System Architecture

A system administrator notices that the server's clock is consistently off by several minutes. Which service should be used to synchronize the time with an external time source?

During boot, the kernel must mount the root filesystem. Which of the following is responsible for providing the kernel with the location of the root filesystem?

A server has two disk drives: /dev/sda (SSD) and /dev/sdb (HDD). The administrator wants to place frequently accessed files on the SSD for performance. Which approach best achieves this using Linux filesystem features?

A technician is troubleshooting a system that fails to boot with the error 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. What is the most likely cause?

Which hardware component uses a unique address to identify itself on the network at the data link layer?

A Linux system has two network interfaces: eth0 and eth1. The administrator wants to bond them for increased throughput. Which kernel module is required for bonding?

An administrator needs to ensure that a specific kernel module is loaded automatically at boot. Which file should be used to permanently load the module?

Which command displays information about the CPU, including model name, cache size, and flags?

A server with a udev rule fails to consistently assign a persistent network interface name. What is the most likely cause?

Which TWO of the following are valid methods to reduce boot time on a Linux system? (Select exactly 2.)

Which THREE of the following are characteristics of UEFI firmware compared to legacy BIOS? (Select exactly 3.)

Which TWO commands can be used to display the amount of free and used memory on a Linux system? (Select exactly 2.)

Refer to the exhibit. The system has a single disk with three partitions. Which partition contains the root filesystem?

Refer to the exhibit. How many SATA controllers are detected, and what is the connection speed of the SSD?

A company runs a critical database server on Linux. The server has a hardware RAID controller with two logical volumes: one for the operating system (LV1) and one for the database data (LV2). The server uses LVM on top of the RAID volumes. Recently, the database performance has degraded. The administrator suspects that the file system on LV2 is heavily fragmented. The server uses the ext4 filesystem. The administrator wants to check the fragmentation level and, if necessary, defragment the filesystem without unmounting it or causing downtime. However, ext4 does not support online defragmentation. What should the administrator do to minimize fragmentation impact while maintaining availability?

A Linux system administrator is tasked with setting up a new server that will host multiple virtual machines using KVM. The server has 64 GB of RAM and two physical CPUs, each with 8 cores (16 threads). The administrator needs to allocate resources efficiently. The VMs will have varying workloads. The administrator wants to ensure that the host system has enough resources for itself and that VMs can use all available CPU cores. Which approach should the administrator take to configure CPU allocation for the host and VMs?

A system administrator notices that a server with a freshly installed Linux system fails to boot with the error 'No bootable device found'. The server has a single SATA hard disk connected to the motherboard's SATA controller. Which of the following is the most likely cause of this issue?

Which TWO of the following are valid methods to change the default runlevel on a SysV init-based system?

Refer to the exhibit. A Linux system fails to boot with a kernel panic. The dmesg output shows the disk is detected and partitions are recognized. Which of the following is the most likely cause of the kernel panic?

A Linux administrator manages a server that runs a custom application requiring a specific kernel module to be loaded at boot. The server uses SysV init and has the module listed in /etc/modules. However, after a recent kernel update, the module fails to load automatically at boot. The administrator can manually load the module with 'modprobe <module>' after the system is running. The application depends on this module being loaded before any network services start. Which of the following actions should the administrator take to ensure the module loads automatically at the correct time during boot?

Arrange the steps to configure a firewall rule using iptables to allow SSH.

Match each ACL term to its meaning.

During the boot process, the system stops at a GRUB prompt. Which command should be typed to continue booting?

Which command displays the system's architecture (e.g., x86_64)?

What is stored in the first sector of a hard disk (Master Boot Record)?

A system administrator needs to create a new Logical Volume (LV) in an existing LVM setup. Which sequence of commands is correct?

A Linux system fails to boot with the error: 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. What is the most likely cause?

Which command can be used to check whether a specific kernel module is currently loaded?

A sysadmin wants to ensure a specific kernel module is automatically loaded at boot. Which method is considered best practice?

During boot, a sysadmin sees the message 'Buffer I/O error on device sda1, logical block 0'. What does this most likely indicate?

A system has a software RAID1 array (/dev/md0) with two disks: /dev/sda and /dev/sdb. Disk /dev/sda fails. Which command sequence will replace the failed disk with a new /dev/sdc without stopping the array?

Which TWO commands can display the UUID of block devices?

Which TWO files are used to configure kernel boot parameters in GRUB?

Which THREE of the following are valid systemd targets?

The system administrator wants to use the entire sdb disk as a single partition. Which command will partition sdb with a single partition occupying the whole disk?

Based on the exhibit, which statement is true?

A system administrator notices that the system boots to the graphical interface but wants to change it to boot to a non-graphical multi-user target. Which command will make this change persistent?

A technician needs to output only the kernel release number. Which command should be used?

