Troubleshooting

A system administrator notices that a service named 'myapp' fails to start on a Linux server. The command 'systemctl status myapp' shows 'Active: failed (Result: exit-code)'. Which of the following is the BEST first step to diagnose the issue?

A user reports that they receive 'Permission denied' when trying to run a script located in their home directory. The script has permissions -rw-rw-r-- and is owned by the user. Which command should the user run to resolve the issue?

A Linux administrator is troubleshooting network connectivity. The server can ping its own IP address but cannot ping the default gateway. The output of 'ip route show' is: 'default via 10.0.0.1 dev eth0 proto static metric 100'. The output of 'ping -c 1 10.0.0.1' fails with 'Destination Host Unreachable'. Which of the following is the MOST likely cause?

A Linux server is running low on disk space in the /var partition. The administrator runs 'du -sh /var/log/*' and finds that /var/log/syslog is 10 GB. Which of the following is the BEST long-term solution to prevent recurrence?

A user cannot access a directory '/data/projects' even though they are in the 'projects' group. The directory permissions are 'drwxr-x---' and the group owner is 'projects'. Which command should the administrator run to grant the group write permission?

Which TWO commands can be used to display the amount of free and used memory on a Linux system?

Which THREE of the following are valid methods to troubleshoot a service that fails to start?

A user runs the ping command and receives the output shown in the exhibit. Which of the following is the MOST likely cause of the issue?

An administrator runs 'mount -a' and receives the error shown in the exhibit. The /home partition was recently removed and replaced with a new disk. Which of the following steps should the administrator take to resolve the issue?

A user reports that a Linux workstation fails to boot and displays 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. Which of the following is the most likely cause?

A Linux administrator notices that the system’s disk I/O performance has degraded significantly. Running 'iostat -x 1' shows high %util values on /dev/sda, but low await. Which of the following is the most likely issue?

During a security audit, a Linux administrator finds that an unauthorized service is listening on TCP port 4444. The service is not managed by systemd. Which of the following commands should the administrator use to identify the process and disable it?

A user reports that the /data directory is inaccessible. The Linux administrator runs the commands shown in the exhibit. Which of the following is the most likely cause of the issue?

A technician needs to troubleshoot a network connectivity issue on a Linux server. The server can ping its own IP address but cannot ping the default gateway. Which of the following is the most likely cause?

A Linux administrator suspects a memory leak in a process. Which TWO commands can be used to monitor memory usage over time for a specific process? (Choose two.)

A Linux server is experiencing intermittent connectivity issues. The administrator reviews the system logs and finds the following messages: 'NETDEV WATCHDOG: eth0: transmit queue 0 timed out'. Which THREE actions are likely to resolve this issue? (Choose three.)

A Linux administrator is troubleshooting a server that is running slowly. The 'sar -q' command shows a run queue length of 12 and a load average of 8.5. The CPU utilization is 90% idle. Which of the following is the most likely cause of the performance issue?

A user reports that a recently installed application fails to start. The application was installed via a shell script that added a repository and installed the package. The user runs 'ldd /usr/bin/app' and sees several 'not found' libraries. Which of the following is the MOST likely cause?

A Linux administrator notices that the system clock is consistently 5 minutes behind the actual time. The administrator runs 'timedatectl' and sees 'NTP service: active'. Which of the following commands should be used to force an immediate time synchronization?

An administrator is troubleshooting a web server that is not accessible from the internet. The server is running on port 80. Based on the iptables output, which of the following is the MOST likely reason?

A Linux administrator is troubleshooting a server that has become unresponsive. The administrator connects via IPMI and runs 'top' but the process list does not show any obvious CPU or memory hog. Which TWO commands could be used to identify I/O wait issues or disk bottlenecks? (Choose TWO.)

A database server running on Linux is experiencing high load. The administrator runs 'strace -p <pid>' and sees many 'epoll_wait' and 'futex' calls. Which THREE of the following are possible causes of the high load? (Choose THREE.)

