CompTIA XK0-005 Online Practice Questions and Exam Preparation

CompTIA XK0-005 Online Questions & Answers

• Question 451:

  The journald entries have filled a Linux machine's /var volume. Which of the following is the best command for a systems administrator to use to free up the disk space occupied by these entries?

  A. journalctl --rotate journalctl --vacuum-time=1s
  B. systemctl stop systemd-journald systemctl start systemd-journald
  C. rm -rf /var/log/journal systemctl restart systemd-journald
  D. pkill -HUP systemd-journald systemctl restart systemd-journald
  B. systemctl stop systemd-journald systemctl start systemd-journald

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  Explanation

  systemctl stop systemd-journald systemctl start systemd-journald is the best approach among the given options. Stopping and starting the systemd-journald service can help in managing the disk space used by journal logs without manually deleting log files or using more aggressive cleanup methods. This method ensures that log management is handled gracefully by the system's own services.

• Question 452:

  A systems administrator installed a new software program on a Linux server. When the systems administrator tries to run the program, the following message appears on the screen.

  

  Which of the following commands will allow the systems administrator to check whether the system supports virtualization?

  A. dmidecode -s system-version
  B. lscpu
  C. sysctl -a
  D. cat /sys/device/system/cpu/possible
  B. lscpu

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  Explanation

  The command that will allow the systems administrator to check whether the system supports virtualization is lscpu. This command will display information about the CPU architecture, such as the number of CPUs, cores, sockets, threads, model name, frequency, cache size, and flags. One of the flags is vmx (for Intel processors) or svm (for AMD processors), which indicates that the CPU supports hardware virtualization. If the flag is present, it means that the system supports virtualization. If the flag is absent, it means that the system does not support virtualization or that it is disabled in the BIOS settings. The other options are not correct commands for checking whether the system supports virtualization. The dmidecode -s system-version command will display the version of the system, such as the product name or serial number, but not the CPU information. The sysctl -a command will display all the kernel parameters, but not the CPU flags. The cat /sys/devices/system/cpu/possible command will display the range of possible CPUs that can be online or offline, but not the CPU features.

  References: lscpu(1) - Linux manual page; How To Check If Virtualization is Enabled in Windows 10 / 11

• Question 453:

  A systems administrator needs to check if the service systemd-resolved.service is running without any errors. Which of the following commands will show this information?

  A. systemct1 status systemd-resolved.service
  B. systemct1 enable systemd-resolved.service
  C. systemct1 mask systemd-resolved.service
  D. systemct1 show systemd-resolved.service
  A. systemct1 status systemd-resolved.service

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  Explanation

  The command systemct1 status systemd-resolved.service will show the information about the service systemd-resolved.service. The systemct1 command is a tool for managing system services and units. The status option displays the current status of a unit, such as active, inactive, or failed. The output also shows the unit description, loaded configuration, process ID, memory usage, and recent log messages. This command will show if the service systemd-resolved.service is running without any errors. This is the correct command to use to accomplish the task. The other options are incorrect because they either perform different actions (enable, mask, or show) or do not show the status of the service (systemct1 show systemd-resolved.service only shows the properties of the service, not the status).

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 14: Managing Processes and Scheduling Tasks, page 427.

• Question 454:

  A systems administrator is investigating a service that is not starting up. Given the following information:

  

  Which of the following systemd commands should the administrator use in order to obtain more details about the failing service?

  A. systemct1 analyze network
  B. systemct1 info network
  C. sysctl -a network
  D. journalctl -xu network
  D. journalctl -xu network

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  Explanation

  The systemd is a system and service manager for Linux systems that provides a standard way to control and monitor system services. The systemd uses various commands and tools to manage and troubleshoot system services, such as systemct1, sysctl, and journalctl. The systemct1 command is used to start, stop, enable, disable, restart, reload, status, and list system services. The sysctl command is used to configure kernel parameters at runtime. The journalctl command is used to view and filter the logs of system services. To investigate a service that is not starting up, the administrator can use the journalctl command with the -xu option. The -x option enables verbose output that includes explanatory text and priority information. The -u option filters the output by a specific unit name, such as network.service. Therefore, the command journalctl -xu network will show detailed logs of the network service, which can help identify the cause of the failure. The statement D is correct. The statements A, B, and C are incorrect because they do not provide more details about the failing service. The systemct1 analyze network command does not exist. The systemct1 info network command shows basic information about the network unit, such as description, load state, active state, sub state, and main PID. The sysctl -a network command shows all kernel parameters related to network settings.

  References: [How to Use Systemd to Manage System Services]

• Question 455:

  A Linux administrator wants a permission bit on a shared folder that allows only the owner of the file within that directory or the root user to delete or rename the file. Which of the following commands will help achieve this goal?

  A. chmod u-w /directory/
  B. chmod a-r /directory/
  C. chmod o-t /directory/
  D. chmod +t /directory/
  D. chmod +t /directory/

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  Explanation

  The +t option sets the "sticky bit" on a directory, which restricts deletion or renaming of files in the directory to the file's owner or the root user. This is commonly used in shared directories like /tmp, where multiple users may have access, but only the file owner should be allowed to modify their own files. The command chmod +t /directory/ applies this permission.

