Oracle 1z0-106 Oracle Linux 8 Advanced System Administration Exam Practice Test

Explanation of Answer A:Thenmcli con addcommand is used to create a new network connection namedeth2. The parameters specify the connection type (ethernet), the interface name (ifname eth2), and the connection name (con-name eth2), creating a new configuration for theeth2interface.

Explanation of Answer C:Theipv4.addressparameter assigns a static IPv4 address (192.168.0.5/24) to theeth2connection. Therefore, the connection will have this static IP once created.

Option D: anacron jobs may run only once a day.

Explanation:

Anacronis designed for systems that are not running continuously (e.g., desktops or laptops that may be powered off at night). It ensures that scheduled tasks are executed at the specified intervals.

Anacron jobs are defined with periods indays. The minimal unit of time for scheduling in Anacron isone day. Therefore, Anacron can schedule jobs to runonce a dayat most.

It is not intended for tasks that need to run multiple times per day.

Oracle Linux Reference:

Oracle® Linux 8: Scheduling Tasks- Section onAnacron Configuration Files:

"Anacron is used to run commands periodically with a frequency specified in days."

Option E: anacron jobs are used to run cron jobs if the system was powered off when they were scheduled to run.

Explanation:

Anacron complements Cron by ensuring thatscheduled jobs are not missedif the system is powered off or in standby mode at the time they were supposed to run.

When the system boots up, Anacron checks for any scheduled jobs that did not run and executes them accordingly.

This is particularly useful for laptops or desktops that are not always on.

Oracle Linux Reference:

Oracle® Linux 8: Scheduling Tasks- Section onUnderstanding Anacron:

"Anacron is designed to run commands periodically with specified frequency, but unlike cron, it does not assume that the system is running continuously."

Why Other Options Are Not Correct:

Option A:cron jobs may run only once a minute.

Explanation:

Cron allows scheduling tasks with a minimum granularity ofone minute. However, this means that tasks can be scheduled to runevery minute, not limited to only once a minute.

Multiple cron jobs can be scheduled to run at the same minute.

Therefore, the statement is misleading; cron jobs can runas frequently as every minute, but notonly once a minute.

Option B:All crontabs are held in the /etc/cron.d directory.

Explanation:

The /etc/cron.d directory is used for system-wide cron jobs provided by packages or administrators.

User-specific cron jobs are stored in /var/spool/cron/ or managed via the crontab command and not placed in /etc/cron.d.

Additionally, the system crontab file is /etc/crontab, and there are also directories like /etc/cron.hourly, /etc/cron.daily, etc.

Option C:The crond daemon looks for jobs only in /etc/crontab.

Explanation:

The crond daemon checks multiple locations for scheduled jobs:

User crontabs managed via the crontab -e command (stored in /var/spool/cron/).

System-wide crontab file (/etc/crontab).

The /etc/cron.d/ directory.

The /etc/cron.hourly/, /etc/cron.daily/, /etc/cron.weekly/, and /etc/cron.monthly/ directories.

Therefore, crond does not look for jobsonlyin /etc/crontab.

Conclusion:

OptionsDandEare correct because they accurately describe the characteristics and purposes of Anacron in the context of scheduling tasks on an Oracle Linux system.

Option C (Correct):If a device named/dev/hdbwith theide-diskdriver is discovered, a symbolic link/dev/sparediskwill be created, pointing to/dev/hdb.

Option D (Correct):TheKERNEL=="hdb"match specifies that the device will have the kernel device name/dev/hdb.

Option A (Incorrect):This is incorrect because existing symbolic links are not overwritten unless explicitly defined.

Option B (Incorrect):The device itself is not renamed to/dev/sparedisk; rather, a symbolic link is created.

Option E (Incorrect):The rule specifically requires bothKERNEL=="hdb"andDRIVER=="ide-disk"to match; it is not an either/or condition.

Option C (Correct):This command sequence first loads the 802.1q module needed for VLAN tagging, then creates a VLAN interface (eth0.800) on the base interface (eth0), assigns an IP address (10.135.1.120/24), and sets the VLAN interface up.

