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

Question 1

A user is unable to log in via SSH. The administrator checks /var/log/secure and sees 'Authentication refused: bad ownership or modes' for the user's home directory. What is the most likely cause?

Accepted Answer

The user's home directory is owned by root. The error 'Authentication refused: bad ownership or modes' includes the path of the offending file. When the log message references the user's home directory, it means the home directory itself has incorrect ownership or permissions. SSH's StrictModes requires the home directory to be owned by the user and not writable by group or others. If the home directory is owned by root, sshd refuses authentication. The correct answer is D.

Answer

The sshd service is not running

Answer

The SELinux context is wrong

Answer

The .ssh/authorized_keys file has incorrect permissions

Question 2

A system has a new disk /dev/sdb that needs to be used as an LVM physical volume for an existing volume group 'vg_data'. Which sequence of commands is correct?

Accepted Answer

pvcreate /dev/sdb; vgextend vg_data /dev/sdb. The disk /dev/sdb must first be initialized as a physical volume using pvcreate, then added to the existing volume group vg_data using vgextend. This sequence properly extends the volume group with the new physical volume, as required by LVM.

Answer

vgcreate vg_data /dev/sdb; pvcreate /dev/sdb

Answer

lvextend vg_data /dev/sdb

Answer

pvcreate /dev/sdb; vgcreate vg_data /dev/sdb

Question 3

A cron job runs a script every hour and leaves many log files. The administrator wants to clean up log files older than 7 days in /var/log/myapp/. Which command should be added to a weekly cron job?

Accepted Answer

find /var/log/myapp -type f -mtime +7 -delete. `-mtime +7` matches files whose modification time is older than 7 days, and `-delete` safely removes them. This is the most efficient and standard approach for cleaning up old log files in a cron job, as it avoids spawning a separate process for each file.

Answer

find /var/log/myapp -type f -atime +7 -delete

Answer

find /var/log/myapp -type f -mtime +7 -exec rm {} \;

Answer

find /var/log/myapp -type f -ctime +7 -delete

Question 4

A system fails to boot and drops into an emergency shell. The administrator suspects a misconfigured /etc/fstab. Which command should be used to determine which filesystem is causing the boot issue?

Accepted Answer

journalctl -xb -p err. When a system fails to boot due to a misconfigured /etc/fstab, the emergency shell is entered. The `journalctl -xb -p err` command displays the systemd journal from the current boot (`-b`) with extended information (`-x`) and filters for error-level messages (`-p err`). This will show the exact mount failure and the offending filesystem entry, making it the correct diagnostic tool.

Answer

systemctl status local-fs.target

Answer

fsck -A

Answer

mount -a

Question 5

A user reports that they cannot create files in their home directory. The administrator checks permissions and sees drwxr-xr-x. What is the likely cause?

Accepted Answer

The user is not the owner of the directory. The permissions `drwxr-xr-x` mean the owner has read, write, and execute (rwx) access, while group and others have only read and execute (r-x). Since the user cannot create files (which requires write permission), the user must not be the owner of the directory. Only the owner (or root) can write to it, so the likely cause is that the user is not the owner.

Answer

The directory has the sticky bit set

Answer

The filesystem is read-only

Answer

The user is not in the group

Question 6

An administrator wants to temporarily disable the firewalld service for troubleshooting. Which command will stop the service and prevent it from starting on subsequent boots?

Accepted Answer

systemctl disable --now firewalld. `systemctl disable --now firewalld` both stops the service immediately (via `--now`) and disables it from starting automatically on subsequent boots. This meets the requirement of temporarily disabling the service for troubleshooting while preventing it from starting after reboot.

Answer

systemctl stop --now firewalld

Answer

systemctl mask firewalld

Answer

systemctl stop firewalld

Answer

systemctl disable firewalld

Question 7

An administrator needs to configure a static IP address on an interface that will persist across reboots using NetworkManager. Which TWO commands or files can be used to achieve this?

