XK0-005 System Management Practice Test 9 — 15 Questions

Question 1

A server has a volume group 'vg_data' with a single logical volume 'lv_data' of 100GB mounted at /data. The filesystem on lv_data is XFS. The administrator needs to extend it to 150GB. A new 60GB disk /dev/sdc has been added and partitioned as LVM. The administrator runs `pvcreate /dev/sdc1`, then `vgextend vg_data /dev/sdc1`, then `lvextend -L +50G /dev/vg_data/lv_data`. The administrator runs `df -h /data` and sees that the filesystem still shows 100GB. Which command should be run next?

Accepted Answer

xfs_growfs /data. For XFS filesystems, after extending the logical volume, the filesystem must be grown using xfs_growfs with the mount point as argument. resize2fs is for ext2/3/4. Option C checks the filesystem, but it's not needed. Option D would shrink, which is incorrect.

Answer

lvreduce -L -50G /dev/vg_data/lv_data

Answer

fsck /dev/vg_data/lv_data

Answer

resize2fs /dev/vg_data/lv_data

Question 2

A custom application service 'myapp.service' fails to start on a RHEL 8 system with the error: "Failed at step EXEC spawning /usr/local/bin/myapp: Permission denied". The service runs as user 'myapp'. The binary /usr/local/bin/myapp has permissions 755 and is owned by root:root. The user myapp is not in the sudoers. The administrator checks SELinux and finds the binary has the context 'unconfined_u:object_r:usr_t:s0'. The service unit file does not specify any SELinux context. What is the most likely cause of the failure?

Accepted Answer

The SELinux context of the binary is incorrect; it should be bin_t.. The error occurs because SELinux is enforcing and the binary has the type 'usr_t', which is not allowed to be executed by the service's domain (probably init_t or custom domain). The correct type for executables in /usr/local/bin is 'bin_t'. The solution is to restore the SELinux context to the default for binaries using `restorecon -v /usr/local/bin/myapp` or changing it to bin_t. Option A is incorrect because permissions allow execution. Option C is unlikely because /usr/local/bin is in PATH. Option D is incorrect as user has execute permission.

Answer

The user myapp does not have read access to the binary.

Answer

The binary is located in a directory that is not in the systemd safe path.

Answer

The binary is not executable by myapp due to file permissions.

Question 3

A junior administrator needs to monitor system resource usage on a production server. Which TWO commands should the administrator use to check CPU and memory utilization in real-time? (Choose two.)

Accepted Answer

top. Top provides real-time CPU, memory, and process information. Free shows memory usage. Df checks disk space, lsof lists open files, and uptime shows system load but not resource utilization in real-time.

Answer

df

Answer

uptime

Answer

lsof

Question 4

An administrator is managing a server using systemd and needs to control services and units. Which THREE of the following are valid systemd commands for service management? (Choose three.)

Accepted Answer

systemctl mask. Systemctl is the primary systemd command; start, enable, and mask are valid subcommands. Service and chkconfig are legacy SysVinit commands.

Answer

service start

Answer

chkconfig on

Question 5

A system administrator is troubleshooting a server that is experiencing periodic slowdowns. The administrator runs the 'ps aux' command and notices a process named 'cpu_burn' that is consistently using over 90% CPU. The administrator wants to identify which user is running the process and then terminate it. The server runs Red Hat Enterprise Linux 8. Which command should the administrator use to determine the owner of the 'cpu_burn' process?

Accepted Answer

ps -eo pid,user,comm | grep [c]pu_burn. The 'ps -eo pid,user,comm' command outputs the PID, user, and command name for all processes, useful for identifying the owner of a specific process. Option A can show user but 'grep cpu_burn' will match other fields. Option B is correct as it directly greps the command name. Option C uses 'top' which is interactive and not efficient for scripting. Option D shows all processes filtered by user, but that doesn't help find the user.

