1z0-106 Oracle Linux 8 Advanced System Administration Questions and Answers

Option A (Correct):The/procfile system is a pseudo-file system that contains runtime system information (e.g., system memory, mounted devices, hardware configuration, etc.). Files such as/proc/meminfoand/proc/cpuinfoprovide detailed information about memory and CPUs, respectively.

Option C (Correct):The/sysfile system, also known as sysfs, provides a view of the kernel's device model. It contains information about system hardware, including CPUs and memory. For example,/sys/devices/system/cpu/contains directories and files that provide detailed information about each CPU.

Option B (Incorrect):The/sysfile system does not contain a list of running processes. Running processes are listed in the/procfile system, with each process having its own directory under/proc.

Option D (Incorrect):/procdoes not contain a list of network drivers specifically. Network driver information is available under/proc/net, but this does not equate to a list of drivers.

Option E (Incorrect):The/sysfile system does not contain a list of mounted devices. Mounted devices are listed in/proc/mountsor the/etc/mtabfile.

Oracle Linux Reference:For more details, see:

Oracle® Linux 8: The/procand/sysFile Systems.

Option B (Correct):Container applications are dependent on the host operating system's kernel because containers share the OS kernel, unlike virtual machines, which use a hypervisor. Compatibility of the host OS kernel version is required to run containers.

Option D (Correct):Podman, Buildah, and Skopeo are container tools for managing container applications. Podman runs containers without requiring a daemon like Docker, Buildah is used to build container images, and Skopeo is used for transferring container images. These tools can operate independently of one another, providing a flexible and modular approach to container management on Oracle Linux.

Option A (Incorrect):Container applications built on bare metal can run on virtual machines or cloud instances as long as the environment supports the container runtime.

Option C (Incorrect):Containers do not package the entire runtime stack; they include the application and its dependencies but rely on the host OS for the kernel.

Option E (Incorrect):Podman does not require a running daemon; one of its advantages over Docker is that it can run containers in rootless mode without needing a persistent daemon.

Oracle Linux Reference:Refer to:

Oracle® Linux 8: Podman and Containers Guide

man podman,man buildah,man skopeofor further details on these tools.

Option A (Correct):The configuration lineauthpriv.* /var/log/authwould direct all messages of theauthprivfacility (which includes sensitive authentication messages) to the/var/log/authfile. The log entries provided, which include authentication-related messages from PAM (pam_unix), would be logged due to this setting.

Option B (Incorrect):The*.emerg *setting logs emergency messages to all users, not specifically the provided log output.

Option C (Incorrect):This setting logs various non-authentication-related messages to/var/log/messages. It specifically excludesauthpriv.

Option D (Incorrect):This setting appears to be commented out and incorrect for the logging behavior described.

Option E (Incorrect):Thecron.*setting logs cron messages, unrelated to the provided authentication logs.

Oracle Linux Reference:Refer to:

Oracle® Linux 8: System Logging with rsyslog

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.

Option A (Correct):The rule is applied to both IPv4 and IPv6 packets. Theinettable is used for filtering both IPv4 and IPv6 traffic, and since the rule is added to theinettable, it affects both IP versions.

Option E (Correct):The rule drops TCP packets inbound on port 80. The rule specifies theinputchain in thefiltertable, and it drops (drop) all TCP traffic (tcp) destined for port 80 (dport 80), which means any incoming TCP traffic on port 80 will be dropped.

Option B (Incorrect):The command does not automatically update the configuration on disk; the rule is applied immediately in memory but does not persist across reboots unless explicitly saved.

Option C (Incorrect):The rule specifies TCP packets only, not all traffic. Therefore, it does not drop traffic for protocols other than TCP.

Option D (Incorrect):Although this statement is correct, it is less specific than Option A, which is more accurate because it mentions both IP versions.

Option F (Incorrect):The rule applies to inbound traffic, not outbound, so it does not drop outbound traffic.