A company runs a critical web application on a Linux server. The server has 16GB RAM and 4 CPU cores. Recently, users have reported intermittent timeouts and slow response times. The administrator logs in and runs 'top', which shows the web server process using 200% CPU (multi-threaded) and 2GB RAM. Free memory is 12GB, and swap usage is 0. The load average is 3.5, 4.0, 4.2. The administrator checks 'dmesg' and sees no OOM or hardware errors. The web server logs show many 'connection refused' errors during peak times. The application is configured to handle up to 500 concurrent connections. The administrator suspects the issue is related to the number of worker processes or threads. Which of the following is the BEST course of action to resolve the issue?

A Linux administrator receives reports that a web application hosted on the company's internal server is intermittently slow. The server runs CentOS 7 and hosts multiple virtual hosts. The administrator checks system resources and notices that the system's swap usage is high. Which of the following is the MOST likely cause of the performance issue?

A Linux engineer is troubleshooting a server that fails to boot. The server displays a message indicating 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. Which TWO actions should the engineer take to resolve this issue? (Choose TWO.)

Refer to the exhibit. A Linux administrator runs the netstat command to check listening services. The output shows that services are listening on ports 22, 80, and 443. Which of the following conclusions is correct based on the exhibit?

Drag and drop the steps to add a new user to the system in the correct order.

Drag and drop the steps to troubleshoot a network connectivity issue using common commands in the correct order.

Drag and drop the steps to configure SELinux to allow a custom web application to listen on port 8080 in the correct order.

Match each Linux filesystem to its typical use case.

Match each Linux package manager to its distribution family.

Match each Linux access control mechanism to its description.

A company needs to verify that the Apache HTTP server is running and see its current status along with recent log entries. Which command should be used?

After a power failure, a Linux server boots into emergency mode. The system logs indicate an unclean filesystem on /dev/sda2. Which command should the administrator run to repair the filesystem?

A system administrator installs a new application that is failing to write to its configuration file in /etc. SELinux is enforcing. Which command would show the relevant SELinux denials?

A user cannot access a file. The file has permissions 640 and is owned by root:root. The user is not root and not in the root group. Which command should the administrator use to allow the user to read the file?

A database server is experiencing slow queries. The administrator wants to analyze system memory usage. Which command shows memory usage in megabytes and includes information about buffers and cache?

A server is unable to resolve hostnames via DNS. The /etc/resolv.conf file appears correct. Which command can be used to test DNS resolution and display the full query path?

A Linux administrator needs to find large log files that may be consuming disk space. Which command should be used to locate files larger than 100MB in the /var/log directory?

After updating the kernel, the system fails to boot and displays 'Error 15: File not found' from GRUB. What is the most likely cause?

A Linux system is using systemd and a service fails to start. The administrator checks the service journal and sees: 'Failed to start service: Unit not found'. However, the service file exists in /etc/systemd/system/. What is the most likely cause?

A web server is experiencing high load. The administrator wants to identify the processes consuming the most CPU. Which TWO commands can be used to display real-time process CPU usage?

A system administrator suspects a disk failure. Which TWO commands can be used to check disk health and identify bad sectors?

A Linux server is not accepting SSH connections. The administrator wants to troubleshoot the issue. Which THREE actions should be taken?

The system is experiencing slow disk I/O. Based on the exhibit, which step should the administrator take to improve performance?

The system is a web server running Apache and MySQL. Based on the exhibit, which of the following is the most likely cause of the full disk?

The administrator wants to block the IP address shown in the exhibit. Which command should be used?

A system administrator notices that a Linux server is running low on disk space. Which command should be used to identify which directories are consuming the most space?

A user reports that a service fails to start with the error 'Permission denied'. The service runs under a non-root user. Which command should the administrator use to check if the service has the correct file permissions?

A Linux server experiences intermittent network connectivity issues. The administrator suspects a duplex mismatch. Which tool can best confirm duplex and speed settings on a network interface?

