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SUSE Linux Enterprise Server 15 SP3

Administration Guide

This guide covers system administration tasks like maintaining, monitoring and customizing an initially installed system.

Publication Date: January 21, 2022
Available documentation
Improving the documentation
Documentation conventions
I Common tasks
1 Bash and Bash scripts
1.1 What is the shell?
1.2 Writing shell scripts
1.3 Redirecting command events
1.4 Using aliases
1.5 Using variables in Bash
1.6 Grouping and combining commands
1.7 Working with common flow constructs
1.8 More information
2 sudo basics
2.1 Basic sudo usage
2.2 Configuring sudo
2.3 sudo use cases
2.4 More information
3 Using YaST
3.1 YaST interface overview
3.2 Useful key combinations
4 YaST in text mode
4.1 Navigation in modules
4.2 Advanced key combinations
4.3 Restriction of key combinations
4.4 YaST command line options
5 YaST online update
5.1 The online update dialog
5.2 Installing patches
5.3 Viewing retracted patches
5.4 Automatic online update
6 Managing software with command line tools
6.1 Using Zypper
6.2 RPM—the package manager
7 System recovery and snapshot management with Snapper
7.1 Default setup
7.2 Using Snapper to undo changes
7.3 System rollback by booting from snapshots
7.4 Enabling Snapper in user home directories
7.5 Creating and modifying Snapper configurations
7.6 Manually creating and managing snapshots
7.7 Automatic snapshot clean-up
7.8 Showing exclusive disk space used by snapshots
7.9 Frequently asked questions
8 Live kernel patching with KLP
8.1 Advantages of Kernel Live Patching
8.2 Kernel Live Patching overview
8.3 Activating Kernel Live Patching using YaST
8.4 Activating Kernel Live Patching from the command line
8.5 Performing Kernel Live Patching
8.6 Troubleshooting Kernel Live Patching issues
9 Transactional updates
9.1 Limitations of technology preview
9.2 Enabling transactional-update
9.3 Managing automatic updates
9.4 The transactional-update command
9.5 Troubleshooting
10 Remote graphical sessions with VNC
10.1 The vncviewer client
10.2 Remmina: the remote desktop client
10.3 Configuring one-time sessions on the VNC server
10.4 Configuring persistent VNC server sessions
10.5 Configuring encryption on the VNC server
11 File copying with RSync
11.1 Conceptual overview
11.2 Basic syntax
11.3 Copying files and directories locally
11.4 Copying files and directories remotely
11.5 Configuring and using an rsync server
11.6 More information
II Booting a Linux system
12 Introduction to the boot process
12.1 Terminology
12.2 The Linux boot process
13 UEFI (Unified Extensible Firmware Interface)
13.1 Secure boot
13.2 More information
14 The boot loader GRUB 2
14.1 Main differences between GRUB legacy and GRUB 2
14.2 Configuration file structure
14.3 Configuring the boot loader with YaST
14.4 Differences in terminal usage on IBM Z
14.5 Helpful GRUB 2 commands
14.6 More information
15 The systemd daemon
15.1 The systemd concept
15.2 Basic usage
15.3 System start and target management
15.4 Managing services with YaST
15.5 Customizing systemd
15.6 Advanced usage
15.7 systemd timer units
15.8 More information
III System
16 32-bit and 64-bit applications in a 64-bit system environment
16.1 Runtime support
16.2 Kernel specifications
17 journalctl: Query the systemd journal
17.1 Making the journal persistent
17.2 journalctl: Useful switches
17.3 Filtering the journal output
17.4 Investigating systemd errors
17.5 Journald configuration
17.6 Using YaST to filter the systemd journal
17.7 Viewing logs in GNOME
18 update-alternatives: Managing multiple versions of commands and files
18.1 Overview
18.2 Use cases
18.3 Getting an overview of alternatives
18.4 Viewing details on specific alternatives
18.5 Setting the default version of alternatives
18.6 Installing custom alternatives
18.7 Defining dependent alternatives
19 Basic networking
19.1 IP addresses and routing
19.2 IPv6—the next generation Internet
19.3 Name resolution
19.4 Configuring a network connection with YaST
19.5 Configuring a network connection manually
19.6 Basic router setup
19.7 Setting up bonding devices
19.8 Setting up team devices for Network Teaming
19.9 Software-defined networking with Open vSwitch
20 Printer operation