Oracle Linux Reference:Refer to:

Oracle® Linux 8: Managing Firewall Rules with nftables

Explanation of Answer B:iostatis a tool used to monitor system input/output device loading by observing the time devices are active concerning their average transfer rates. The "Device Utilization Report" provides statistics about device utilization and throughput rates, which is critical in identifying performance bottlenecks.

Explanation of Answer E:iostatalso generates "CPU Utilization Reports." These reports provide data about how the CPU is utilized during input/output operations, showing the percentage of CPU time used for user processes, system processes, and the time the CPU remains idle.

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.

Explanation of Answer A:Thesysctl -wcommand is used to modify kernel parameters at runtime. It allows you to set the value of a specific parameter in the/proc/sysdirectory. For example,sysctl -w net.ipv4.ip_forward=1will enable IP forwarding by writing the value directly to the corresponding file in/proc/sys.

Explanation of Answer B:Using theechocommand to write values directly to specific files in the/proc/sysdirectory is another method to change kernel parameters dynamically for the running system. For instance,echo 1 > /proc/sys/net/ipv4/ip_forwardachieves the same effect as thesysctl -wcommand.

Understanding the Automounter Configuration:

/etc/auto.master:

/net -hosts

/- auto.direct ro

The /- auto.direct ro line indicates:

Mount Point Prefix:/ (direct mounts)

Map File:auto.direct

Global Mount Options:ro (read-only)

/etc/auto.direct:

/nfs1 host01:/export/share1

/nfs2 -sync host01:/export/share2

/nfs3 host02:/export/share3

/nfs1 and /nfs3:

No specific mount options in auto.direct.

Inherit the ro option from /etc/auto.master.

/nfs2:

Specifies -sync option in auto.direct.

Inherits ro from /etc/auto.master.

Mount options are ro,sync.

Mount Options Resolution:

Global Options (ro) apply to all entries unless overridden.

Per-Entry Options in auto.direct override or supplement global options.

Effective Mount Options:

/nfs1:

ro (from /etc/auto.master)

Default NFS options (async unless sync is specified)

/nfs2:

ro (from /etc/auto.master)

sync (specified in auto.direct)

/nfs3:

ro (from /etc/auto.master)

Default NFS options (async)

Oracle Linux Reference:

Oracle® Linux 8: Configuring File Systems-Automounter Configuration:

"Options specified in the master map apply to all entries in the map unless overridden by entries in the map itself."

NFS Default Options:

"By default, NFS mounts are asynchronous (async) unless the sync option is specified."

Conclusion:

/nfs1 and /nfs3:Mounted with ro,async.

/nfs2:Mounted with ro,sync.

Correct Option:A

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.

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 D (Correct):The commandsetfacl --modify user:user2:r-x my_directorysets an Access Control List (ACL) entry that givesuser2read (r) and execute (x) permissions onmy_directory. The execute (x) permission is required to allow navigation into the directory.

Option A (Incorrect):The--defaultoption would set the default ACL for future files or directories created withinmy_directory, not the directory itself.

Option B (Incorrect):This option gives only read (r) permission, but without execute (x) permission,user2cannot navigate into the directory.

Option C (Incorrect):The-xoption is used to remove an ACL entry, not modify it.

Option E (Incorrect):This modifies the ACL for the grouptestinstead of the useruser2.

Oracle Linux Reference:Refer to:

Oracle® Linux 8: Using Access Control Lists

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.

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.

Option A (Correct):/lib64/securityis a common directory where PAM (Pluggable Authentication Module) libraries are stored for 64-bit systems.

Option D (Correct):/lib/securityis another directory where PAM libraries are stored, usually on 32-bit systems or as a fallback for 64-bit systems.

Option B (Incorrect):/etc/pam.dcontains configuration files for PAM modules but does not store the modules themselves.

Option C (Incorrect):/usr/libis a general directory for libraries but does not specifically store PAM modules.

Option E (Incorrect):/var/libis typically used for variable state information and is not relevant for storing PAM modules.

Oracle Linux Reference:Refer to:

Oracle® Linux 8: Managing Authentication