CompTIA XK0-005 Online Practice Questions and Exam Preparation

CompTIA XK0-005 Online Questions & Answers

• Question 461:

  Users report that they cannot access some files located in the /opt/finapp directory after a power outage caused an unexpected server restart. A Linux administrator examines the following filesystem details and system logs: # mount | grep finapp /dev/mapper/rhel-opt_finapp on /opt/finapp type xfs (rw,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota) # lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 931.5G 0 disk |-sda1 8:1 0 1G 0 part /boot

  |-sda2 8:2 0 930.5G 0 part |-rhel-root 253:0 0 30.5G 0 lvm / |-rhel-opt_finapp 253:1 0 900G 0 lvm /opt/finapp # grep opt_finapp /var/log/messages XFS (opt_finapp): Corruption detected in inode 3645, extent tree Which of the following commands should the administrator run in an attempt to fix the filesystem?

  A. fdisk /dev/mapper/rhel-opt_finapp
  B. xfs_repair /dev/mapper/rhel-opt_finapp
  C. lvcreate -L900G -n opt_finapp rhel
  D. fsck.ext4 /dev/mapper/rhel-opt_finapp
  B. xfs_repair /dev/mapper/rhel-opt_finapp

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  Explanation

• Question 462:

  A Linux system is getting an error indicating the root filesystem is full. Which of the following commands should be used by the systems administrator to resolve this issue? (Choose three.)

  A. df -h /
  B. fdisk -1 /dev/sdb
  C. growpart /dev/mapper/rootvg-rootlv
  D. pvcreate /dev/sdb
  E. lvresize -L +10G -r /dev/mapper/rootvg-rootlv
  F. lsblk /dev/sda
  G. parted -l /dev/mapper/rootvg-rootlv
  H. vgextend /dev/rootvg /dev/sdb
  A. df -h /
  C. growpart /dev/mapper/rootvg-rootlv
  E. lvresize -L +10G -r /dev/mapper/rootvg-rootlv

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  Explanation

  The administrator should use the following three commands to resolve the issue of the root filesystem being full:

  df -h /. This command will show the disk usage of the root filesystem in a human- readable format. The df command is a tool for reporting file system disk space usage. The -h option displays the sizes in powers of 1024 (e.g., 1K, 234M, 2G).

  The / specifies the root filesystem. The command df -h / will show the total size, used space, available space, and percentage of the root filesystem. This command will help the administrator identify the problem and plan the solution.

  growpart /dev/mapper/rootvg-rootlv. This command will grow the partition that contains the root filesystem to the maximum size available. The growpart command is a tool for resizing partitions on Linux systems. The /dev/mapper/rootvg-rootlv

  is the device name of the partition, which is a logical volume managed by the Logical Volume Manager (LVM). The command growpart /dev/mapper/rootvg-rootlv will extend the partition to fill the disk space and increase the size of the root

  filesystem. This command will help the administrator solve the problem and free up space.

  lvresize -L +10G -r /dev/mapper/rootvg-rootlv. This command will resize the logical volume that contains the root filesystem and add 10 GB of space. The lvresize command is a tool for resizing logical volumes on Linux systems. The -L option

  specifies the new size of the logical volume, in this case +10G, which means 10 GB more than the current size. The -r option resizes the underlying file system as well. The /dev/mapper/rootvg-rootlv is the device name of the logical volume,

  which is the same as the partition name. The command lvresize -L +10G -r /dev/mapper/rootvg-rootlv will increase the size of the logical volume and the root filesystem by 10 GB and free up space. This command will help the administrator

  solve the problem and free up space. The other options are incorrect because they either do not affect the root filesystem (fdisk - 1 /dev/sdb, pvcreate /dev/sdb, lsblk /dev/sda, or vgextend /dev/rootvg /dev/sdb) or do not use the correct syntax

  (fdisk -1 /dev/sdb instead of fdisk -l /dev/sdb or parted -l /dev/mapper/rootvg-rootlv instead of parted /dev/mapper/rootvg-rootlv print).

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 10:

  Managing Storage, pages 318-319, 331-332.

• Question 463:

  A Linux administrator is configuring network traffic forwarding. Despite having proper iptables rules, the traffic forwarding is not working. Which of the following commands will allow Linux to pass network traffic between different interfaces?

