CompTIA XK0-005 Online Practice Questions and Exam Preparation

CompTIA XK0-005 Online Questions & Answers

• Question 191:

  Users connecting to a MySQL database on a Linux system report frequent errors. An administrator reviews the following partial output of the /proc/meminfo and free commands: Which of the following should the administrator do to ensure that the MySQL service will continue to run even if the system runs out of swap space? (Select two.)

  

  A. Issue the sysctl -w vm.overcommit_ratio=100 command.
  B. Issue the sysctl -w vm.overcommit_memory=2 command.
  C. Issue the dd if=/dev/zero of=/swapfile bs=1024 count=65536 command.
  D. Issue the mkswap /dev/sda2; swapon -v /dev/sda2 command.
  E. Reload the /etc/fstab file by issuing the mount -a command.
  F. Use disk quotas on the swap space to prevent MySQL from overutilizing the swap partition.
  C. Issue the dd if=/dev/zero of=/swapfile bs=1024 count=65536 command.
  D. Issue the mkswap /dev/sda2; swapon -v /dev/sda2 command.

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  Explanation

• Question 192:

  A systems administrator wants to check for running containers. Which of the following commands can be used to show this information?

  A. docker pull
  B. docker stats
  C. docker ps
  D. docker list
  C. docker ps

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  Explanation

  The command that can be used to check for running containers is docker ps. The docker ps command can list all the containers that are currently running on the system. To show all the containers, including those that are stopped, the administrator can use docker ps -a ?

  References:

  [CompTIA Linux+ Study Guide], Chapter 11: Working with Containers, Section:

  Managing Containers with Docker

  [Docker PS Command with Examples]

• Question 193:

  A systems administrator received a request to change a user's credentials. Which of the following commands will grant the request?

  A. sudo passwd
  B. sudo userde 1
  C. sudo chage
  D. sudo usermod
  A. sudo passwd

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  Explanation

  This command will allow the systems administrator to change the password of another user account in the system. The sudo prefix will grant the administrator the necessary privileges to perform this action, and the passwd command will prompt for the new password for the specified user. For example, if the administrator wants to change the password of a user named tom, the command will look like this:

  sudo passwd tom

  The other options are incorrect because:

  B. sudo userdel

  This command will delete a user account from the system, not change its credentials. The userdel command removes the user's entry from the /etc/passwd and /etc/shadow files, as well as deletes the user's home directory and mail spool.

  This is not what the request asked for.

  C. sudo chage

  This command will change the password expiration and aging information for a user account, not its credentials. The chage command can be used to set or modify various parameters related to password aging, such as the minimum and maximum number of days between password changes, the number of days before password expiration to issue a warning, and so on. This is not what the request asked for.

  D. sudo usermod

  This command will modify various attributes of a user account, such as its login name, home directory, default shell, primary group, and so on. However, it cannot change the user's password directly. To do that, the usermod command requires the -p option followed by an encrypted password string, which is not easy to generate manually. Therefore, this is not a practical way to change a user's credentials.

  References:

  How to Change Account Passwords on Linux

  How to Change a Password in Linux for Root and Other Users CompTIA Linux+ Certification Exam Objectives

• Question 194:

  A Linux administrator would like to use systemd to schedule a job to run every two hours. The administrator creates timer and service definitions and restarts the server to load these new configurations. After the restart, the administrator checks the log file and notices that the job is only running daily. Which of the following is MOST likely causing the issue?

  A. The checkdiskspace.service is not running.
  B. The checkdiskspace.service needs to be enabled.
  C. The OnCalendar schedule is incorrect in the timer definition.
  D. The system-daemon services need to be reloaded.
  C. The OnCalendar schedule is incorrect in the timer definition.

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  Explanation

  The OnCalendar schedule is incorrect in the timer definition, which is causing the issue. The OnCalendar schedule defines when the timer should trigger the service. The format of the schedule is OnCalendar=--

  ::. If any of the fields are omitted, they are assumed to be *, which means any value. Therefore, the schedule OnCalendar=*-*-* 00:00:00 means every day at midnight, which is why the job is running daily. To make the job run every two hours, the schedule should be OnCalendar=*-*-* *:00:00/2, which means every hour divisible by 2 at the start of the minute. The other options are incorrect because they are not related to the schedule. The checkdiskspace.service is running, as shown by the output of systemct1 status checkdiskspace.service. The checkdiskspace.service is enabled, as shown by the output of systemct1 is-enabled checkdiskspace.service. The system-daemon services do not need to be reloaded, as the timer and service definitions are already loaded by the restart.

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 14: Managing Processes and Scheduling Tasks, page 437.

• Question 195:

  Which of the following specifications is used to perform disk encryption in a Linux system?

  A. LUKS
  B. TLS
  C. SSL
  D. NFS
  A. LUKS

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  Explanation

  LUKS stands for Linux Unified Key Setup, which is a specification for disk encryption on Linux systems. LUKS allows users to encrypt partitions or entire disks using a passphrase or a key file. LUKS also supports multiple keys and key slots, which can be used to unlock the encrypted data. LUKS is compatible with various tools and utilities, such as cryptsetup, dm-crypt, and LVM.