Accepted Answer

nmcli con mod eth0 ipv4.addresses 192.168.1.10/24. The `nmcli con mod` command modifies the NetworkManager connection profile for the interface, setting a static IPv4 address that is stored persistently in the connection configuration. Option D is correct because editing the `/etc/sysconfig/network-scripts/ifcfg-eth0` file directly defines the static IP address in the ifcfg format, which NetworkManager reads on boot to apply persistent settings.

Answer

systemctl restart network

Answer

nmcli con up eth0

Answer

ip addr add 192.168.1.10/24 dev eth0

Question 8

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 9

Refer to the exhibit. A user 'alice' is unable to write to /data directory. What is the most likely reason?

Accepted Answer

The directory permissions restrict access. The exhibit (not shown here) likely displays directory permissions such as 'drwxr-xr-x' or 'drwx------' that do not grant write access to the user 'alice'. In Linux, the write permission (w) on a directory controls whether a user can create, delete, or rename files within it. Since 'alice' lacks write permission on /data, she cannot write to it, regardless of ownership or filesystem space.

Answer

The filesystem is nearly full

Answer

The directory is owned by root and alice is not root

Answer

The directory has ACLs preventing access

Question 10

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 11

A technician needs to configure a network interface to use a static IP address permanently. Which command should be used in RHEL 9?

Accepted Answer

nmcli. `nmcli` is the primary command-line tool for managing NetworkManager in RHEL 9, and it allows you to configure a static IP address persistently. Using `nmcli con mod` followed by the connection name and IP settings ensures the configuration survives reboots, as NetworkManager stores the settings in its own configuration files.

Answer

ip

Answer

vi /etc/sysconfig/network-scripts/ifcfg-eth0

Answer

ifconfig

Question 12

A cron job fails to run. Which command should the administrator use to verify the cron daemon is active?

Accepted Answer

systemctl status crond. On RHEL-based systems (including Red Hat Enterprise Linux, CentOS, and Fedora), the cron daemon is named `crond`, not `cron`. The `systemctl status crond` command checks whether the `crond` service is active, enabled, and running. This is the correct method for verifying the cron daemon's status on systems using systemd.

Answer

systemctl status cron

Answer

systemctl list-units --type=service

Answer

service crond status

Question 13

A user reports that they cannot start a service. Which command would an administrator use to view the service's journal logs since last boot?

Accepted Answer

journalctl -u service -b. `journalctl -u service -b` combines the `-u` flag to filter logs for a specific systemd unit (the service) with the `-b` flag to show only logs from the current boot. This is the precise command an administrator would use to view a service's journal logs since the last system start, directly addressing the user's inability to start the service.

Answer

journalctl -b

Answer

journalctl service

Answer

dmesg | grep service

Question 14

A system has a disk that may be failing. Which tool can be used to check the health of a SATA disk using SMART monitoring?

Accepted Answer

smartctl. smartctl is the correct tool because it directly interfaces with the Self-Monitoring, Analysis, and Reporting Technology (SMART) built into modern SATA and ATA drives. It can query the drive's internal health metrics, such as reallocated sector counts and temperature, to predict potential failure. The other options do not access SMART data.

Answer

fsck

Answer

dd

Answer

badblocks

Question 15

An administrator needs to configure system tuning profiles for a database server. Which command is used to set the 'throughput-performance' profile?

Accepted Answer

tuned-adm profile throughput-performance. The `tuned-adm profile throughput-performance` command is correct because Tuned is the system tuning service on Red Hat Enterprise Linux, and `tuned-adm` is the command-line tool used to activate predefined tuning profiles. The 'throughput-performance' profile optimizes the system for maximum network and disk throughput by disabling power-saving features and tuning kernel parameters.

Answer

powertop --set-profile=throughput-performance

Answer

sysctl -w kernel.throughput=1

Answer

systemctl set-profile throughput-performance