Red Hat Enterprise Linux 8

1 Red Hat Enterprise Linux 8 configuring basic system settingsA guide to configuring basic system settings in Red Hat Enterprise Linux 8 Last Updated: 2023-01-17 Red Hat Enterprise Linux 8 configuring basic system settingsA guide to configuring basic system settings in Red Hat Enterprise Linux 8 Legal NoticeCopyright 2023 Red Hat, text of and illustrations in this document are licensed by Red Hat under a Creative CommonsAttribution Share Alike Unported license ("CC-BY-SA"). An explanation of CC-BY-SA isavailable In accordance with CC-BY-SA, if you distribute this document or an adaptation of it, you mustprovide the URL for the original Hat, as the licensor of this document, waives the right to enforce, and agrees not to assert,Section 4d of CC-BY-SA to the fullest extent permitted by applicable Hat, Red Hat Enterprise Linux , the Shadowman logo, the Red Hat logo, JBoss, OpenShift,Fedora, the Infinity logo, and RHCE are trademarks of Red Hat, Inc.

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3 The titlefocuses on: basic tasks that a system administrator needs to do just after the operating system hasbeen successfully installed, installing software with yum, using systemd for service management,managing users, groups and file permissions, using chrony to configure NTP, working with Python 3and ..Table of ContentsMAKING OPEN SOURCE MORE INCLUSIVEPROVIDING FEEDBACK ON RED HAT DOCUMENTATIONCHAPTER 1. PREPARING A CONTROL NODE AND MANAGED NODES TO USE RHEL SYSTEM INTRODUCTION TO RHEL SYSTEM RHEL SYSTEM ROLES PREPARING A CONTROL PREPARING A MANAGED VERIFYING ACCESS FROM THE CONTROL NODE TO MANAGED NODESCHAPTER 2. CHANGING BASIC ENVIRONMENT configuring THE DATE AND Displaying the current date and configuring THE SYSTEM configuring THE KEYBOARD CHANGING THE LANGUAGE USING DESKTOP ADDITIONAL RESOURCESCHAPTER 3. configuring AND MANAGING network configuring THE network AND HOST NAME IN THE GRAPHICAL INSTALLATION configuring A STATIC ETHERNET CONNECTION USING configuring A DYNAMIC ETHERNET CONNECTION USING configuring A STATIC ETHERNET CONNECTION USING MANAGING NETWORKING IN THE RHEL WEB MANAGING NETWORKING USING RHEL SYSTEM ADDITIONAL RESOURCESCHAPTER 4.

4 REGISTERING THE SYSTEM AND MANAGING REGISTERING THE SYSTEM AFTER THE REGISTERING SUBSCRIPTIONS WITH CREDENTIALS IN THE WEB REGISTERING A SYSTEM USING RED HAT ACCOUNT ON REGISTERING A SYSTEM USING AN ACTIVATION KEY ON REGISTERING RHEL 8 USING THE INSTALLER GUICHAPTER 5. MAKING SYSTEMD SERVICES START AT BOOT ENABLING OR DISABLING MANAGING SERVICES IN THE RHEL WEB CONSOLECHAPTER 6. configuring SYSTEM ENABLING THE FIREWALLD MANAGING FIREWALL IN THE RHEL 8 WEB MANAGING BASIC SELINUX ENSURING THE REQUIRED STATE OF SWITCHING SELINUX MODES IN THE RHEL 8 WEB ADDITIONAL RESOURCESCHAPTER 7. GETTING STARTED WITH MANAGING USER MANAGING ACCOUNTS AND GROUPS USING COMMAND LINE SYSTEM USER ACCOUNTS MANAGED IN THE WEB ADDING NEW ACCOUNTS USING THE WEB CONSOLECHAPTER 8. DUMPING A CRASHED KERNEL FOR LATER WHAT IS KDUMP91011111212141617171717181921222223 2527293031323233343536383838414142424344 44464647474949 Table of Contents1.