  A. nmcli allow-forwarding eth0
  B. echo 'net.ipv4.ip_forward=1' >> /etc/sysctl.conf; sysctl -p
  C. ip route forward allow --all-interfaces; systemctl restart network
  D. modprobe ip_forward
  B. echo 'net.ipv4.ip_forward=1' >> /etc/sysctl.conf; sysctl -p

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  Explanation

  To enable IP forwarding, the kernel parameter net.ipv4.ip_forward must be set to 1. This is done by appending net.ipv4.ip_forward=1 to /etc/sysctl.conf and applying the changes using sysctl -p. This command ensures that the system can forward packets between different network interfaces.

• Question 464:

  A developer is trying to install an application remotely that requires a graphical interface for installation. The developer requested assistance to set up the necessary environment variables along with X11 forwarding in SSH. Which of the following environment variables must be set in remote shell in order to launch the graphical interface?

  A. $RHOST
  B. SETENV
  C. $SHELL
  D. $DISPLAY
  D. $DISPLAY

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  Explanation

  The environment variable that must be set in remote shell in order to launch the graphical interface is $DISPLAY. This variable tells X11 applications where to display their windows on screen. It usually has the form hostname:displaynumber.screennumber, where hostname is the name of the computer running the X server, displaynumber is a unique identifier for an X display on that computer, and screennumber is an optional identifier for a screen within an X display. For example, localhost:0.0 means display number 0 on the local host. If the hostname is omitted, it defaults to the local host. The other options are not correct environment variables for launching the graphical interface. $RHOST is a variable that stores the name of the remote host, but it is not used by X11 applications. SETENV is a command that sets environment variables in some shells, but it is not an environment variable itself. $SHELL is a variable that stores the name of the current shell, but it is not related to X11 forwarding.

  References: How to enable or disable X11 forwarding in an SSH server; How to Configure X11 Forwarding Using SSH In Linux

• Question 465:

  A Linux systems administrator receives a report that a user is unable to start an application. The administrator reviews the following error: yaml

  Killed process 1141 (application) total-vm:5622584kB oom_score_adj:0 oom_reaper: reaped process 1141

  Which of the following describes the situation?

  A. The system does not have adequate CPU capacity to allocate to the application.
  B. The application is trying to connect to multiple remote systems without having an adequate number of connections available.
  C. The application is trying to open more files than the available disk can accommodate.
  D. The application is trying to allocate more memory than the available system and swap space can support.
  D. The application is trying to allocate more memory than the available system and swap space can support.

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  Explanation

• Question 466:

  A junior administrator is trying to set up a passwordless SSH connection to one of the servers. The administrator follows the instructions and puts the key in the authorized_key file at the server, but the administrator is still asked to provide a password during the connection.

  Given the following output:

  

  Which of the following commands would resolve the issue and allow an SSH connection to be established without a password?

  A. restorecon -rv .ssh/authorized_key
  B. mv .ssh/authorized_key .ssh/authorized_keys
  C. systemct1 restart sshd.service
  D. chmod 600 mv .ssh/authorized_key
  B. mv .ssh/authorized_key .ssh/authorized_keys

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  Explanation

  The command mv .ssh/authorized_key .ssh/authorized_keys will resolve the issue and allow an SSH connection to be established without a password. The issue is caused by the incorrect file name of the authorized key file on the server. The file should be named authorized_keys, not authorized_key. The mv command will rename the file and fix the issue. The other options are incorrect because they either do not affect the file name (restorecon or chmod) or do not restart the SSH service (systemct1).

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter

  13: Managing Network Services, page 410.

• Question 467:

  A Linux administrator needs to ensure that Java 7 and Java 8 are both locally available for developers to use when deploying containers. Currently only Java 8 is available. Which of the following commands should the administrator run to ensure both versions are available?