Option A, B, D (Incorrect):These options have syntactical errors or missing parameters that make them incorrect for setting up a fully functional and accessible VLAN interface.

Oracle Linux Reference:Refer to:

Oracle® Linux 8: Configuring VLANs

Option A (Correct):Boot parameters are set in/etc/default/grubunder theGRUB_CMDLINE_LINUXdirective. After modifying this file, thegrub2-mkconfigcommand must be run to apply changes.

Option C (Correct):The/boot/loader/entries/directory contains configuration files for each kernel version, which store the boot parameters separately.

Option B (Incorrect):Boot parameters specified at the GRUB command line are not persistent across reboots unless added to the configuration file.

Option D (Incorrect):Parameters set from the GRUB menu are temporary and do not apply to subsequent reboots.

Oracle Linux Reference:Refer to:

Oracle® Linux 8: Configuring GRUB2

Option C (Correct):The-k passpart of theauditctlcommand defines a keyword (pass) for the audit rule. This keyword helps in filtering and searching logs in the audit trail.

Option D (Correct):The-w /etc/passwd -p wpart of the command sets up a watch on the/etc/passwdfile for write (w) operations. This audit rule will generate a log entry every time there is a write operation to/etc/passwd.

Option A (Incorrect):This command does not write directly to/etc/audit/rules.d/audit.rules; it defines a rule in memory that could be saved to this file later.

Option B (Incorrect):The rule only logs write (w) operations; it does not log read operations.

Option E (Incorrect):The command does not directly cause a write to/etc/audit/audit.rules.

Oracle Linux Reference:Refer to:

Oracle® Linux 8: Auditing and System Logs

man auditctlfor details on audit rules and options.

Option B: journalctl -p err shows only error log level.

Explanation:

The -p or --priority option in journalctl filters messages by their priority level.

When specifying asingle priority level, journalctl shows messagesonlyat that level.

The priority levels, as per syslog standards, are:

0: emerg

1: alert

2: crit

3: err

4: warning

5: notice

6: info

7: debug

Therefore, journalctl -p err displays messages with priorityerr (3)only.

Oracle Linux Reference:

Oracle® Linux 8: Managing Log Files- Section onFiltering Output withjournalctl:

"Use the -p option to display messages from the journal that have a specific priority level."

Example:

# journalctl -p err

Option D: journalctl -k shows kernel logs since the last boot.

Explanation:

The -k or --dmesg option filters messages from the kernel, equivalent to the output of the dmesg command.

This option implies -b, which limits the output to messages from the current boot.

Therefore, journalctl -k displays kernel messages since the last boot.

Oracle Linux Reference:

Oracle® Linux 8: Managing Log Files- Section onViewing Kernel Messages:

"Use the journalctl -k command to display kernel messages since the last system boot."

Example:

# journalctl -k

Option E: journalctl -p 6 shows all info log level messages and above.

Explanation:

When specifying a single numeric priority, journalctl displays messages withthat priority level and higher priority levels(i.e., lower severity).

Priority levels are ordered from 0 (highest severity) to 7 (lowest severity).

Therefore, journalctl -p 6 shows messages with priorities:

0 (emerg)

1 (alert)

2 (crit)

3 (err)

4 (warning)

5 (notice)

6 (info)

This includesinfo level messages (6)and all higher priority messages.

Oracle Linux Reference:

Oracle® Linux 8: Managing Log Files- Section onFiltering Output with journalctl:

"When you specify a single priority level, journalctl shows messages at that level and higher severity."

Example:

# journalctl -p 6

Why Other Options Are Not Correct:

Option A:journalctl -bl -p err fails if journal persistence is not configured.

Explanation:

The -b option displays messages from the current boot. This works even if journal persistence isnotconfigured because the logs from the current boot are stored in volatile memory (/run/log/journal).

Therefore, the command doesnot failif journal persistence is not configured.