A technician needs to troubleshoot a system that is not booting. Which of the following is the most appropriate first step when using a rescue environment?

A database server is running slow. The administrator uses iostat and notices high await times on the disk. Which of the following best explains the implication of high await?

A system administrator is investigating why a particular process is not responding. They run strace on the process but get no output. What could be the most likely reason?

After a system update, a custom application no longer runs due to a shared library error. The library exists on the system but is in a non-standard path. Which environment variable should be checked or set to resolve this?

A system administrator needs to find out which process is using a particular file. Which command should they use?

A server is experiencing frequent kernel panics. The administrator wants to capture the crash dump for analysis. Which kernel parameter must be set to enable crash dumps?

A system administrator is troubleshooting a network issue where a server cannot reach external websites. The server can ping the default gateway and internal hosts. Which TWO commands should the administrator use to further diagnose the problem? (Choose TWO.)

A server crashed with a kernel panic. After reboot, the administrator wants to analyze the crash dump. Which THREE actions should be taken to ensure a valid core dump is captured and accessible? (Choose THREE.)

A user cannot log in to a Linux system via SSH, but the SSH service is running and network connectivity is fine. Which TWO commands should the administrator use to troubleshoot the issue? (Choose TWO.)

A user reports that their system fails to boot and displays a 'GRUB' prompt. Which command should be run first to attempt to load the operating system manually?

After editing the network configuration file /etc/sysconfig/network-scripts/ifcfg-ens33 on a CentOS system, the network service fails to restart with an error message. Which command should be used to display detailed error messages from the network service?

A Linux server experiences a kernel panic after a recent driver update. The system is still operational but unstable. Which command should be used to gather detailed information about the kernel modules currently loaded?

A user cannot start the Apache web service. The command 'systemctl start httpd' returns 'Failed to start httpd.service: Unit not found.' What is the most likely cause?

A system administrator notices that the root filesystem is at 95% capacity. Which command should be used to identify the directories consuming the most space?

A Linux server experiences a kernel panic during boot. You need to capture the panic message for analysis. Which kernel parameter should be added to the GRUB command line to ensure the panic message is displayed before the system halts?

A user attempts to run a command using sudo but receives 'user is not in the sudoers file. This incident will be reported.' Which file should be edited to grant the user sudo access?

A cron job that runs a backup script at 2 AM has not been executing. The syslog shows no errors from cron. What is the most likely reason the job is not running?

An application is being denied access to a file due to SELinux. Which command can be used to temporarily set the SELinux context of the file to match the expected type for the application?

Which TWO commands can be used to display the current kernel version on a Linux system?

Which TWO of the following are common causes of a system failing to boot? (Select two.)

Which THREE steps should be taken when diagnosing a network connectivity issue where a host cannot reach the internet but can ping the local gateway? (Select three.)

Refer to the exhibit. An administrator is troubleshooting an issue where services cannot write log files. Based on the output, which filesystem is most likely the cause?

Refer to the exhibit. A remote user is unable to SSH to the server. Based on the journalctl output, what is the most likely cause?

Refer to the exhibit. A user wants to execute the script 'script.sh' but receives a 'Permission denied' error. Which action should be taken to allow execution?

A company uses a Linux server running a web application. Users report that they cannot access the website. The administrator checks the web server status and finds it is not running. Which command should the administrator use to view the reason for the service failure?

A user is able to ping the Linux server but cannot connect via SSH. The SSH service is running and listening. Which configuration file should the administrator review FIRST?

A Linux system fails to boot and displays a kernel panic immediately after the GRUB menu. The administrator needs to boot into a rescue environment. Which GRUB boot parameter should the administrator add to the kernel line?

A user runs a command and receives the error 'bash: myapp: command not found'. The administrator confirms the binary exists in /usr/local/bin. Which environment variable should be checked?

A process is consuming excessive CPU. The administrator wants to reduce its priority. Which command should be used?

