CompTIA XK0-005 CompTIA Linux+ Certification Exam Practice Test

Answer : D

Answer : D

The commandssh-copy-id user@serverwill allow the user to upload the public key to a remote server and enable passwordless login. Thessh-copy-idcommand is a tool for copying the public key to a remote server and appending it to theauthorized_keysfile, which is used for public key authentication. The command will also set the appropriate permissions on the remote server to ensure the security of the key. The commandssh-copy-id user@serverwill copy the public key of the user to the server and allow the user to log in without a password. This is the correct command to use for this task. The other options are incorrect because they either do not copy the public key (scp,rsync, orssh-add) or do not use the correct syntax (scp ~/.ssh/id_rsa user@server:~/instead ofscp ~/.ssh/id_rsa.pub user@server:~/orrsync ~ /.ssh/ user@server:~/instead ofrsync ~/.ssh/id_rsa.pub user@server:~/).Reference:CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 13: Managing Network Services, page 410.

Answer : A

Based on the output of the image sent by the user, the system is under CPU pressure and will require additional vCPUs. The output shows that there are four processes running upload.sh scripts that are consuming a high percentage of CPU time (99.7%, 99.6%, 99.5%, and 99.4%). The output also shows that the system has only 4 vCPUs, which means that each process is using almost one entire vCPU. This indicates that the system is struggling to handle the CPU load and may experience performance issues or slowdowns. Adding more vCPUs to the system would help to alleviate the CPU pressure and improve the system performance. The system has not been running for over a year, as the uptime command shows that it has been up for only 1 day, 2 hours, and 13 minutes. The number of users logged in to the system is not relevant to the performance issue, as they are not consuming significant CPU resources. The system does not require more memory, as the free command shows that it has plenty of available memory (49 GB total, 48 GB free).Reference:CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 15: Managing Memory and Process Execution, pages 468-469.

Answer : B

Answer : A, C, E

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. Thedfcommand is a tool for reporting file system disk space usage. The-hoption displays the sizes in powers of 1024 (e.g., 1K, 234M, 2G). The/specifies the root filesystem. The commanddf -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. Thegrowpartcommand is a tool for resizing partitions on Linux systems. The/dev/mapper/rootvg-rootlvis the device name of the partition, which is a logical volume managed by the Logical Volume Manager (LVM). The commandgrowpart /dev/mapper/rootvg-rootlvwill 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. Thelvresizecommand is a tool for resizing logical volumes on Linux systems. The-Loption specifies the new size of the logical volume, in this case +10G, which means 10 GB more than the current size. The-roption resizes the underlying file system as well. The/dev/mapper/rootvg-rootlvis the device name of the logical volume, which is the same as the partition name. The commandlvresize --L +10G -r /dev/mapper/rootvg-rootlvwill 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, orvgextend /dev/rootvg /dev/sdb) or do not use the correct syntax (fdisk -1 /dev/sdbinstead offdisk -l /dev/sdborparted -l /dev/mapper/rootvg-rootlvinstead ofparted /dev/mapper/rootvg-rootlv print).Reference:CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 10: Managing Storage, pages 318-319, 331-332.

Answer : B

The commandsysctl -w net.ipv4.ip_forward=1enables 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 linenet.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-cmdorsystemct1), or the wrong option (--enableorstart).Reference:CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 12: Managing Network Connections, page 378.

Answer : B

The command that would address the memory-related issue is kill -9 8321. This command will send a SIGKILL signal to the process with the PID 8321, which is the mysqld process that is using 99.7% of the available memory according to the top output. The SIGKILL signal will terminate the process immediately and free up the memory it was using. However, this command should be used with caution as it may cause data loss or corruption if the process was performing some critical operations.

The other options are not correct commands for addressing the memory-related issue. The top -p 8321 command will only display information about the process with the PID 8321, but will not kill it or reduce its memory usage. The renice -10 8321 command will change the priority (niceness) of the process with the PID 8321 to -10, which means it will have a higher scheduling priority, but this will not affect its memory consumption. The free 8321 command is invalid because free does not take a PID as an argument; free only displays information about the total, used, and free memory in the system.Reference:How to troubleshoot Linux server memory issues;kill(1) - Linux manual page