CompTIA XK0-005 Online Practice Questions and Exam Preparation

CompTIA XK0-005 Online Questions & Answers

• Question 431:

  A systems administrator receives a report about performance issues in a Linux production system. Which of the following commands should the administrator use to help diagnose the performance issues?

  A. jobs
  B. renice
  C. top
  D. pkill
  C. top

  ---

  Explanation

• Question 432:

  A systems administrator is cloning a system partition /dev/sda1 to /dev/sdc1. Which of the following commands would allow the administrator to accomplish this task most efficiently?

  A. dd if=/dev/sda1 of=/dev/sdc1
  B. cat /dev/sda1 > /dev/sdc1
  C. cp -R /dev/sda1 /dev/sdc1
  D. rsync -av /dev/sda1 /dev/sdc1
  A. dd if=/dev/sda1 of=/dev/sdc1

  ---

  Explanation

  The dd command is the most efficient method to clone a partition, as it operates at the block level. The command dd if=/dev/sda1 of=/dev/sdc1 copies the entire content of /dev/sda1 (input file) to /dev/sdc1 (output file), making an exact clone of the partition. The other options are either not applicable or less efficient for partition cloning.

• Question 433:

  A Linux administrator logs into a system and identifies that an important backup has started. The backup process is consuming a considerable amount of CPU time but needs to continue. Which of the following should the administrator use to reduce the impact this process has on other services?

  A. renice -n 15 -p
  B. nice -n 15 -p
  C. renice -n -15 -p
  D. nice -n -15 -p
  A. renice -n 15 -p

  ---

  Explanation

  The renice command changes the scheduling priority of a running process. By using renice -n 15, the administrator lowers the priority of the backup process, making it less CPU- intensive and reducing its impact on other system services. A positive niceness value (e.g.,

  15) lowers the priority, allowing other processes to receive more CPU time.

• Question 434:

  A newly created container has been unable to start properly, and a Linux administrator is analyzing the cause of the failure. Which of the following will allow the administrator to determine the FIRST command that is executed inside the container right after it starts?

  A. docker export
  B. docker info
  C. docker start
  D. docker inspect
  D. docker inspect

  ---

  Explanation

  The command that will allow the administrator to determine the first command that is executed inside the container right after it starts is docker inspect . This command will display detailed information about the container,

  including its configuration, state, network settings, mounts, and logs. One of the configuration fields is "Entrypoint", which shows the command that is executed when the container is run. The entrypoint can be specified in the Dockerfile or overridden at runtime using the --entrypoint option.

  The other options are not correct commands for determining the first command that is executed inside the container. The docker export command will export the contents of the container's filesystem as a tar archive to STDOUT. This will not show the entrypoint of the container, but only its files. The docker info command is invalid because docker info does not take any arguments. It shows system-wide information about Docker, such as the number of containers, images, volumes, networks, and storage drivers. The docker start command will start a stopped container and attach its STDOUT and STDERR to the terminal. This will not show the entrypoint of the container, but only its output.

  References: docker inspect | Docker Docs; docker export | Docker Docs; docker info | Docker Docs; docker start | Docker Docs

• Question 435:

  A security team discovers that a web server has been running with elevated privileges and identifies it as a security violation. Which of the following items needs to be added to the webserver.service file to remediate the issue?

  A. In the [Service] section of the webserver.service file, add User=comptia.
  B. In the [Unit] section of the webserver.service file, add AllowIsolate=true.
  C. In the [Install] section of the webserver.service file, add WantedBy=single.target.
  D. Add After=network.target to the [Install] section of the webserver.service file.
  A. In the [Service] section of the webserver.service file, add User=comptia.

  ---

  Explanation

  Adding User=comptia in the [Service] section ensures that the web server runs as a non- root user, which enhances security by reducing the risk of elevated privileges being exploited. This follows the principle of least privilege, a best practice for system services.

• Question 436:

  A Linux administrator is troubleshooting SSH connection issues from one of the workstations.

  When users attempt to log in from the workstation to a server with the IP address 104.21.75.76, they receive the following message:

  

  The administrator reviews the information below:

  

  Which of the following is causing the connectivity issue?

  A. The workstation has the wrong IP settings.
  B. The sshd service is disabled.
  C. The server's firewall is preventing connections from being made.
  D. The server has an incorrect default gateway configuration.
  C. The server's firewall is preventing connections from being made.

  ---

  Explanation

  The server's firewall is preventing connections from being made, which is causing the connectivity issue. The output of iptables -L -n shows that the firewall is blocking all incoming traffic on port 22, which is the default port for SSH. The output of ssh -v [email protected] shows that the connection is refused by the server. To resolve the issue, the administrator needs to allow port 22 on the firewall. The other options are incorrect because they are not supported by the outputs. The workstation has the correct IP settings, as shown by the output of ip addr show. The sshd service is enabled and running, as shown by the output of systemct1 status sshd. The server has the correct default gateway configuration, as shown by the output of ip route show.

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 13: Managing Network Services, pages 406-407.

• Question 437:

  A Linux user is trying to execute commands with sudo but is receiving the following error:

  $ sudo visudo

  >>> /etc/sudoers: syntax error near line 28 <<<

  sudo: parse error in /etc/sudoers near line 28

  sudo: no valid sudoers sources found, quitting

  The following output is provided:

  # grep root /etc/shadow

  root :* LOCK *: 14600 ::::::

  Which of the following actions will resolve this issue?

  A. Log in directly using the root account and comment out line 28 from /etc/sudoers.
  B. Boot the system in single user mode and comment out line 28 from /etc/sudoers.
  C. Comment out line 28 from /etc/sudoers and try to use sudo again.
  D. Log in to the system using the other regular user, switch to root, and comment out line 28 from /etc/sudoers.
  B. Boot the system in single user mode and comment out line 28 from /etc/sudoers.

  ---

  Explanation

• Question 438:

  A systems administrator needs to compress log files using the .tar.bz2 format. Which of the following commands should the administrator use?

  A. tar -cvtf logs.car.bz2 /var/log/*
  B. tar -cvzf logs.tar.bz2 /var/log/*
  C. tar -cvjf logs.tar.bz2 /var/log/*
  D. tar -cvbf logs.tar.bz2 /var/log/*
  C. tar -cvjf logs.tar.bz2 /var/log/*

  ---

  Explanation

• Question 439:

  Users report issues when trying to securely connect to a web server. The systems administrator receives the following outputs:

  firewall-cmd --list-all

  # (Only ports for ssh, cockpit, dhcp-client are listed.)

  netstat -an | grep LISTEN

  tcp 0 0 0.0.0.0:443 ... LISTEN

  Which of the following actions will fix this issue?

  A. Restarting the firewall service
  B. Starting the web application
  C. Restarting the web application
  D. Opening firewall port 443
  D. Opening firewall port 443

  ---

  Explanation

• Question 440:

  A user sends a request to access a virtual server via SSH. Which of the following commands is used to open the SSH standard port?

  A. firewalld-cmd --permanent --add-port=22/tcp
  B. iptables-save | grep dport-22/tcp
  C. iptables -A INPUT -p tcp --dport sshd -j ACCEPT
  D. firewalld-cmd --remove-service=ssh --permanent
  A. firewalld-cmd --permanent --add-port=22/tcp

  ---

  Explanation