After a kernel update, the system boots but the network interface enp0s3 is not detected. The administrator verifies that the kernel module for the NIC is built for the new kernel. Which of the following should be done to ensure the module loads correctly?

A Linux service fails to start. Which command should the administrator use to examine recent system logs for error messages related to the service?

A server's root filesystem is 100% full according to df -h. Which command should the administrator use to locate large files?

A user reports that their home directory is missing after a system reboot. The /home partition is listed in /etc/fstab with an incorrect UUID. What is the most likely outcome?

A system administrator is troubleshooting a custom systemd service that fails to start. Which of the following commands should be used to diagnose the issue? (Choose two.)

A technician is troubleshooting a user's inability to execute a script. The script has execute permissions for the user. Which of the following could be causing the issue? (Choose two.)

A network administrator needs to diagnose connectivity issues from a Linux server to a remote host. Which of the following tools can provide information about the path and latency? (Choose three.)

The output of df -h shows the root filesystem at 100% capacity. Which of the following commands should the administrator run NEXT to identify the cause?

Given the journalctl output for the httpd service, which of the following is the most likely cause?

A Linux system fails to boot after a disk replacement. The administrator examines /etc/fstab and sees the above. What is the most likely result of this configuration?

A user cannot write to a directory that has permissions 755. The user is not the owner but belongs to the group. Which command would allow the user to write?

A system fails to boot after installing a new SATA disk. The BIOS recognizes the disk. What is the most likely cause?

A service fails to start and journalctl shows 'Permission denied'. What should the administrator check first?

A cron job runs a script that fails because the command 'myapp' is not found. The script works when run manually by the same user. What is the most likely cause?

A server shows /dev/sda1 mounted at / is 100% full in df -h, but du -sh / shows only 50% usage. What is the most likely explanation?

A newly configured DNS server is unable to resolve any queries from clients. The server is running and network connectivity is verified. What should the administrator check first?

A custom udev rule for a new USB device is not being applied. The rule file is correctly placed in /etc/udev/rules.d/ with .rules extension. What is the most likely cause?

During peak hours, a web server experiences timeouts. The kernel log shows 'possible SYN flooding'. Which kernel parameter should be increased to mitigate this?

After a kernel update, loading a proprietary kernel module fails with 'Invalid module format'. The module was built from source against the previous kernel. What is the most likely cause?

Which TWO commands can be used to check disk space usage on a Linux system?

Which THREE are valid methods to view logs in a systemd-based system?

Which TWO are standard methods to boot into rescue mode in a systemd-based Linux distribution?

Refer to the exhibit. A user reports that the /var directory is not accessible. The system administrator checks the logical volumes and notices that the 'var' logical volume is not activated. Which command should be used to activate it?

A Linux system administrator is troubleshooting a server that runs a web application. Users report that the web application occasionally returns 503 Service Unavailable errors. The Apache web server appears to be running (systemctl status httpd shows active). The server has 8GB RAM and runs multiple applications. The administrator runs free -m and sees that swap usage is at 75% while available memory is very low. The top output shows that a process named 'databased' is consuming 40% of memory. The databased process is not a core application and is not needed for the web server. The administrator wants to resolve the issue without restarting the server. What should the administrator do?

A system administrator is troubleshooting a network issue on a Linux server running CentOS 7. The server is unable to connect to the internet, but internal network connections work fine. The administrator checks the network configuration: the server has a static IP 192.168.1.100/24, default gateway 192.168.1.1, and DNS server 8.8.8.8. The administrator can ping the gateway but cannot ping 8.8.8.8. From the server, a traceroute to 8.8.8.8 stops at the gateway. The administrator also notices that the route table shows a default route via 192.168.1.1. What is the most likely cause?

A user reports that their system is unable to boot after a recent kernel update. The system displays a 'kernel panic' message. Which of the following is the MOST efficient way to boot into a previous kernel version?

A system administrator notices that the /var partition is full, causing log services to malfunction. Which command should be used to quickly reclaim space by removing compressed old log files?

