Oracle 1z0-106 - Oracle Linux 8 Advanced System Administration

The/etc/sysconfigdirectory contains configuration files for various system services and applications. The content of this directory depends on which packages are installed on the system. Each package may provide one or more configuration files stored in/etc/sysconfigto control its behavior.

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 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 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 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.

Understanding logrotate:

The logrotate utility manages log files by rotating, compressing, and removing them based on configuration.

It helps prevent log files from consuming excessive disk space.

Option A: Rotating Log Files as Specified

Explanation:

logrotate rotates logs according to the specified criteria (size, time interval).

Rotation involves renaming the current log file and starting a new one.

Oracle Linux Reference:

Oracle® Linux 8: Managing Log Files-Using logrotate:

"The logrotate utility simplifies the administration of log files by automatically rotating, compressing, and removing log files."

Option C: Compressing Log Files

Explanation:

logrotate can compress old log files after rotation to save disk space.

Compression is typically done using gzip.

Oracle Linux Reference:

Oracle® Linux 8: Managing Log Files-Configuring logrotate:

"You can configure logrotate to compress rotated log files by using the compress option."

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):/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

Explanation of Answer A:When thechrootcommand is executed with/jail, the environment is changed to use/jailas its new root directory. Inside this environment, only the directories and files copied into/jailare accessible. Since/jaildoes not contain a/rootdirectory, the commandcd(which defaults to changing to the user's home directory) will fail, displayingNo such file or directory. Thepwdcommand shows the root of the chroot environment (/), andlsdisplays the contents of/jail, which includesbinandlib64.