CompTIA CompTIA Certifications XK0-005 Questions & Answers

• Question 261:

  A systems administrator created a web server for the company and is required to add a tag for the API so end users can connect. Which of the following would the administrator do to complete this requirement?

  A. hostnamectl status --no-ask-password

  B. hostnamectl set-hostname "$(perl -le "print" "A" x 86)"

  C. hostnamectl set-hostname Comptia-WebNode -H [email protected]

  D. hostnamectl set-hostname Comptia-WebNode --transient

  Correct Answer: C

  Explanation: The command hostnamectl set-hostname Comptia-WebNode -H [email protected] sets the hostname of the web server to Comptia-WebNode and connects to the server using the SSH protocol and the root user. This is the correct way to complete the requirement. The other options are incorrect because they either display the current hostname status (hostnamectl status), set an invalid hostname (hostnamectl set- hostname "$(perl -le "print" "A" x 86)"), or set a transient hostname that is not persistent (hostnamectl set-hostname Comptia-WebNode --transient). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 9: Managing System Components, page 291.

• Question 262:

  A cloud engineer needs to launch a container named web-01 in background mode. Which of the following commands will accomplish this task''

  A. docker builder -f --name web-01 httpd

  B. docker load --name web-01 httpd

  C. docker ps -a --name web-01 httpd

  D. docker run -d --name web-01 httpd

  Correct Answer: D

  Explanation: The docker run -d --name web-01 httpd command will launch a container named web-01 in background mode. This command will create and start a new container from the httpd image, assign it the name web-01, and run it in

  detached mode (-d), which means the container will run in the background without attaching to the current terminal. The docker builder -f --name web-01 httpd command is invalid, as builder is not a valid docker command, and -f and --name

  are not valid options for docker build. The docker load --name web-01 httpd command is invalid, as load does not accept a --name option, and httpd is not a valid file name for load. The docker ps -a --name web-01 httpd command is invalid,

  as ps does not accept a --name option, and httpd is not a valid filter for ps. References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 16:

  Virtualization and Cloud Technologies, page 499.

• Question 263:

  A Linux administrator is reviewing changes to a configuration file that includes the following section:

  

  The Linux administrator is trying to select the appropriate syntax formatter to correct any issues with the configuration file. Which of the following should the syntax formatter support to meet this goal?

  A. Markdown

  B. XML

  C. YAML

  D. JSON

  Correct Answer: C

  Explanation: The configuration file shown in the image is written in YAML format, so the syntax formatter should support YAML to correct any issues with the file. YAML stands for YAML Ain't Markup Language, and it is a human-readable data serialization language that uses indentation and colons to define key-value pairs. YAML supports various data types, such as scalars, sequences, mappings, anchors, aliases, and tags. The configuration file follows the rules and syntax of YAML, while the other options do not. Markdown is a lightweight markup language that uses plain text formatting to create rich text documents. XML is a markup language that uses tags to enclose elements and attributes. JSON is a data interchange format that uses curly braces to enclose objects and square brackets to enclose arrays. References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 21: Automating Tasks with Ansible, page 591.

• Question 264:

  Which of the following commands will display the operating system?

  A. uname -n

  B. uname -s

  C. uname -o

  D. uname -m

  Correct Answer: C

  Explanation: The command that will display the operating system is uname -o. This command uses the uname tool, which is used to print system information such as the kernel name, version, release, machine, and processor. The -o option stands for operating system, and prints the name of the operating system implementation (usually GNU/Linux). The other options are not correct commands for displaying the operating system. The uname -n command will display the network node hostname of the system. The uname -s command will display the kernel name of the system. The uname -m command will display the machine hardware name of the system. References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 1: Exploring Linux Command-Line Tools; uname(1) - Linux manual page

• Question 265:

  A systems administrator pressed Ctrl+Z after starting a program using the command line, and the shell prompt was presented. In order to go back to the program, which of the following commands can the administrator use?

  A. fg

  B. su

  C. bg

  D. ed

  Correct Answer: A

  Explanation: Ctrl+Z suspended the process, and "fg" will bring it back into the foreground of the shell

  A Comprehensive and Detailed Explanation: To go back to a program that was suspended by pressing Ctrl+Z in the command line, the command that can be used is fg. The fg command stands for foreground, and it resumes the job that is next in the queue and brings it to the foreground. Alternatively, if there are more than one suspended jobs, fg can be followed by a job number to resume a specific job. The other commands are incorrect because they either do not resume a suspended job, or they have different functions such as switching user (su), pushing a job to the background (bg), or editing a file (ed). References: CompTIA Linux+ Study Guide, Fourth Edition, page 181-182.

• Question 266:

  The group named support is unable to make changes to the config file. An administrator is reviewing the permissions and sees the following:

  S Is -1 config

  -rw-rw----. 1 root app 4682 02-15 11:25 config

  Which of the following should the administrator execute in order to give the support group access to modify the file while preserving the current ownership?

  A. chown :support config

  B. setfacl -m g:support:rw- config

  C. chmod 664 config

  D. chmod g+s config

  Correct Answer: C

  To give the support group access to modify the config file while preserving the current ownership, the administrator can execute the command chmod 664 config ? This will change the permissions of the config file to read and write for the owner and group, and read only for others. The owner and group of the file will remain as root and app respectively. The other commands will not achieve this task, but either change the group ownership, set an access control list, or set a setgid bit. References: [CompTIA Linux+ Study Guide], Chapter 3: Working with Files, Section: Changing File Permissions [How to Use chmod Command in Linux]

• Question 267:

  A systems administrator receives reports that several virtual machines in a host are responding slower than expected. Upon further investigation, the administrator obtains the following output from one of the affected systems:

  

  Which of the following best explains the reported issue?

