sca_sles15 SUSE Certified Administrator in Enterprise Linux 15 Questions and Answers

The term “action” means an action that defines where a log message ends up such as in a regular file or database table when referring to system logging in SUSE Linux Enterprise. An action is part of a rule that specifies how to process a log message based on its properties. An action can be one of the following types: file, pipe, shell, template, discard, stop, call, omusrmsg, ommysql, ompgsql, etc. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-syslog.html#sec-syslog-config-actions

If you are setting up a SLES 15 server that will require very large data volumes and journaling capabilities, the best choice for your data volumes is XFS. XFS is a high-performance and scalable file system that supports large files and file systems, online defragmentation and resizing, metadata checksums, and other features. XFS also provides journaling capabilities that ensure data consistency and integrity in case of system crashes or power failures. XFS is the default file system for data partitions in SLES 15. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-filesystems.html#sec-filesystems-xfs

The command that gives you a real-time view of the processes running on your system by giving you a continuously updated list is top. The top command will display various information about system performance and resource usage, such as CPU load, memory usage, swap usage, etc., as well as a list of processes sorted by CPU utilization by default. You can use various keyboard commands to interact with top and change its behavior and output. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-cli-processes.html#sec-cli-processes-top

The ip route show or ip r s commands will display the routing table on a Linux system. The routing table contains information about how to reach different network destinations. The cat /etc/sysconfig/routes command will display the static routes configuration file, which may not reflect the current routing table. The other commands are either invalid or unrelated to routing. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-network-routing.html

Assuming the default value for umask, which is 022, the permissions on new files would be set to 644 and the permissions on new directories would be set to 755. The umask value is subtracted from the base permissions of 666 for files and 777 for directories to determine the actual permissions. For example, 666 - 022 = 644 for files and 777 - 022 = 755 for directories. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-file-permissions.html#sec-file-permissions-umask

Subvolumes in BtrFS are like virtual filesystems that can be mounted separately with the -o subvol= option. They can also have different attributes and quotas. Subvolumes do not have to start with “@” character, although some default subvolumes use this convention. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-btrfs.html#sec-btrfs-subvolumes

The statements that are true regarding a daemon are:

A daemon will wait for some event to occur to trigger action on the part of the daemon.

A daemon process is launched by the system.

A daemon process is not associated with a terminal or a graphical environment.

A daemon is a background process that performs a specific service or task without user interaction. It usually starts at system boot and runs until the system shuts down. It does not have a controlling terminal or a graphical interface, and it often runs as root or a dedicated user. A daemon responds to events such as network requests, signals, timers, etc. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-daemons.html

By default, the VNC Client and the VNC server daemon use a self-signed SSL certificate for secure communications. The VNC server generates a self-signed certificate when it is started for the first time. The VNC Client will prompt the user to accept or reject the certificate when connecting to the server. Alternatively, the user can provide a custom certificate for the VNC server or disable encryption if desired. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-vnc-security.html

The openSUSE Leap version of Linux is designed for desktop power users and developers. It is a community-driven distribution that offers a stable and reliable operating system with cutting-edge software and tools. It is suitable for personal use, development, testing, and experimentation. It is not intended for high-availability or data center environments that require enterprise-level support and security. References: https://en.opensuse.org/Portal:Leap

The execute permission on a directory means you can use the cd command to change into the directory. It also means you can access the files and subdirectories inside the directory, if you have read permission on them. The execute permission does not affect the visibility or exportability of the directory. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-file-permissions.html

The -U option will install a package whether or not a previous version of the package is already installed. If a previous version exists, it will be upgraded. The -F option will install a package only if a previous version of the package is already installed. It will not install a new package. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-sw-cl.html#sec-rpm-commands

The recommended file system for data volumes is XFS. XFS is a high-performance and scalable file system that supports large files and file systems, online defragmentation and resizing, metadata checksums, and other features. XFS is the default file system for data partitions in SLES 15. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-filesystems.html#sec-filesystems-xfs

The command and options to remove repository number 4 are zypper rr 4. This command will remove the repository with the alias or number 4 from the system. It will also delete any associated cache data and metadata. To list the repositories on the system, you can use zypper lr or zypper repos. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-zypper.html#sec-zypper-repos

To make the third menu entry of your GRUB2 boot menu your default menu selection, you need to do the following tasks:

Edit the /etc/default/grub file and set GRUB_DEFAULT to 2

Run the grub2-mkconfig command

The /etc/default/grub file contains various settings for the GRUB2 boot loader, such as the default menu entry, the timeout value, the theme file, etc. The GRUB_DEFAULT setting can be set to a numeric value that corresponds to the menu entry index (starting from 0), or a string value that matches the menu entry title. The grub2-mkconfig command will generate a new /boot/grub2/grub.cfg file based on the settings in /etc/de fault/grub and other configuration files and scripts. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-grub2-config.html#sec-grub2-config-default

https://documentation.suse.com/sles/12-SP4/html/SLES-all/cha-security-acls.html

The three permissions available on posix file systems are read, write, and execute. The read permission allows the user to view the contents of a file or directory. The write permission allows the user to modify or delete a file or directory. The execute permission allows the user to run a file as a program or change into a directory. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-file-permissions.html#sec-file-permissions-types

The command that will take a foreground process and suspend it, and then place it in the background as a stopped job is Ctrl+Z. This keyboard shortcut will send a SIGTSTP signal to the foreground process group, which will stop its execution and return control to the shell. The shell will then display the job number and status of the stopped process. To resume the process in the background, you can use the bg command with the job number or % sign. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-cli-jobs.html

SUSE Linux Enterprise Server supports two different kinds of VNC sessions: One-time sessions that “live” as long as the VNC connection from the client is kept up, and persistent sessions that “live” until they are explicitly terminated.

5.1  One-time VNC Sessions

5.2  Persistent VNC Sessions

https://documentation.suse.com/sles/11-SP4/html/SLES-all/cha-vnc.html#:~:text=SUSE%20Linux%20Enterprise%20Server%20supports,until%20they%20are%20explicitly%20terminated .

The command that is used to ensure an ext3 file system is checked every 50 times it is mounted is tune2fs. The tune2fs command can be used to adjust various parameters of an ext2, ext3, or ext4 file system. The -c option can be used to set the maximum number of mounts between two file system checks. For example, tune2fs -c 50 /dev/sda1 will set the check interval to 50 mounts for /dev/sda1. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-tune2fs.html