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

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.

The530 Permission deniederror indicates that the user is not allowed to log in. In vsFTPd, if theUSERLIST_ENABLEoption is set toYESin/etc/vsftpd/vsftpd.conf, and theoracleuser is listed in/etc/vsftpd/user_list, that user is explicitly denied access to the FTP server.

Option C (Correct):Theall-squashoption in the/etc/exportsfile maps all user and group requests from remote systems to the anonymous user (nfsnobody) on the NFS server. However, because theanonuidandanongidoptions are specified with501, all incoming requests are explicitly mapped to the UID and GID of the unprivileged local user with UID 501 and GID 501. Thero(read-only) option allows all clients to mount/usr/shared/toolsas read-only.

Option A (Incorrect):This is incorrect because all clients can mount the directory, but all users' requests are squashed to UID 501. There is no exception for local 501 users.

Option B (Incorrect):The answer is incorrect because it incorrectly states "privileged local 501 user." The UID 501 is typically an unprivileged user.

Option D (Incorrect):Theall-squashoption does not override the UID and GID explicitly defined byanonuidandanongid. Instead, it maps all remote requests to these values.

Option E (Incorrect):Theanonuidandanongiddirectives are not ignored; they are explicitly used to map all requests to the specified UID and GID.

Oracle Linux Reference:For more information on NFS exports and options, refer to:

Oracle® Linux 8: Managing NFS and NIS

man exportsfor details on export options.

Explanation of Answer B:systemdis the first process to start (PID 1) after the Linux kernel has booted and is responsible for initializing the user space and managing system services throughout the system's runtime. It is also the last process to stop during shutdown.

Explanation of Answer C:systemdmaintains backward compatibility with older System V init scripts. It can run and manage these scripts, ensuring legacy services are supported while providing newer functionalities through nativesystemdunit files.

Explanation of Answer C:Thesscommand can be used to display all available internal TCP information, including established connections with detailed TCP metrics, which matches the output in Answer C.

Explanation of Answer D:Thesscommand can display listening ports (TCP in this case) with details like congestion control algorithms (cubic), which aligns with Answer D. The output indicates a listening TCP socket on port 80.

Understanding the Command:

$ podman run --name=oracleshell -it oraclelinux:8-slim

(Note: The image is likely oraclelinux:8-slim without a space.)

podman run:Creates and starts a new container.

--name=oracleshell:Assigns the name oracleshell to the container.

-it:Runs the container in interactive mode with a pseudo-TTY.

oraclelinux:8-slim:Specifies the image to use.

Option A: The container creates and starts an interactive shell.

Explanation:

The -it option runs the container interactively.

If no command is specified, it executes the default command in the image (usually /bin/bash).

This provides an interactive shell inside the container.

Oracle Linux Reference:

Oracle® Linux 8: Managing Containers-Running Containers Interactively:

"You can run a container in interactive mode using the -i and -t options together."

Option D: The container is created and started in a single command.

Explanation:

The podman run command handles both creation and starting of the container.

There's no need to create the container separately.

Oracle Linux Reference:

Oracle® Linux 8: Managing Containers-Creating and Running Containers:

"The podman run command creates and starts a container in one operation."

Why Other Options Are Incorrect:

Option B:The container does not need to pre-exist; podman run creates it if it doesn't exist.

Option C:If the image doesn't exist locally, podman will attempt to pull it from the registry.

Oracle Linux Reference:

Oracle® Linux 8: Managing Containers-Pulling Images:

"If you attempt to run a container with an image that does not exist locally, Podman automatically pulls the image from a registry."

Option E:The container is not removed upon exit unless the --rm option is used.

Oracle Linux Reference:

Oracle® Linux 8: Managing Containers-Automatically Removing Containers:

"Use the --rm option to automatically remove the container when it exits."

Conclusion:

Correct Options:A, D

Summary:The command creates and starts a new container named oracleshell and opens an interactive shell session inside it.

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):Theuseraddcommand with-mcreates a home directory for the user, and the-s /bin/bashoption assigns the Bash shell. However, no password is set when the user is created withuseraddunless explicitly done with thepasswdcommand afterward.

Option A (Incorrect):There is no mention of adding the user to thewheelgroup; theuseraddcommand does not imply this.

Option C (Incorrect):The command does not automatically set a password; it only creates the user account with the specified shell.

Option D (Incorrect):The-moption ensures that a home directory is created.

Oracle Linux Reference:Refer to:

Oracle® Linux 8: Managing Users and Groups

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.

Explanation of Answer D:The/etc/login.defsfile in Oracle Linux contains configuration settings related to user account policies, including password aging controls. This includes settings such asPASS_MAX_DAYS,PASS_MIN_DAYS, andPASS_WARN_AGE, which define the maximum number of days a password is valid, the minimum number of days between password changes, and the number of days before password expiration to warn users, respectively.

Explanation of Answer E:The/etc/login.defsfile also contains settings for the encryption method used to encrypt user passwords. TheENCRYPT_METHODparameter specifies the hashing algorithm, such as SHA512, that is used to encrypt user passwords stored in/etc/shadow.

Option A (Correct):A user private group (UPG) ensures that each user has their own unique group created with the same name and ID as the user.

Option E (Correct):The UPG model helps prevent other users from modifying files by default, as newly created files are assigned to the user’s unique group and not to a shared group.

Option B (Incorrect):UPG does not give the capability to create new group users; this is related to group management commands.

Option C (Incorrect):UPG does not providesudocapabilities;sudoconfiguration is managed separately.

Option D (Incorrect):UPGs do not limit reading files to group users by default; it depends on specific file permissions.

Oracle Linux Reference:Refer to:

Oracle® Linux 8: Managing Users and Groups

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.

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

The commandcryptsetup luksOpen /dev/xvdd1 cryptfsis used to open an encrypted LUKS partition. This command maps the encrypted block device/dev/xvdd1to a decrypted block device that is accessible under/dev/mapper/cryptfs.

Option A (Correct):This is correct because thecryptsetup luksOpencommand creates a device mapping under/dev/mapper/with the name specified (cryptfsin this case). This mapping allows you to access the encrypted content of/dev/xvdd1through the decrypted virtual device/dev/mapper/cryptfs.

Options B, C, D, E (Incorrect):These options are incorrect because they do not accurately reflect the standard behavior of thecryptsetup luksOpencommand. The device created will always be in the format/dev/mapper/whereis the alias specified in the command.

Oracle Linux Reference:For more information, refer to:

Oracle® Linux 8: Managing Storage Devices

man cryptsetupfor more details on theluksOpencommand and LUKS management.

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