Answer

ps -u cpu_burn

Answer

ps -ef | grep cpu_burn

Answer

top -bn1 | grep cpu_burn

Question 6

An administrator needs to schedule a backup script located at '/usr/local/bin/backup.sh' to run every Sunday at 2:30 AM. The server uses cron for task scheduling. The administrator currently has the following crontab entry: '30 2 * * 0 /usr/local/bin/backup.sh'. However, the administrator wants to verify that the cron job is configured correctly and will run as expected. Which of the following commands should the administrator use to list the current user's cron jobs and verify the entry?

Accepted Answer

crontab -l. The 'crontab -l' command lists the current user's crontab entries. Option A is correct. 'cron -l' is not a valid command. 'cat /var/spool/cron/crontabs/root' might work for root but not for a regular user, and the path varies. 'systemctl status cron' shows the cron service status, not the job list.

Answer

cat /var/spool/cron/crontabs/root

Answer

systemctl status cron

Answer

cron -l

Question 7

A server running Ubuntu 20.04 has a custom application that is started as a systemd service. The service often fails to start after a system reboot, although it can be started manually with 'systemctl start myapp' without errors. The administrator checks the service status after boot and sees 'Failed to start myapp.service: Unit is not loaded properly: Invalid argument'. Which of the following is the most likely cause of this issue?

Accepted Answer

The ExecStart line in the unit file contains an invalid parameter or malformed path.. The error 'Invalid argument' typically indicates a syntax error or invalid directive in the unit file. The most common cause is an incorrect path or syntax in the ExecStart line. Option A is correct. Option B would show a 'not found' error. Option C could be a cause but would produce a different error like 'unrecognized option'. Option D might cause a 'timeout' error.

Answer

The service binary does not exist at the specified path.

Answer

The service uses a Type=oneshot but no RemainAfterExit=yes is set.

Answer

The service file has a missing [Install] section.

Question 8

A system administrator is configuring centralized logging for a cluster of web servers. Each web server runs rsyslog and needs to forward its Apache access logs to a central log server at 192.168.1.100 over UDP port 514. The administrator adds the following line to /etc/rsyslog.conf on each web server: '*.* @192.168.1.100:514'. After restarting rsyslog, no logs appear on the central server. The administrator checks the network connectivity and finds that the central server is reachable and listening on UDP 514. Which additional configuration is most likely required on the web servers to forward the Apache logs?

Accepted Answer

Configure Apache to send access logs to syslog using the 'syslog' facility in the LogFormat directive.. The wildcard '*.*' forwards all logs, including Apache logs if they are sent to syslog. However, rsyslog by default only reads from its own sources; if Apache logs are written directly to a file and not via syslog, they won't be forwarded. The Apache module 'mod_log_config' can be configured to send logs to syslog using the 'syslog' facility. Option B is correct. Option A (el8 conf includes) is a file but not for Apache. Option C adds modular configs but doesn't address Apache. Option D (UDP vs TCP) might matter but the problem states UDP is used and listening.

Answer

Enable the 'imuxsock' module in rsyslog to listen on a Unix socket for Apache logs.

Answer

Create a configuration file in /etc/rsyslog.d/ with a more specific filter for Apache logs.

Answer

Change the forwarding protocol from UDP to TCP in both the sender and receiver.

Question 9

A Linux server is experiencing high I/O wait, as shown by the 'iostat -x' command: 'avg-cpu: %iowait=45' and '/dev/sda: await=120ms, %util=95%'. The server has 16 GB of RAM, and the administrator notices that the system is using a significant amount of swap: 'free -m' shows 4 GB of swap used out of 8 GB. The server runs a database application that performs many synchronous writes. The administrator wants to reduce I/O wait without adding physical memory. Which of the following kernel parameter changes is most likely to help by reducing the frequency of write operations to disk?