A server configured with UEFI firmware and GPT partitioning fails to boot after a GRUB package update. The administrator suspects the bootloader is not correctly installed. Which command should be used to reinstall GRUB to the EFI system partition?

A system administrator needs to ensure that the httpd service starts automatically when the system enters the multi-user.target. Which command should be used?

A kernel module fails to load with the error 'modprobe: FATAL: Module xyz not found in directory /lib/modules/$(uname -r)'. What is the most likely cause?

Which directory contains information about hardware devices in a hierarchical structure, such as PCI devices and USB devices?

A system administrator wants to disable the graphical target and boot to the text mode multi-user.target permanently. Which command should they run?

After modifying the /etc/fstab file, an administrator runs the command mount -a and receives the error 'mount: /data: special device /dev/sdb1 does not exist'. What is the most likely issue?

Which command shows the amount of free and used memory in the system, including swap?

A system administrator needs to see the boot messages recorded by systemd-journald from the current boot. Which command is most appropriate?

Which TWO commands can be used to display information about the CPU(s) in a Linux system? (Choose two.)

Which TWO conditions would cause the boot process to fall back to the GRUB rescue shell? (Choose two.)

Which THREE of the following are valid runlevels in a traditional SysV init system? (Choose three.)

Refer to the exhibit. How many physical disks are detected by the kernel, and what are their sizes?

Refer to the exhibit. The system is unable to mount a filesystem that should be identified by UUID 1234-5678. The administrator checks /etc/fstab and finds the entry: UUID=1234-5678 /data ext4 defaults 0 2. What is the most likely cause of the mount failure?

Refer to the exhibit. What is the current default target?

A Linux system fails to boot after installing a new kernel. Which step should be taken first to recover the system?

A system administrator wants to ensure a service named 'app.service' starts automatically on boot in a systemd-based system. Which command should be used?

A server with UEFI firmware and GPT partitioning has a corrupted bootloader. Which command can be used to reinstall GRUB in UEFI mode?

Which file is used by GRUB to load the kernel at boot time?

An administrator runs 'lsmod' and sees a module with a usage count of 1. What does this indicate?

A system takes a long time to boot due to a service that fails to start. Which systemd command can be used to identify the service causing the delay?

Which directory contains the kernel modules for the currently running kernel?

To add a kernel parameter temporarily to the kernel command line at boot, what key should be pressed in the GRUB menu?

A system has multiple CPUs but only one is being used. Which file under /sys/ can be checked to verify CPU online status?

Which TWO of the following are valid methods to list currently loaded kernel modules?

Which TWO commands can be used to set the default boot target (runlevel) in systemd?

Which THREE of the following are valid sources to configure GRUB?

A system administrator notices that after updating the kernel, the system fails to boot. The administrator wants to boot the previous kernel. Which GRUB menu option should be selected?

A Linux system using systemd fails to reach the default target after a recent change. The administrator wants to boot into a minimal environment to troubleshoot. Which kernel parameter should be added at the GRUB prompt?

A system administrator needs to blacklist the kernel module 'pcspkr' to disable the PC speaker. Which is the correct method?

On a systemd-based system, which file is NOT used for system initialization?

Which systemd target corresponds to the traditional runlevel 3?

An administrator wants to add a kernel parameter 'quiet splash' to the default boot entry. Which file should be edited?

A system boots in UEFI mode, and the administrator wants to add a new kernel entry to the EFI boot manager. Which tool should be used?

After connecting a USB device, the system does not create a device node in /dev. Which command can be used to trigger udev to re-evaluate the device?

Which command displays information about currently loaded kernel modules?

Which TWO of the following are valid methods to view kernel messages on a systemd-based system?

Which THREE of the following are valid systemd targets?

Which TWO of the following are required for a system to boot using UEFI?

The system administrator wants to add a new swap partition on /dev/sdb2. After creating the partition, which command should be used to initialize it as swap?

The administrator wants the sshd service to start automatically at boot. Which command should be used?

A system administrator is responsible for a Linux server running a critical application. The server recently experienced an unplanned power outage. Upon rebooting, the system fails to reach the default target and drops into an emergency shell. The administrator notices that the root filesystem (/) is mounted read-only. The /etc/fstab file contains the following lines: UUID=abc123 / ext4 errors=remount-ro 0 1 UUID=def456 /home ext4 defaults 0 2 UUID=ghi789 none swap sw 0 0 The administrator suspects that the /home filesystem has a corrupt superblock and is causing the boot failure. The administrator needs to check and repair the /home filesystem without causing data loss. Which of the following is the correct course of action?

A system administrator suspects a failing power supply because the server randomly reboots. Which command can be used to check hardware health and event logs?

After a system upgrade, the server fails to boot with the error: 'ERROR: Failed to mount the real root device.' The root filesystem is on an LVM logical volume. Which recovery step is most appropriate?