  A. docker image load java:7
  B. docker image pull java:7
  C. docker image import java:7
  D. docker image build java:7
  B. docker image pull java:7

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  Explanation

  The command that the administrator should run to ensure that both Java 7 and Java 8 are locally available for developers to use when deploying containers is docker image pull java:7. This command will use the docker image pull subcommand to download the java:7 image from Docker Hub, which is the default registry for Docker images. The java:7 image contains Java 7 installed on a Debian-based Linux system. The administrator can also specify a different registry by using the syntax registry/repository:tag. The other options are not correct commands for ensuring that both Java 7 and Java 8 are locally available for developers to use when deploying containers. The docker image load java:7 command will load an image from a tar archive or STDIN, not from a registry. The docker image import java:7 command will create a new filesystem image from the contents of a tarball, not from a registry. The docker image build java:7 command will build an image from a Dockerfile, not from a registry.

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 18: Automating Tasks; docker image pull | Docker Docs

• Question 468:

  A cloud engineer wants to delete all unused networks that are not referenced by any container. Which of the following commands will achieve this goal?

  A. docker network erase
  B. docker network clear
  C. docker network prune
  D. docker network rm
  C. docker network prune

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  Explanation

  The docker command is used to manage Docker containers, images, networks, volumes, and other resources on a Linux system. Docker is a platform that allows users to run applications in isolated environments called containers. Docker also provides networking features that allow users to create and manage networks for containers. To delete all unused networks that are not referenced by any container, the cloud engineer can use the docker network prune command. This command will remove all networks that have no containers connected to them. The statement C is correct. The statements A, B, and D are incorrect because they do not delete all unused networks. The docker network erase and docker network clear commands do not exist. The docker network rm command deletes a specific network by name or ID, but not all unused networks.

  References: [How to Manage Docker Networks]

• Question 469:

  A Linux administrator provisioned a new web server with custom administrative permissions for certain users. The administrator receives a report that user1 is unable to restart the Apache web service on this server. The administrator reviews the following output:

  [ root@server ] # id user1

  UID=1011 (user1) gid=1011 (USER1) groups=1011 (user1), 101 (www-data), 1120 (webadmin)

  [ root@server ] # cat /etc/sudoers.d/custom.conf

  user1 ALL=/usr/sbin/systemctl start httpd, /usr/sbin/systemctl stop httpd

  webadmin ALL=NOPASSWD: /etc/init.d.httpd restart, /sbin/service httpd restart, /usr/sbin/apache2ctl restart

  #%wheel ALL=(ALL) NOPASSWD: ALL

  Which of the following would most likely resolve the issue while maintaining a least privilege security model?

  A. User1 should be added to the wheel group to manage the service.
  B. User1 should have "NOPASSWD:" after the "ALL=" in the custom. conf.
  C. The wheel line in the custom. conf file should be uncommented.
  D. Webadmin should be listed as a group in the custom. conf file.
  D. Webadmin should be listed as a group in the custom. conf file.

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  Explanation

  The custom.conf file grants sudo privileges to user1 and webadmin for managing the Apache web service, but it uses different commands for each of them. User1 is allowed to use systemctl to start and stop the httpd service, while webadmin is allowed to use init.d, service, or apache2ctl to restart the httpd service. However, the user1 is unable to restart the service, only start and stop it. To fix this, user1 should be able to use the same commands as webadmin, which can be achieved by listing webadmin as a group in the custom.conf file, using the syntax %groupname. This way, user1 will inherit the sudo privileges of the webadmin group, and be able to restart the Apache web service without compromising the least privilege security model. References Sudo and Sudoers Configuration | Servers for Hackers, section "Groups" Chapter 12. Managing sudo access - Red Hat Customer Portal, section "12.1. Configuring sudo access for users and groups"

• Question 470:

  An average of one out of three users in a company cannot reach the company website. A Linux administrator determines that one of the three website servers is down. The administrator inspects the DNS configuration for the website and notices the following entry:

  www IN A 5.5.5.1 IN A 5.5.5.2 IN A 5.5.5.3

  Which of the following accurately explains the issue?

  A. The DNS configuration is missing corresponding AAAA records and PTR records, and this is causing clients to fail the hostname translation.
  B. The administrator has incorrectly configured the DNS server to be an iterative resolver instead of an authoritative resolver.
  C. One of the DNS records has not been signed with a DNSSEC-supported key, and this is causing some web browsers to reject the DNS response.
  D. DNS returns all three records in a different order each time, and the browser typically uses the first address in the DNS response.
  D. DNS returns all three records in a different order each time, and the browser typically uses the first address in the DNS response.

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  Explanation