Accepted Answer

Increase vm.dirty_writeback_centisecs from 500 to 1000.. Increasing vm.dirty_writeback_centisecs (time between writeback flushes) allows more dirty pages to accumulate before being written, reducing write frequency and potentially merging writes, which can lower I/O wait if the I/O subsystem is efficient at handling larger writes. However, if the writeback interval is too high, it may increase burstiness. The other options: increasing dirty_ratio or dirty_background_ratio would allow more dirty pages in memory, which could temporarily reduce writes but might cause burstier writes and not reduce overall I/O wait. Decreasing dirty_writeback_centisecs would increase write frequency, likely worsening iowait. So Option C is the most plausible correct answer. Option D (swappiness) affects swap tendency, but swap usage indicates memory pressure; reducing swappiness might reduce swap but not directly address synchronous database writes.

Answer

Increase vm.dirty_ratio from 20 to 40.

Answer

Set vm.swappiness to 0.

Answer

Decrease vm.dirty_background_ratio from 10 to 5.

Question 10

Refer to the exhibit. A Linux administrator created a systemd service file for a custom script. When starting the service, it fails with 'Unit myservice.service entered failed state.' Which of the following is the most likely cause?

Accepted Answer

The ExecStart path is relative. The most likely cause is that the ExecStart path is relative. Systemd requires absolute paths for ExecStart directives; a relative path (e.g., `./script.sh` or just `script.sh`) will cause the unit to fail immediately because systemd cannot resolve the executable location. The error 'entered failed state' typically results from this path resolution failure.

Answer

The service type should be forking

Answer

The service file lacks an [Install] section

Answer

The Requires directive is missing

Question 11

A system administrator is troubleshooting why a user cannot execute a script in their home directory. Which THREE conditions could prevent execution? (Choose three.)

Accepted Answer

The script does not have the execute permission set for the user. Option C is correct because for a user to execute a script, the file must have the execute permission bit set for that user (or for the group or others, depending on the user's relationship to the file). Without the execute permission (e.g., `chmod +x`), the shell will refuse to run the script directly, returning a 'Permission denied' error.

Answer

The script is owned by a different user

Answer

The user's umask is set to 022

Question 12

A Linux administrator is tasked with adding a new 1TB hard drive to a server. The drive has been partitioned and formatted with ext4, resulting in the device /dev/sdb1. The administrator needs the drive to be mounted persistently at /data. After adding an entry to /etc/fstab, the administrator runs 'mount -a' and sees the error: 'mount: /data: mount point does not exist.' Which of the following should the administrator do first to resolve the issue?

Accepted Answer

Create the /data directory with mkdir. The error 'mount point does not exist' indicates that the directory /data has not been created on the filesystem. The mount command requires an existing directory to attach the device to. Creating the /data directory with mkdir resolves this, allowing mount -a to succeed.

Answer

Run mkfs.ext4 on /dev/sdb1

Answer

Reboot the server

Answer

Run fsck on /dev/sdb1

Question 13

Refer to the exhibit. A system administrator checks the status of the SSH service and sees the output shown. What is the most likely cause of the failure?

Accepted Answer

Another process is already listening on port 22.

Answer

The SSH service is disabled and needs to be enabled.

Answer

The SSH service is masked and cannot start.

Answer

The SSH configuration file has a syntax error.

Question 14

Refer to the exhibit. A network administrator is troubleshooting a failed network connection. Based on the journalctl output, what is the most likely cause?

Accepted Answer

The network interface eth0 is not physically connected.

Answer

The NetworkManager service is not running.

Answer

The network configuration file has an invalid IP address.

Answer

The DHCP server is unreachable.

Question 15

Refer to the exhibit. A system administrator notices that /var/log is nearly full. Which configuration change would resolve the issue and prevent recurrence?

Accepted Answer

Decrease the size threshold from 100M to 50M.

Answer

Add the 'delaycompress' option to the logrotate config.

Answer

Remove the postrotate script to avoid restarting syslog.

Answer

Increase the rotate count from 4 to 7.