sca_sles15 SUSE Certified Administrator in Enterprise Linux 15 Questions and Answers

The basic components of RPM are RPM Database and RPM Package Manager. The RPM Database is a collection of files that store information about installed packages on the system. It is located in /var/lib/rpm by default. The RPM Package Manager is a set of tools and libraries that allow you to install, uninstall, query, verify, and manage RPM packages. It includes commands such as rpm, zypper, yast2, etc. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-rpm.html#sec-rpm-components

To restrict access to your server via SSH to just a few specific users, you need to modify the AllowUsers option in the /etc/ssh/sshd_config file. This option specifies a list of user names or patterns that are allowed to log in via SSH. Any user name that does not match the list will be denied access. You need to restart the sshd service for the changes to take effect. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-ssh-server.html#sec-ssh-server-config

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 bash commands that result in a valid arithmetic expansion are:

• TOTAL=$[8/2]
• TOTAL=$((5+2))
• ((TOTAL++))

Arithmetic expansion is a bash feature that allows you to perform integer calculations and assign or use the result in a command or expression. There are two syntaxes for arithmetic expansion: [expression]and((expression)). The expression can contain variables, operators, parentheses, etc. The ((expression)) syntax can also be used without the $ sign for assignments or conditional tests. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-bash.html#sec-bash-arithmetic

For programs to leverage PolKit they are split into two separate processes. The statements below that are true regarding these two PolKit processes are:

• The Mechanism process runs in the System Context.
• The Policy Agent process runs in the User Session.

The Mechanism process is responsible for performing privileged actions on behalf of unprivileged users. It runs as root in the System Context and communicates with PolKit via D-Bus. The Policy Agent process is responsible for requesting authorization from users when they attempt to perform privileged actions. It runs as a normal user in the User Session and communicates with PolKit via D-Bus. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-polkit.html#sec-polkit-processes

The network interface type supported by SLES that is used for link aggregation is bond. Link aggregation is a technique that combines multiple physical network interfaces into one logical interface for increased bandwidth and redundancy. A bond interface can use different modes and options to balance traffic and handle failures. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-network-bonding.html

The file that contains the ntp configuration is /etc/ntp.conf. This file specifies the ntp server or peer addresses, synchronization options, access restrictions, logging settings, and other parameters for the ntp daemon (ntpd) that provides time synchronization services on a Linux system. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-ntp-config.html

Save a File in Vim / Vi #The command to save a file in Vim is :w.

To save the file without exiting the editor, switch back to normal mode by pressing Esc, type :w and hit Enter.

https://linuxize.com/post/how-to-save-file-in-vim-quit-editor/

The w command will save the current file without exiting Vim. It stands for write. The other commands are either invalid or will exit Vim after saving. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-vim.html#sec-vim-save

The command that allows you to create an alias command is alias. The alias command can be used to define a short name or abbreviation for another command or sequence of commands. The syntax of the alias command is alias name=‘command’. For example, alias c=‘clear’ will create an alias named c for the clear command. You can then type c to run the clear command. To remove an alias, you can use unalias name. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-bash.html#sec-bash-alias

The program systemd is the process with process ID 1. It is responsible for initializing the system in the required way. systemd is started directly by the kernel and resists signal 9, which normally terminates processes. All other programs are either started directly by systemd or by one of its child processes.

The system initialization system used in SLES 15 is systemd. It is a modern and powerful system and service manager that replaces the traditional init system. It provides faster boot times, better dependency handling, parallelization, and more features and capabilities. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-systemd-basics.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

When you launch yast2 without specifying a module name, the YaST Control Center appears. The YaST Control Center is a graphical interface that allows you to access various YaST modules for system administration and configuration tasks. You can browse through different categories of modules, such as Software, Hardware, System, Network Services, etc., and launch them by clicking on their icons. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-yast.html#sec-yast-control-center

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

The commands that could be used to determine the proper syntax for the cp command are man cp, cp --help, and info cp. These commands will display the manual page, help message, or info page for the cp command, respectively. They will provide information about the usage, options, arguments, examples, and other details of the cp command. The other commands are either invalid or unrelated to cp. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-cli-help.html

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 initrd file is an initial ramdisk image that contains the necessary drivers and tools to mount the root file system and start the boot process. It is usually located in the /boot directory along with the kernel image (vmlinuz). References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-boot-initrd.html

It is false that it is not possible to open more than one file in Vim without running a second instance. Vim supports multiple buffers, windows, and tabs that allow you to work with multiple files within one Vim session. You can use various commands and options to open, switch, split, close, and manipulate files in different ways. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-vim.html#sec-vim-multiple-files

The configuration files that have a format that is compatible with the system logging facility in SUSE Linux Enterprise are /etc/syslog.conf and /etc/rsyslog.conf. These files contain rules that specify how to filter and process log messages from different sources and destinations. The /etc/syslog.conf file is used by the traditional syslogd daemon, while the /etc/rsyslog.conf file is used by the more advanced rsyslogd daemon. SUSE Linux Enterprise uses rsyslogd by default, but it can also read /etc/syslog.conf for backward compatibility. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-syslog.html#sec-syslog-config