20.1 The CUPS workflow
20.2 Methods and protocols for connecting printers
20.3 Installing the software
20.4 Network printers
20.5 Configuring CUPS with command line tools
20.6 Printing from the command line
20.7 Special features in SUSE Linux Enterprise Server
20.8 Troubleshooting
21 Graphical user interface
21.1 X window system
21.2 Installing and configuring fonts
21.3 GNOME configuration for administrators
21.4 Switching between Intel and NVIDIA Optimus GPUs with SUSE Prime
22 Accessing file systems with FUSE
22.1 Configuring FUSE
22.2 Mounting an NTFS partition
22.3 More information
23 Managing kernel modules
23.1 Listing loaded modules with lsmod and modinfo
23.2 Adding and removing kernel modules
24 Dynamic kernel device management with udev
24.1 The /dev directory
24.2 Kernel uevents and udev
24.3 Drivers, kernel modules and devices
24.4 Booting and initial device setup
24.5 Monitoring the running udev daemon
24.6 Influencing kernel device event handling with udev rules
24.7 Persistent device naming
24.8 Files used by udev
24.9 More information
25 Special system features
25.1 Information about special software packages
25.2 Virtual consoles
25.3 Keyboard mapping
25.4 Language and country-specific settings
26 Using NetworkManager
26.1 Use cases for NetworkManager
26.2 Enabling or disabling NetworkManager
26.3 Configuring network connections
26.4 NetworkManager and security
26.5 Frequently asked questions
26.6 Troubleshooting
26.7 More information
27 Power management
27.1 Power saving functions
27.2 Advanced configuration and power interface (ACPI)
27.3 Rest for the hard disk
27.4 Troubleshooting
28 VM guest
28.1 Adding and removing CPUs
29 Persistent memory
29.1 Introduction
29.2 Terms
29.3 Use cases
29.4 Tools for managing persistent memory
29.5 Setting up persistent memory
29.6 More information
IV Services
30 Service management with YaST
31 Time synchronization with NTP
31.1 Configuring an NTP client with YaST
31.2 Manually configuring NTP in the network
31.3 Configure chronyd at runtime using chronyc
31.4 Dynamic time synchronization at runtime
31.5 Setting up a local reference clock
31.6 Clock synchronization to an external time reference (ETR)
32 The domain name system
32.1 DNS terminology
32.2 Installation
32.3 Configuration with YaST
32.4 Starting the BIND name server
32.5 The /etc/named.conf configuration file
32.6 Zone files
32.7 Dynamic update of zone data
32.8 Secure transactions
32.9 DNS security
32.10 More information
33.1 Configuring a DHCP server with YaST
33.2 DHCP software packages
33.3 The DHCP server dhcpd
33.4 More information
34 SLP
34.1 The SLP front-end slptool
34.2 Providing services via SLP
34.3 More information
35 The Apache HTTP server
35.1 Quick start
35.2 Configuring Apache
35.3 Starting and stopping Apache
35.4 Installing, activating, and configuring modules
35.5 Enabling CGI scripts
35.6 Setting up a secure Web server with SSL
35.7 Running multiple Apache instances on the same server
35.8 Avoiding security problems
35.9 Troubleshooting
35.10 More information
36 Setting up an FTP server with YaST
36.1 Starting the FTP server
36.2 FTP general settings
36.3 FTP performance settings
36.4 Authentication
36.5 Expert settings
36.6 More information
37 Squid caching proxy server
37.1 Some facts about proxy servers
37.2 System requirements
37.3 Basic usage of Squid
37.4 The YaST Squid module
37.5 The Squid configuration file
37.6 Configuring a transparent proxy
37.7 Using the Squid cache manager CGI interface (cachemgr.cgi)
37.8 Cache report generation with Calamaris
37.9 More information
38 Web Based Enterprise Management using SFCB
38.1 Introduction and basic concept
38.2 Setting up SFCB
38.3 SFCB CIMOM configuration
38.4 Advanced SFCB tasks
38.5 More information
V Troubleshooting
39 Help and documentation
39.1 Documentation directory
39.2 Man pages
39.3 Info pages
39.4 Online resources
40 Gathering system information for support
40.1 Displaying current system information
40.2 Collecting system information with supportconfig
40.3 Submitting information to Global Technical Support
40.4 Analyzing system information
40.5 Gathering information during the installation
40.6 Support of kernel modules
40.7 More information
41 Common problems and their solutions
41.1 Finding and gathering information