Oracle Linux Reference:

Oracle® Linux 8: Managing Log Files- Section onJournal Volatility:

"By default, the journal stores logs in volatile memory and does not persist logs across reboots unless persistent storage is configured."

Option C:journalctl -p notice..warning shows all messages from notice to warning log level since the last boot.

Explanation:

The -p option allows specifying arangeof priorities. However, the correct order for the range should be from thehigher priority (lower number)to thelower priority (higher number).

Also, the priorities should be specified in the correct sequence, and ranges are inclusive.

Moreover, journalctl by default shows messages from all boots unless limited by the -b option.

Therefore, without -b, it does not limit messages to "since the last boot," making the statement incorrect.

Correct Command:

To display messages fromwarning (4)tonotice (5), the command should be:

# journalctl -p warning..notice -b

But even then, the priorities need to be specified correctly, and the command in Option C is incorrect.

Conclusion:

OptionsB,D, andEare correct because they accurately describe the behavior of the journalctl command in filtering and displaying log messages based on priority levels and sources.

Option C (Correct):Thedmesg -Tcommand converts the timestamps in the kernel ring buffer messages to a human-readable format. The defaultdmesgoutput shows the timestamps in a raw format (seconds since the kernel started), while the-Toption translates these timestamps into a human-readable date and time.

Option A (Incorrect):The-toption is used to remove the timestamps entirely from the output.

Option B (Incorrect):The-xoption provides extended information about the message (e.g., facility, level).

Option D (Incorrect):The-Woption waits for new messages and does not convert timestamps to a human-readable format.

Oracle Linux Reference:Refer to:

man dmesgfor more details ondmesgoptions.

Option D (Correct):Creating an empty file named.autorelabelin the root directory tells SELinux to relabel the entire file system during the next reboot.

Option F (Correct):Thefixfiles -F onbootcommand schedules a full file system relabel on the next reboot.

Option A, B, C, E (Incorrect):These options do not correctly set the system to relabel on reboot.

Oracle Linux Reference:Refer to:

Oracle® Linux 8: SELinux Guide

Option B (Correct):Btrfs uses a copy-on-write mechanism for both data and metadata, which ensures that the file system is more resilient to crashes and data corruption.

Option E (Correct):Btrfs supports online resizing, meaning that you can change the size of a mounted Btrfs file system without unmounting it.

Option G (Correct):Btrfs automatically defragments files in the background to maintain performance.

Option A (Incorrect):While Btrfs does support mirroring, it is not strictly block device mirroring in the traditional sense like RAID; it uses a different approach to redundancy.

Option C (Incorrect):Btrfs is not a cluster file system; it is designed for local file systems.

Option D (Incorrect):While Btrfs can store small files efficiently, it is not its primary design goal compared to other file systems optimized specifically for small files.

Option F (Incorrect):Btrfs is a file system with integrated volume management capabilities but is not a general-purpose volume manager like LVM.

Oracle Linux Reference:Refer to:

Oracle® Linux 8: Btrfs File System

man btrfsfor features and management.

Explanation of Answer D:Theinitramfs(initial RAM filesystem) is a temporary filesystem loaded into memory during the boot process, containing essential drivers and utilities. The kernel usesinitramfsto load necessary drivers and modules required to access the root file system, particularly if it resides on a disk that requires special drivers.

Explanation of Answer E:Both thevmlinuz(the compressed Linux kernel image) and theinitramfsfile are located in the/bootdirectory. The bootloader, such as GRUB, reads these files from/bootto start the system.

GRUB 2 (GRand Unified Bootloader version 2) is a bootloader that is capable of loading a variety of free operating systems directly. It also supports chain-loading, which is the process of loading other bootloaders. This feature allows it to boot proprietary operating systems, such as Windows, by passing control to their respective bootloaders. This flexibility makes GRUB 2 a popular choice for dual-boot or multi-boot configurations.

Explanation of Answer D:GRUB 2 has the capability to understand multiple file systems (like ext2/3/4, Btrfs, XFS, etc.) and kernel executable formats. This capability means GRUB 2 does not rely on the physical location of a kernel on the disk to load an operating system. Instead, it reads the file system to locate the kernel file. This feature adds flexibility and ease in managing boot entries and reduces the complexity involved in locating kernels manually.

