev/sdb1. The `pvcreate` command initializes a block device (such as a partition or an entire disk) for use as a physical volume in LVM. Option B targets a partition `/dev/sdb1`, and option C targets the whole disk `/dev/sdb` — both are valid devices that can be initialized as physical volumes, as LVM can operate on either.

Answer

mkfs.ext4

Answer

lvcreate

Answer

vgcreate

Question 14

A system administrator receives reports that a web server service (httpd) fails to start after a reboot. The administrator checks the service status and sees it is disabled. Which of the following is the most appropriate command to ensure the service starts automatically on future reboots?

Accepted Answer

systemctl enable httpd. The `systemctl enable httpd` command creates the necessary symlinks in the systemd unit configuration directory (typically `/etc/systemd/system/multi-user.target.wants/`) to ensure the httpd service starts automatically at boot. Since the service is disabled after reboot, enabling it is the correct action to set it to start on future reboots.

Answer

systemctl start httpd

Answer

systemctl restart httpd

Answer

systemctl daemon-reload

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. Option C, `systemctl set-default multi-user.target`, is correct because it changes the default boot target by creating the symlink `/etc/systemd/system/default.target` pointing to `multi-user.target`, which is the systemd equivalent of runlevel 3. Option D, `ln -sf /lib/systemd/system/multi-user.target /etc/systemd/system/default.target`, is correct because it manually performs the same action that `systemctl set-default` does, replacing the default.target symlink so the system boots into the multi-user target. Option A is wrong because `systemctl enable multi-user.target` only enables the unit to start at boot; it does not change the default boot target. Option B is wrong because `systemctl default multi-user` is not a valid command syntax. Option E is wrong because `runlevel3.target` is not a valid systemd target name; the correct target is `multi-user.target`.

Answer

systemctl enable multi-user.target

Answer

systemctl default multi-user

Answer

systemctl set-default runlevel3.target