  References: [How to Encrypt Partitions with LUKS on Linux]

• Question 196:

  A systems administrator needs to reconfigure a Linux server to allow persistent IPv4 packet forwarding. Which of the following commands is the correct way to accomplish this task?

  A. echo 1 > /proc/sys/net/ipv4/ipv_forward
  B. sysctl -w net.ipv4.ip_forward=1
  C. firewall-cmd --enable ipv4_forwarding
  D. systemct1 start ipv4_forwarding
  B. sysctl -w net.ipv4.ip_forward=1

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  Explanation

  The command sysctl -w net.ipv4.ip_forward=1 enables IPv4 packet forwarding temporarily by setting the kernel parameter net.ipv4.ip_forward to 1. To make this change persistent, the administrator needs to edit the file /etc/sysctl.conf and add the line net.ipv4.ip_forward = 1. The other options are incorrect because they either use the wrong file (/proc/sys/net/ipv4/ipv_forward), the wrong command (firewall- cmd or systemct1), or the wrong option (--enable or start).

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 12: Managing Network Connections, page 378.

• Question 197:

  Which of the following technologies provides load balancing, encryption, and observability in containerized environments?

  A. Virtual private network
  B. Sidecar pod
  C. Overlay network
  D. Service mesh
  D. Service mesh

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  Explanation

  "A service mesh controls the delivery of service requests in an application. Common features provided by a service mesh include service discovery, load balancing, encryption and failure recovery." The technology that provides load balancing, encryption, and observability in containerized environments is service mesh. A service mesh is a dedicated infrastructure layer that manages the communication and security between microservices in a distributed system. A service mesh consists of two components: a data plane and a control plane. The data plane is composed of proxies that are deployed alongside the microservices as sidecar pods. The proxies handle the network traffic between the microservices and provide features such as load balancing, encryption, authentication, authorization, routing, and observability. The control plane is responsible for configuring and managing the data plane and providing a unified interface for the administrators and developers. A service mesh can help improve the performance, reliability, and security of containerized applications and simplify the development and deployment process. A service mesh is the technology that provides load balancing, encryption, and observability in containerized environments. This is the correct answer to the question. The other options are incorrect because they either do not provide all the features of a service mesh (virtual private network or overlay network) or are not a technology but a component of a service mesh (sidecar pod).

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 19: Managing Cloud and Virtualization Technologies, page 574. https://www.techtarget.com/searchitoperations/definition/service-mesh

• Question 198:

  A User on a Linux workstation needs to remotely start an application on a Linux server and then forward the graphical display of that application back to the Linux workstation. Which of the following would enable the user to perform this action?

  A. ssh -X user@server application
  B. ssh -y user@server application
  C. ssh user@server application
  D. ssh -D user@server application
  A. ssh -X user@server application

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  Explanation

  The ssh -X option enables X11 forwarding, which allows the user to run graphical applications on the remote server and display them on the local workstation. The user needs to specify the username, the server address, and the application name after the ssh -X command. The remote server also needs to have X11Forwarding enabled and xauth installed for this to work.

  References:

  The web search result 8 explains how to run a GUI application through SSH by configuring both the SSH client and server.

  The web search result 6 provides a detailed answer on how to forward X over SSH to run graphics applications remotely, with examples and troubleshooting tips. The CompTIA Linux+ Certification Exam Objectives mention that the candidate should be able to "use SSH for remote access and management" as part of the System Operation and Maintenance domain1.

• Question 199:

  A systems administrator engineer wants to configure a Linux server's time zone to America/Chicago. The engineer verifies that the server's time zone is configured for Asia/Tokyo:

  

  Which of the following commands should the engineer execute to make this change?

  A. date configure -set-timezone America/Chicago
  B. set-timezone -config America/Chicago
  C. time date set America/Chicago
  D. timedatect1 set-timezone America/Chicago
  D. timedatect1 set-timezone America/Chicago

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  Explanation

• Question 200:

  A systems engineer has deployed a new application server, but the server cannot communicate with the backend database hostname. The engineer confirms that the application server can ping the database server's IP address. Which of the following is the most likely cause of the issue?

  A. Incorrect DNS servers
  B. Unreachable default gateway
  C. Missing route configuration
  D. Misconfigured subnet mask
  A. Incorrect DNS servers

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  Explanation

  This is because the application server can ping the database server's IP address, but not its hostname, which suggests that the DNS resolution is not working properly. DNS servers are responsible for translating hostnames into IP addresses, and vice versa. If the application server has incorrect or unreachable DNS servers configured, it will not be able to resolve the hostname of the database server and communicate with it. To troubleshoot this issue, the systems engineer should check the DNS configuration on the application server, which is usually stored in the /etc/resolv.conf file. This file should contain valid nameserver entries that point to the DNS servers that can resolve the database server's hostname. For example, a typical /etc/resolv.conf file may look like this: nameserver 8.8.8.8 nameserver 8.8.4.4 These are the IP addresses of Google's public DNS servers, which can be used as a fallback option if the default DNS servers are not working. Alternatively, the systems engineer can use the nslookup or dig commands to test the DNS resolution of the database server's hostname from the application server. These commands will query a specified DNS server and return the IP address of the hostname, or an error message if the resolution fails. For example, to query Google's public DNS server for the IP address of comptia.org, the command would be: nslookup comptia.org 8.8.8.8 or dig comptia.org @8.8.8.8