Option B (Correct):The-Ior--interpretoption inausearchconverts the numerical system call numbers into their corresponding text names, making the output easier to understand.

Option C (Correct):The-scoption specifies the system call by name (mkdir), which helps in finding audit logs related to that particular system call in text format.

Option A, D, E (Incorrect):These options do not specifically translate the numeric system call numbers into human-readable text. OptionAfilters by the numeric ID,Dis an invalid option, andEreverses the search order but does not affect the format.

Oracle Linux Reference:Refer to:

Oracle® Linux 8: Auditing and System Logs

man ausearchfor more details on audit search and interpretation commands.

Explanation of Answer C:The commanduptrack-remove --allremoves all currently applied Ksplice updates, effectively preventing them from being reapplied upon reboot.

Explanation of Answer E:Creating a file/etc/uptrack/disabledisables Ksplice Uptrack, preventing it from applying any updates at the next system reboot.

Explanation of Answer D:The entrypool pool.ntp.org offlinein the/etc/chrony.conffile specifies that thechronydservice should not automatically poll the NTP pool servers atpool.ntp.orguntil it is explicitly enabled by thechronyccommand. This setting is typically used in environments where the network is not always available (e.g., laptops or isolated systems) to avoid unnecessary polling.

To use a file as swap space, it must first be initialized with themkswapcommand. Theddcommand creates an empty file, butmkswapformats this file to be used as swap space. This command writes the necessary swap header to the file, making it recognizable by the system as a valid swap area.

Explanation of Answer D:After initializing the swap file withmkswap, you can optionally assign a label to the swap file using theswaplabelcommand. This is not strictly required, but it can be useful for identifying swap files, especially if you are using multiple swap devices.

Understanding AutoFS Behavior:

AutoFSautomatically mounts file systems when accessed and unmounts them after a period of inactivity (default is 5 minutes).

A file system remains mounted as long as it isactive, meaning processes are accessing files or directories within it.

Scenario Analysis:

First Session:

Changed to a directory under AutoFS control (mount point is active).

Second Session:

Changed to /etc (does not affect the first session).

Idle Time Expires:

AutoFS checks for idle mounts to unmount.

Implications:

The mount point remainsactivebecause the shell in the first session is in the AutoFS directory.

AutoFS willnotunmount the file system while it is active.

Oracle Linux Reference:

Oracle® Linux 8: Configuring File Systems-Using the Automounter:

"A file system remains mounted as long as there are open files or directories within it."

Correct Options:

Option B:The file system remains mounted until you log out from the first session.

Option E:The file system remains mounted until you switch to a directory outside the current mount point.

Why Other Options Are Incorrect:

Option A:Incorrect because the mount does not persist indefinitely; it's unmounted when no longer active.

Option C:Incorrect because the mount is still active; the timer does not cause unmounting in this case.

Option D:Incorrect because the second session does not influence the mount status in the first session.

Option B (Correct):Thefdisk -lcommand lists information about all available disks, including their sizes, partition tables, and partition details.

Option E (Correct):fdiskcannot handle disks larger than 2 TB because it is limited to the Master Boot Record (MBR) partitioning scheme. To manage larger disks (over 2 TB), the GUID Partition Table (GPT) is required, andfdiskdoes not fully support GPT.

Option A (Incorrect):fdiskdoes not support HFS (Hierarchical File System, used by macOS). It primarily supports MBR and has limited support for GPT.

Option C (Incorrect):fdiskdoes not support partitioning disks larger than 2 TB with GPT;gdiskorpartedshould be used instead.

Option D (Incorrect):fdiskdoes not divide logical devices into block disks called partitions; it operates on physical storage devices to create partitions.

Oracle Linux Reference:Refer to:

Oracle® Linux 8: Managing Disks and Partitions

man fdiskfor more details on the usage and limitations of thefdiskutility.