5 configuring KDUMP MEMORY USAGE AND TARGET LOCATION IN WEB KDUMP USING RHEL SYSTEM ADDITIONAL RESOURCESCHAPTER 9. RECOVERING AND RESTORING A SETTING UP USING A REAR RESCUE IMAGE ON THE 64-BIT IBM Z ARCHITECTURECHAPTER 10. TROUBLESHOOTING PROBLEMS USING LOG SERVICES HANDLING SYSLOG SUBDIRECTORIES STORING SYSLOG INSPECTING LOG FILES USING THE WEB VIEWING LOGS USING THE COMMAND ADDITIONAL RESOURCESCHAPTER 11. ACCESSING THE RED HAT OBTAINING RED HAT SUPPORT THROUGH RED HAT CUSTOMER TROUBLESHOOTING PROBLEMS USING SOSREPORTCHAPTER 12. MANAGING SOFTWARE SOFTWARE MANAGEMENT TOOLS IN RHEL APPLICATION SEARCHING FOR SOFTWARE Searching packages with Listing packages with Listing repositories with Displaying package information with Listing package groups with Specifying global expressions in YUM INSTALLING SOFTWARE Installing packages with Installing a package group with Specifying a package name in YUM UPDATING SOFTWARE Checking for updates with Updating a single package with Updating a package group with Updating all packages and their dependencies with Updating security-related packages with Automating software Installing DNF DNF Automatic configuration Enabling DNF Overview of the systemd timer units included in the dnf-automatic UNINSTALLING SOFTWARE Removing packages with Removing a package group with Specifying a package name in

6 YUM MANAGING SOFTWARE PACKAGE Listing package groups with Installing a package group with Removing a package group with Specifying global expressions in YUM HANDLING PACKAGE MANAGEMENT HISTORY495152535354575757575859606060626 2626263636464646565656667676768686868696 969707273737374747475757676 Red Hat Enterprise Linux 8 configuring basic system settings2.. Listing transactions with Reverting transactions with Repeating transactions with Specifying global expressions in YUM MANAGING SOFTWARE Setting YUM repository Adding a YUM Enabling a YUM Disabling a YUM configuring Viewing the current YUM Setting YUM main Using YUM Managing YUM Enabling YUM Disabling YUM plug-insCHAPTER 13. INTRODUCTION TO ADDITIONAL RESOURCESCHAPTER 14. MANAGING SYSTEM SERVICES WITH LISTING SYSTEM DISPLAYING SYSTEM SERVICE STARTING A SYSTEM STOPPING A SYSTEM RESTARTING A SYSTEM ENABLING A SYSTEM DISABLING A SYSTEM SERVICECHAPTER 15.

7 WORKING WITH SYSTEMD VIEWING THE DEFAULT VIEWING THE TARGET CHANGING THE DEFAULT CHANGING THE DEFAULT TARGET USING A SYMBOLIC CHANGING THE CURRENT BOOTING TO RESCUE BOOTING TO EMERGENCY MODECHAPTER 16. SHUTTING DOWN, SUSPENDING, AND HIBERNATING THE SYSTEM SHUTTING DOWN THE SYSTEM USING THE SHUTDOWN SHUTTING DOWN THE SYSTEM USING THE SYSTEMCTL RESTARTING THE SUSPENDING THE HIBERNATING THE OVERVIEW OF THE POWER MANAGEMENT COMMANDS WITH SYSTEMCTLCHAPTER 17. WORKING WITH SYSTEMD UNIT INTRODUCTION TO UNIT UNIT FILE IMPORTANT [UNIT] SECTION IMPORTANT [SERVICE] SECTION IMPORTANT [INSTALL] SECTION CREATING CUSTOM UNIT FILES76777778787879798080808080818181838 4858586888990919293939394959696979898989 999100100101102102102103104105105 Table of Contents3.. CREATING A CUSTOM UNIT FILE BY USING THE SECOND INSTANCE OF THE SSHD CONVERTING SYSV INIT SCRIPTS TO UNIT FINDING THE SYSTEMD SERVICE FINDING THE SYSTEMD SERVICE FINDING DEFAULT TARGETS OF THE FINDING FILES USED BY THE MODIFYING EXISTING UNIT EXTENDING THE DEFAULT UNIT OVERRIDING THE DEFAULT UNIT CHANGING THE TIMEOUT MONITORING OVERRIDDEN WORKING WITH INSTANTIATED IMPORTANT UNIT ADDITIONAL RESOURCESCHAPTER 18.