A user cannot delete a file owned by another user on a shared filesystem. The file's permissions are 644, and the directory has permissions 755 with the sticky bit set. Which action would allow the user to delete the file?

A system administrator is troubleshooting a service that fails to start with the error 'Unit failed to load: Invalid argument'. The service file is located in /etc/systemd/system. What is the most likely cause?

A system administrator needs to identify which processes are consuming the most memory on a Linux server. Which two commands can be used? (Select TWO).

A user is unable to resolve hostnames on a Linux system. Which three configuration files should be checked? (Select THREE).

A Linux system fails to boot with the error 'No bootable device found'. Which two troubleshooting steps should be taken? (Select TWO).

A CentOS 7 web server experienced an abrupt power loss. Upon reboot, the httpd service fails to start. The administrator runs `systemctl status httpd` and sees 'Active: failed (Result: exit-code)'. The journal displays 'Permission denied: "/var/www/html/index.html"'. The file `/var/www/html/index.html` has permissions `-rw-r--r--` and is owned by `apache:apache`. SELinux is in enforcing mode. Which action should the administrator take to resolve the issue?

A system administrator is troubleshooting a server running Ubuntu 20.04 that cannot establish outbound SSH connections. The server can ping external IP addresses and resolve hostnames. The administrator tries `ssh user@remotehost` and gets 'Connection timed out'. The firewall (ufw) is active. Which step should be taken?

A file server running RHEL 8 uses NFS to export directories. Clients report that they cannot mount an NFS share. The server's firewall is configured but NFS-related services are enabled. The administrator checks `exportfs -v` and sees the export is listed. Which service must be added to the firewall to allow NFS?

A SysAdmin is investigating a server that has become unresponsive. The server was working fine, but after a recent update, it hangs during boot, showing 'A start job is running for /dev/mapper/rootvg-rootlv (xxs / no limit)'. This indicates a filesystem check is taking long. What is the most efficient way to skip the fsck and boot quickly?

A Linux server with the IP address 192.168.1.100 is unable to communicate with other hosts on the same subnet 192.168.1.0/24. The administrator can ping the loopback address, but pinging 192.168.1.1 (the default gateway) fails. The output of `ip a` shows the eth0 interface has the correct IP and netmask. Which troubleshooting step should be performed next?

A developer reports that a Docker container on a CentOS 7 host cannot connect to the internet. The host itself can access the internet. The container is started with default bridge network. The administrator checks iptables and sees the FORWARD policy is DROP. What is the most likely cause and solution?

A user is trying to log in to a Linux server via SSH but receives 'Permission denied (publickey,gssapi-keyex,gssapi-with-mic)'. The user's public key is in ~/.ssh/authorized_keys with proper permissions (600) and owned by the user. The server's sshd_config has 'PubkeyAuthentication yes' and 'PasswordAuthentication no'. What is the most likely additional cause?

A systems administrator is troubleshooting a server that fails to boot and displays the error: 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. Which TWO of the following are most likely causes? (Choose two.)

A technician runs the command `sudo lvdisplay /dev/vg_root/lv_root` and sees the output in the exhibit. The server fails to mount the root filesystem during boot. Which of the following should the technician do first?

A junior administrator reports that users cannot connect to a file server running Samba. The server is reachable via ping. Logs from the Samba service show: 'smbd: error while loading shared libraries: libgnutls.so.30: cannot open shared object file: No such file or directory'. The administrator confirms the package 'libgnutls' is installed. Which of the following is the most likely cause and solution?

Refer to the exhibit. A backup script fails every 5 minutes. Which is the most likely cause?

Refer to the exhibit. Users report they cannot SSH to the server. Based on the logs, what is the most likely cause?

Refer to the exhibit. An administrator can SSH to the server but cannot ping 10.0.0.1. What is the most likely cause?

Refer to the exhibit. The system log is not updating. What is the cause?

Refer to the exhibit. A user cannot access a web server, but another host on the same subnet can. What is the most likely cause?