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SUSE Linux Enterprise Server 15

Administration Guide

Covers system administration tasks like maintaining, monitoring and customizing an initially installed system.

Publication Date: September 24, 2021
About This Guide
Available Documentation
Giving Feedback
Documentation Conventions
Product Life Cycle and Support
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 For More Information
2 sudo
2.1 Basic sudo Usage
2.2 Configuring sudo
2.3 Common Use Cases
2.4 More Information
3 YaST Online Update
3.1 The Online Update Dialog
3.2 Installing Patches
3.3 Automatic Online Update
4 YaST
4.1 Advanced Key Combinations
5 YaST in Text Mode
5.1 Navigation in Modules
5.2 Advanced Key Combinations
5.3 Restriction of Key Combinations
5.4 YaST Command Line Options
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 Frequently Asked Questions
8 Live Kernel Patching with KLP
8.1 Advantages of Kernel Live Patching
8.2 Low-level Function of Kernel Live Patching
8.3 Activation of SLE Live Patching
8.4 Installing and Removing Patches
8.5 The klp Tool
8.6 Stuck Kernel Execution Threads
8.7 Patch Lifecycle
8.8 Scope of Kernel Live Patching Technology
8.9 Scope of SLE Live Patching
8.10 Interaction with the Support Processes
9 Transactional Updates
9.1 Limitations of Technical 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 For 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 For 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 Customization of systemd
15.6 Advanced Usage
15.7 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
22 Accessing File Systems with FUSE
22.1 Configuring FUSE
22.2 Mounting an NTFS Partition
22.3 For 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 For 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 For 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 For More Information
IV Services
30 Time Synchronization with NTP
30.1 Configuring an NTP Client with YaST
30.2 Manually Configuring NTP in the Network
30.3 Configure chronyd at Runtime Using chronyc
30.4 Dynamic Time Synchronization at Runtime
30.5 Setting Up a Local Reference Clock
30.6 Clock Synchronization to an External Time Reference (ETR)
31 The Domain Name System
31.1 DNS Terminology
31.2 Installation
31.3 Configuration with YaST
31.4 Starting the BIND Name Server
31.5 The /etc/named.conf Configuration File
31.6 Zone Files
31.7 Dynamic Update of Zone Data
31.8 Secure Transactions
31.9 DNS Security
31.10 For More Information
32 DHCP
32.1 Configuring a DHCP Server with YaST
32.2 DHCP Software Packages
32.3 The DHCP Server dhcpd
32.4 For More Information
33 Sharing File Systems with NFS
33.1 Overview
33.2 Installing NFS Server
33.3 Configuring NFS Server
33.4 Configuring Clients
33.5 For More Information
34 Samba
34.1 Terminology
34.2 Installing a Samba Server
34.3 Starting and Stopping Samba
34.4 Configuring a Samba Server
34.5 Configuring Clients
34.6 Samba as Login Server
34.7 Samba Server in the Network with Active Directory
34.8 Advanced Topics
34.9 For More Information
35 On-Demand Mounting with Autofs
35.1 Installation
35.2 Configuration
35.3 Operation and Debugging
35.4 Auto-Mounting an NFS Share
35.5 Advanced Topics
36 SLP
36.1 The SLP Front-End slptool
36.2 Providing Services via SLP
36.3 For More Information
37 The Apache HTTP Server
37.1 Quick Start
37.2 Configuring Apache
37.3 Starting and Stopping Apache
37.4 Installing, Activating, and Configuring Modules
37.5 Enabling CGI Scripts
37.6 Setting Up a Secure Web Server with SSL
37.7 Running Multiple Apache Instances on the Same Server
37.8 Avoiding Security Problems
37.9 Troubleshooting
37.10 For More Information
38 Setting Up an FTP Server with YaST
38.1 Starting the FTP Server
38.2 FTP General Settings
38.3 FTP Performance Settings
38.4 Authentication
38.5 Expert Settings
38.6 For More Information