• Question 456:

  A systems administrator is enabling LUKS on a USB storage device with an ext4 filesystem format. The administrator runs dmesg and notices the following output:

  

  Given this scenario, which of the following should the administrator perform to meet these requirements? (Select three).

  A. gpg /dev/sdcl
  B. pvcreate /dev/sdc
  C. mkfs . ext4 /dev/mapper/LUKSCJ001 - L ENCRYPTED
  D. umount / dev/ sdc
  E. fdisk /dev/sdc
  F. mkfs . vfat /dev/mapper/LUKS0001 -- L ENCRYPTED
  G. wipefs --a/dev/sdbl
  H. cryptsetup IuksFormat /dev/ sdcl
  C. mkfs . ext4 /dev/mapper/LUKSCJ001 - L ENCRYPTED
  D. umount / dev/ sdc
  H. cryptsetup IuksFormat /dev/ sdcl

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  Explanation

  To enable LUKS on a USB storage device with an ext4 filesystem format, the administrator needs to perform the following steps:

  Unmount the device if it is mounted using umount /dev/sdc (D) Create a partition table on the device using fdisk /dev/sdc (E) Format the partition with LUKS encryption using cryptsetup luksFormat /dev/sdc1 (H) Open the encrypted partition using cryptsetup luksOpen /dev/sdc1 LUKS0001 Create an ext4 filesystem on the encrypted partition using mkfs.ext4 /dev/mapper/LUKS0001 ? Mount the encrypted partition using mount /dev/mapper/LUKS0001 /mnt

  References:

  [CompTIA Linux+ Study Guide], Chapter 9: Securing Linux, Section: Encrypting Disks

  [How to Encrypt USB Drive on Ubuntu 18.04]

• Question 457:

  Which of the following is the best tool for dynamic tuning of kernel parameters?

  A. tuned
  B. tune2fs
  C. tuned-adm
  D. turbostat
  A. tuned

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  Explanation

  The tuned application is the best tool for dynamic tuning of kernel parameters, as it monitors the system and optimizes the performance under different workloads. It provides a number of predefined profiles for typical use cases, such as power saving, low latency, high throughput, virtual machine performance, and so on. It also allows users to create, modify, and delete profiles, and to switch between them on the fly. The tuned application uses the sysctl command and the configuration files in the /etc/sysctl.d/ directory to adjust the kernel parameters at runtime. References Chapter 2. Getting started with TuneD - Red Hat Customer Portal, paragraph 1 Kernel tuning with sysctl - Linux.com, paragraph 1

• Question 458:

  An administrator needs to install an Apache web server on an Ubuntu server. Which of the following commands should the administrator use?

  A. zypper install apache
  B. apt install apache2
  C. yum install httpd
  D. rpm -i apache.deb
  B. apt install apache2

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  Explanation

• Question 459:

  A systems technician is working on deploying several microservices to various RPM-based systems, some of which could run up to two hours. Which of the following commands will allow the technician to execute those services and continue deploying other microservices within the same terminal section?

  A. gedit and disown
  B. kill 9 %1
  C. fg %1
  D. bg %1 job name
  D. bg %1 job name

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  Explanation

  The command that will allow the technician to execute the services and continue deploying other microservices within the same terminal session is bg %1 job name. This command will send the job with ID 1 and name job name to the

  background, where it will run without occupying the terminal. The other options are incorrect because:

  gedit and disown will launch a graphical text editor in the background and detach it from the terminal, but it will not execute any service. kill 9 %1 will terminate the job with ID 1 using a SIGKILL signal, which cannot be ignored or handled by the

  process.

  fg %1 will bring the job with ID 1 to the foreground, where it will occupy the terminal until it finishes or is stopped.

  References: CompTIA Linux+ Study Guide, Fourth Edition, page 181-182.

• Question 460:

  A server is experiencing intermittent connection issues. Some connections to the Internet work as intended, but some fail as if there is no connectivity. The systems administrator inspects the server configuration:

  

  Which of the following is MOST likely the cause of the issue?

  A. An internal-only DNS server is configured.
  B. The IP netmask is wrong for ens3.
  C. Two default routes are configured.
  D. The ARP table contains incorrect entries.
  C. Two default routes are configured.

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  Explanation

  The most likely cause of the issue is that two default routes are configured on the server. The default route is the route that is used when no other route matches the destination of a packet. The default route is usually the gateway that connects the local network to the Internet. The server configuration shows that there are two default routes in the routing table, one with the gateway 192.168.1.1 and the other with the gateway 10.0.0.1. This can cause a conflict and confusion for the server when deciding which gateway to use for the outgoing packets. Some packets may be sent to the wrong gateway and fail to reach the Internet, while some packets may be sent to the correct gateway and work as intended. This can result in intermittent connection issues and inconsistent behavior. The administrator should remove one of the default routes and keep only the correct one for the network. This can be done by using the ip route del command or by editing the network configuration files. This will resolve the issue and restore the connectivity. The other options are incorrect because they are not supported by the outputs. The DNS server, the IP netmask, and the ARP table are not the causes of the issue.

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 12: Managing Network Connections, pages 381-382.