41.2 Boot problems
41.3 Login problems
41.4 Network problems
41.5 Data problems
41.6 IBM Z: using initrd as a rescue system
A An example network
B GNU licenses
B.1 GNU free documentation license
List of Figures
4.1 Main window of YaST in text mode
4.2 The software installation module
5.1 YaST online update
5.2 Viewing retracted patches and history
5.3 YaST online update configuration
7.1 Boot loader: snapshots
10.1 vncviewer
10.2 Remmina's main window
10.3 Remote desktop preference
10.4 Quick-starting
10.5 Remmina viewing remote session
10.6 Reading path to the profile file
10.7 Remote administration
10.8 VNC session settings
10.9 Joining a persistent VNC session
13.1 Secure boot support
13.2 UEFI: secure boot process
14.1 GRUB 2 boot editor
14.2 Boot code options
14.3 Code options
14.4 Boot loader options
14.5 Kernel parameters
15.1 Services Manager
17.1 YaST systemd journal
19.1 Simplified layer model for TCP/IP
19.2 TCP/IP ethernet packet
19.3 Configuring network settings
19.4 wicked architecture
26.1 GNOME Network Connections dialog
26.2 firewalld zones in NetworkManager
30.1 YaST service manager
31.1 NTP configuration window
31.2 Adding a time server
32.1 DNS server installation: forwarder settings
32.2 DNS server installation: DNS zones
32.3 DNS server installation: finish wizard
32.4 DNS server: logging
32.5 DNS server: Zone Editor (Basics)
32.6 DNS server: Zone Editor (NS Records)
32.7 DNS server: Zone Editor (MX Records)
32.8 DNS server: Zone Editor (SOA)
32.9 Adding a record for a master zone
32.10 Adding a reverse zone
32.11 Adding a reverse record
33.1 DHCP server: card selection
33.2 DHCP server: global settings
33.3 DHCP server: dynamic DHCP
33.4 DHCP server: start-up
33.5 DHCP server: host management
33.6 DHCP server: chroot jail and declarations
33.7 DHCP server: selecting a declaration type
33.8 DHCP server: configuring subnets
33.9 DHCP server: TSIG configuration
33.10 DHCP server: interface configuration for dynamic DNS
33.11 DHCP server: network interface and firewall
35.1 HTTP server wizard: default host
35.2 HTTP server wizard: summary
35.3 HTTP server configuration: listen ports and addresses
35.4 HTTP server configuration: server modules
36.1 FTP server configuration — start-up
40.1 HTML report generated by SCA tool
40.2 HTML report generated by SCA appliance
List of Examples
1.1 A shell script printing a text
6.1 Zypper—list of known repositories
6.2 rpm -q -i wget
6.3 Script to search for packages
7.1 Example timeline configuration
14.1 Usage of grub2-mkconfig
14.2 Usage of grub2-mkrescue
14.3 Usage of grub2-script-check
14.4 Usage of grub2-once
15.1 List active services
15.2 List failed services
15.3 List all processes belonging to a service
18.1 Alternatives System of the java command
19.1 Writing IP addresses
19.2 Linking IP addresses to the netmask
19.3 Sample IPv6 address
19.4 IPv6 address specifying the prefix length
19.5 Common network interfaces and some static routes
19.6 /var/run/netconfig/resolv.conf
19.7 /etc/hosts
19.8 /etc/networks
19.9 /etc/host.conf
19.10 /etc/nsswitch.conf
19.11 Output of the command ping
19.12 Configuration for load balancing with Network Teaming
19.13 Configuration for DHCP Network Teaming device
20.1 Error message from lpd
20.2 Broadcast from the CUPS network server
21.1 Specifying rendering algorithms
21.2 Aliases and family name substitutions
21.3 Aliases and family name substitutions
21.4 Aliases and family names substitutions
24.1 Example udev rules
25.1 Entry in /etc/crontab
25.2 /etc/crontab: remove time stamp files
25.3 ulimit: Settings in ~/.bashrc
32.1 Forwarding options in named.conf
32.2 A basic /etc/named.conf
32.3 Entry to disable logging
32.4 Zone entry for example.com
32.5 Zone entry for example.net
32.6 The /var/lib/named/example.com.zone file
32.7 Reverse lookup
33.1 The configuration file /etc/dhcpd.conf
33.2 Additions to the configuration file
35.1 Basic examples of name-based VirtualHost entries
35.2 Name-based VirtualHost directives
35.3 IP-based VirtualHost directives
35.4 Basic VirtualHost configuration
35.5 VirtualHost CGI configuration
37.1 A request with squidclient
37.2 Defining ACL rules
40.1 Output of hostinfo when logging in as root

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