39 Squid Caching Proxy Server
39.1 Some Facts about Proxy Servers
39.2 System Requirements
39.3 Basic Usage of Squid
39.4 The YaST Squid Module
39.5 The Squid Configuration File
39.6 Configuring a Transparent Proxy
39.7 Using the Squid Cache Manager CGI Interface (cachemgr.cgi)
39.8 Cache Report Generation with Calamaris
39.9 For More Information
40 Web Based Enterprise Management Using SFCB
40.1 Introduction and Basic Concept
40.2 Setting Up SFCB
40.3 SFCB CIMOM Configuration
40.4 Advanced SFCB Tasks
40.5 For More Information
V Troubleshooting
41 Help and Documentation
41.1 Documentation Directory
41.2 Man Pages
41.3 Info Pages
41.4 Online Resources
42 Gathering System Information for Support
42.1 Displaying Current System Information
42.2 Collecting System Information with Supportconfig
42.3 Submitting Information to Global Technical Support
42.4 Analyzing System Information
42.5 Gathering Information during the Installation
42.6 Support of Kernel Modules
42.7 For More Information
43 Common Problems and Their Solutions
43.1 Finding and Gathering Information
43.2 Boot Problems
43.3 Login Problems
43.4 Network Problems
43.5 Data Problems
43.6 IBM Z: Using initrd as a Rescue System
A An Example Network
B GNU Licenses
B.1 GNU Free Documentation License
List of Figures
3.1 YaST Online Update
3.2 YaST Online Update Configuration
5.1 Main Window of YaST in Text Mode
5.2 The Software Installation Module
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 SLES 15 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 NTP Configuration Window
30.2 Adding a Time Server
31.1 DNS Server Installation: Forwarder Settings
31.2 DNS Server Installation: DNS Zones
31.3 DNS Server Installation: Finish Wizard
31.4 DNS Server: Logging
31.5 DNS Server: Zone Editor (Basics)
31.6 DNS Server: Zone Editor (NS Records)
31.7 DNS Server: Zone Editor (MX Records)
31.8 DNS Server: Zone Editor (SOA)
31.9 Adding a Record for a Master Zone
31.10 Adding a Reverse Zone
31.11 Adding a Reverse Record
32.1 DHCP Server: Card Selection
32.2 DHCP Server: Global Settings
32.3 DHCP Server: Dynamic DHCP
32.4 DHCP Server: Start-Up
32.5 DHCP Server: Host Management
32.6 DHCP Server: Chroot Jail and Declarations
32.7 DHCP Server: Selecting a Declaration Type
32.8 DHCP Server: Configuring Subnets
32.9 DHCP Server: TSIG Configuration
32.10 DHCP Server: Interface Configuration for Dynamic DNS
32.11 DHCP Server: Network Interface and Firewall
33.1 NFS Server Configuration Tool
34.1 Determining Windows Domain Membership
34.2 Windows Explorer Advanced Attributes Dialog
34.3 Windows Explorer Directory Listing with Compressed Files
34.4 Adding a New Samba Share with Snapshotting Enabled
34.5 The Previous Versions tab in Windows Explorer
37.1 HTTP Server Wizard: Default Host
37.2 HTTP Server Wizard: Summary
37.3 HTTP Server Configuration: Listen Ports and Addresses
37.4 HTTP Server Configuration: Server Modules
38.1 FTP Server Configuration — Start-Up
42.1 HTML Report Generated by SCA Tool
42.2 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
31.1 Forwarding Options in named.conf
31.2 A Basic /etc/named.conf
31.3 Entry to Disable Logging
31.4 Zone Entry for example.com
31.5 Zone Entry for example.net
31.6 The /var/lib/named/example.com.zone File
31.7 Reverse Lookup
32.1 The Configuration File /etc/dhcpd.conf
32.2 Additions to the Configuration File
34.1 A CD-ROM Share
34.2 [homes] Share
34.3 Global Section in smb.conf
34.4 Using rpcclient to Request a Windows Server 2012 Share Snapshot
37.1 Basic Examples of Name-Based VirtualHost Entries
37.2 Name-Based VirtualHost Directives
37.3 IP-Based VirtualHost Directives
37.4 Basic VirtualHost Configuration
37.5 VirtualHost CGI Configuration
39.1 A Request With squidclient
39.2 Defining ACL Rules
42.1 Output of hostinfo When Logging In as root

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