  A. The physical host is running out of CPU resources, leading to insufficient CPU time being allocated to virtual machines.

  B. The physical host has enough CPU cores, leading to users running more processes to compensate for the slower response times.

  C. The virtual machine has enough CPU cycles, leading to the system use percentage being higher than expected.

  D. The virtual machine is running out of CPU resources, leading to users experiencing longer response times.

  Correct Answer: D

  Explanation: Based on the output from one of the affected systems, the best explanation for the reported issue is that the virtual machine is running out of CPU resources, leading to users experiencing longer response times (D). The output shows that the system use percentage is very high (57.85%), indicating that the virtual machine is using most of its CPU cycles for system processes. This leaves little CPU time for user processes, which results in slower performance. The other explanations are not supported by the output or are contradictory. References: [CompTIA Linux+ Study Guide], Chapter 8: Optimizing Linux Performance, Section: Monitoring CPU Usage [How to Interpret CPU Usage Statistics]

• Question 268:

  A Linux systems administrator needs to persistently enable IPv4 forwarding in one of the Linux systems. Which of the following commands can be used together to accomplish this task? (Choose two.)

  A. sysctl net.ipv4.ip_forward

  B. sysctl -w net.ipv4.ip_forward=1

  C. echo "net.ipv4.ip_forward=1" >> /etc/sysctl.conf

  D. echo 1 > /proc/sys/net/ipv4/ip_forward

  E. sysctl -p

  F. echo "net.ipv6.conf.all.forwarding=l" >> /etc/sysctl.conf

  Correct Answer: BE

  Explanation: The commands that can be used together to persistently enable IPv4 forwarding in one of the Linux systems are sysctl -w net.ipv4.ip_forward=1 and sysctl -p. The first command will use sysctl to write a new value (1) to the

  net.ipv4.ip_forward kernel parameter, which controls whether IP forwarding is enabled or disabled for IPv4. This will enable IP forwarding immediately without rebooting. However, this change is temporary and will be lost after a reboot or a

  system reload. To make it permanent, we need to use the second command sysctl -p, which will load kernel parameters from /etc/sysctl.conf file. This file contains key-value pairs of kernel parameters and their values. To make sure that

  net.ipv4.ip_forward is set to 1 in this file, we can either edit it manually or append it using echo "net.ipv4.ip_forward=1" >> /etc/sysctl.conf.

  The other options are not correct commands for persistently enabling IPv4 forwarding. The sysctl net.ipv4.ip_forward command will only display the current value of net.ipv4.ip_forward parameter, but not change it. The echo 1 > /proc/sys/net/

  ipv4/ip_forward command will write 1 to /proc/sys/net/ipv4/ip_forward file, which is another way to change net.ipv4.ip_forward parameter. However, this change is also temporary and will not survive a reboot or a system reload. The echo

  "net.ipv6.conf.all.forwarding=l" >> /etc/sysctl.conf command will append a line to /etc/sysctl.conf file that sets net.ipv6.conf.all.forwarding parameter to 1. However, this parameter controls whether IP forwarding is enabled or disabled for IPv6,

  not IPv4. References: sysctl(8) - Linux manual page; Configure Linux as a Router (IP Forwarding)

• Question 269:

  A systems administrator is investigating an issue in which one of the servers is not booting up properly. The journalctl entries show the following:

  

  Which of the following will allow the administrator to boot the Linux system to normal mode quickly?

  A. Comment out the /opt/app filesystem in /etc/fstab and reboot.

  B. Reformat the /opt/app filesystem and reboot.

  C. Perform filesystem checks on local filesystems and reboot.

  D. Trigger a filesystem relabel and reboot.

  Correct Answer: A

  Explanation: The fastest way to boot the Linux system to normal mode is to comment out the /opt/app filesystem in /etc/fstab and reboot. This will prevent the system from trying to mount the /opt/app filesystem at boot time, which causes an error because the filesystem does not exist or is corrupted. Commenting out a line in /etc/fstab can be done by adding a # symbol at the beginning of the line. Rebooting the system will apply the changes and allow the system to boot normally. Reformatting the /opt/app filesystem will not help to boot the system, as it will erase any data on the filesystem and require manual intervention to create a new filesystem. Performing filesystem checks on local filesystems will not help to boot the system, as it will not fix the missing or corrupted /opt/app filesystem. Triggering a filesystem relabel will not help to boot the system, as it will only change the security context of files and directories according to SELinux policy. References: CompTIA Linux+ (XK0- 005) Certification Study Guide, Chapter 14: Managing Disk Storage, page 456.

• Question 270:

  A systems administrator has been unable to terminate a process. Which of the following should the administrator use to forcibly stop the process?

  A. kill -1

  B. kill -3

  C. kill -15

  D. kill -HUP

  E. kill -TERM

  Correct Answer: E

  Explanation: The administrator should use the command kill -TERM to forcibly stop the process. The kill command is a tool for sending signals to processes on Linux systems. Signals are messages that inform the processes about certain events and actions. The processes can react to the signals by performing predefined or user-defined actions, such as terminating, suspending, resuming, or ignoring. The -TERM option specifies the signal name or number that the kill command should send. The TERM signal, which stands for terminate, is the default signal that the kill command sends if no option is specified. The TERM signal requests the process to terminate gracefully, by closing any open files, releasing any resources, and performing any cleanup tasks. However, if the process does not respond to the TERM signal, the kill command can send a stronger signal, such as the KILL signal, which forces the process to terminate immediately, without any cleanup. The administrator should use the command kill -TERM to forcibly stop the process. This is the correct answer to the question. The other options are incorrect because they either do not terminate the process (kill -1 or kill 3) or do not terminate the process forcibly (kill -15 or kill -HUP). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 14: Managing Processes, page 431.