Which TWO commands can be used to obtain information about the CPU architecture of a Linux system?

Which THREE of the following are valid systemd service unit types?

A junior admin is tasked with configuring network bonding on a Debian server with two Ethernet interfaces, eth0 and eth1. The goal is to provide link redundancy using active-backup mode. The admin edits /etc/network/interfaces and adds configuration for bond0 with slaves eth0 eth1, then runs 'ifup bond0'. However, the bond interface fails to come up and the error message indicates that the 'bond' kernel module is not loaded. The admin checks with 'lsmod | grep bonding' and finds no output. Which additional step is required to successfully bring up the bond interface? Options: A) Run 'modprobe bonding' before ifup, B) Use ifenslave directly after ifup, C) Reboot the system to load the module, D) Add 'auto bond0' in /etc/network/interfaces.

A small office server running Ubuntu 20.04 experiences a gradual time drift. The system clock loses about 2 minutes per week. The hardware clock (RTC) is maintained by the motherboard battery and appears accurate when checked manually. The sysadmin wants to ensure the system clock stays synchronized automatically. Which single action should be taken? Options: A) Run 'timedatectl set-ntp true' to enable systemd-timesyncd, B) Add 'hwclock --hctosys' to /etc/rc.local, C) Install and configure the ntp package with a pool server, D) Use 'cron' to run ntpdate every minute.

A data center server with two NICs (eth0 and eth1) is configured for network bonding in mode 1 (active-backup). The admin notices that after a cable pull on eth0, the bond interface fails over to eth1 as expected. However, when the cable is reconnected to eth0, the bond remains on eth1 indefinitely. The admin checks /proc/net/bonding/bond0 and sees that eth0 is marked as 'up' but not as 'active'. Which parameter is most likely missing from the bond configuration? Options: A) 'miimon=100' to enable link monitoring, B) 'downdelay=0', C) 'updelay=0', D) 'primary=eth0' to prefer eth0 as the active slave.

An administrator is migrating a legacy service from a SysV init system to a systemd unit. The service is a long-running daemon that forks once. The admin writes a unit file of Type=forking, sets PIDFile correctly, and enables the service. On the next reboot, the service starts but systemd reports that the service entered 'failed' state shortly after start, even though the process is running. The log shows: 'PID file /var/run/myservice.pid not readable (yet?) after start.' What is the most likely cause? Options: A) The service does not write its PID file quickly enough, B) The PIDFile path is wrong, C) The unit file should use Type=simple instead, D) The service needs a TimeoutStartSec increase.

A production server running CentOS 7 has multiple SCSI disks (sda, sdb, sdc) configured in a RAID5 array managed by mdadm (md0). The root filesystem is on md0. After a power failure, the server boots but drops into a rescue shell with the error: 'md: md0: cannot run array. Not enough devices online.' The admin checks with 'cat /proc/mdstat' and sees that only sda and sdb are spares (marked as (S)), sdc is missing. Which sequence of commands should the admin use to attempt recovery and bring the system to a functional state? Options: A) First run 'mdadm --manage /dev/md0 --add /dev/sdc', then 'mdadm --run /dev/md0'. B) Boot from a live CD, then run 'mdadm --assemble --scan' to reassemble. C) Run 'mdadm --stop /dev/md0', then 'mdadm --assemble /dev/md0 /dev/sda /dev/sdb /dev/sdc'. D) Run 'mdadm --run /dev/md0' to force start the array in degraded mode, then add sdc with 'mdadm --add' after system is up.

A Linux system with a custom kernel fails to boot after a new kernel is compiled and installed. The boot process stops at a prompt: 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. The root filesystem is on /dev/sda2 with ext4. The system has an initramfs generated with dracut. The admin can boot from a previous kernel. Which is the most appropriate next step to troubleshoot and fix the issue? Options: A) Rebuild the initramfs using 'dracut --force --kver' with the correct kernel version, B) Add 'root=/dev/sda2' to the kernel command line, C) Use 'mkinitrd' with the '--preload' option for ext4 module, D) Run 'ldd /sbin/init' to check for missing libraries.

Which TWO statements about GRUB 2 are correct?

Refer to the exhibit. The system has multiple SAS drives attached to this controller, but one of them is not detected during boot. Which command is most likely to provide information about the device detection order?

A system administrator is troubleshooting a Linux server that fails to boot. The server has a software RAID 1 configuration using mdadm, with the root filesystem located on /dev/md0. During boot, the system halts with the following error: 'VFS: Unable to mount root fs on unknown-block(0,0)'. The admin verifies that the BIOS recognizes all disks and that the RAID array was properly assembled prior to the last shutdown. The system was working after a recent kernel update, but now fails. Which of the following actions is the most likely solution?