8 OPTIMIZING SYSTEMD TO SHORTEN THE BOOT EXAMINING SYSTEM BOOT PERFORMANCEA nalyzing overall boot timeAnalyzing unit initialization timeIdentifying critical A GUIDE TO SELECTING SERVICES THAT CAN BE SAFELY ADDITIONAL RESOURCESCHAPTER 19. INTRODUCTION TO MANAGING USER AND GROUP INTRODUCTION TO USERS AND configuring RESERVED USER AND GROUP USER PRIVATE GROUPSCHAPTER 20. MANAGING USER ACCOUNTS IN THE WEB SYSTEM USER ACCOUNTS MANAGED IN THE WEB ADDING NEW ACCOUNTS USING THE WEB ENFORCING PASSWORD EXPIRATION IN THE WEB TERMINATING USER SESSIONS IN THE WEB CONSOLECHAPTER 21. MANAGING USERS FROM THE COMMAND ADDING A NEW USER FROM THE COMMAND ADDING A NEW GROUP FROM THE COMMAND ADDING A USER TO A SUPPLEMENTARY GROUP FROM THE COMMAND CREATING A GROUP DIRECTORYCHAPTER 22. EDITING USER GROUPS USING THE COMMAND PRIMARY AND SUPPLEMENTARY USER LISTING THE PRIMARY AND SUPPLEMENTARY GROUPS OF A CHANGING THE PRIMARY GROUP OF A ADDING A USER TO A SUPPLEMENTARY GROUP FROM THE COMMAND REMOVING A USER FROM A SUPPLEMENTARY CHANGING ALL OF THE SUPPLEMENTARY GROUPS OF A USERCHAPTER 23.

9 MANAGING SUDO USER AUTHORIZATIONS IN GRANTING SUDO ACCESS TO A ENABLING UNPRIVILEGED USERS TO RUN CERTAIN COMMANDSCHAPTER 24. CHANGING AND RESETTING THE ROOT CHANGING THE ROOT PASSWORD AS THE ROOT USER107108109109110110112113114115115116 1171181191191191191191201241251251251261 2712712712812913113113113213313513513513 6137137138140140141142144144 Red Hat Enterprise Linux 8 configuring basic system settings4.. CHANGING OR RESETTING THE FORGOTTEN ROOT PASSWORD AS A NON-ROOT RESETTING THE ROOT PASSWORD ON BOOTCHAPTER 25. MANAGING FILE BASE FILE USER FILE-CREATION MODE DEFAULT FILE CHANGING FILE PERMISSIONS USING SYMBOLIC CHANGING FILE PERMISSIONS USING OCTAL VALUESCHAPTER 26. MANAGING THE DISPLAYING THE CURRENT VALUE OF THE DISPLAYING THE DEFAULT BASH SETTING THE UMASK USING SYMBOLIC SETTING THE UMASK USING OCTAL CHANGING THE DEFAULT UMASK FOR THE NON-LOGIN CHANGING THE DEFAULT UMASK FOR THE LOGIN CHANGING THE DEFAULT UMASK FOR A SPECIFIC SETTING DEFAULT PERMISSIONS FOR NEWLY CREATED HOME DIRECTORIESCHAPTER 27.

10 USING DNSTAP IN RECORDING DNS QUERIES USING DNSTAP IN RHELCHAPTER 28. MANAGING THE ACCESS CONTROL DISPLAYING THE CURRENT ACCESS CONTROL SETTING THE ACCESS CONTROL LISTCHAPTER 29. USING THE CHRONY SUITE TO CONFIGURE INTRODUCTION TO CHRONY USING CHRONYC TO CONTROL MIGRATING TO Migration scriptCHAPTER 30. USING MANAGING CHECKING IF CHRONY IS MANUALLY ADJUSTING THE SYSTEM SETTING UP CHRONY FOR A SYSTEM IN AN ISOLATED configuring REMOTE MONITORING MANAGING TIME SYNCHRONIZATION USING RHEL SYSTEM ADDITIONAL RESOURCESCHAPTER 31. CHRONY WITH HW VERIFYING SUPPORT FOR HARDWARE ENABLING HARDWARE configuring CLIENT POLLING ENABLING INTERLEAVED configuring SERVER FOR LARGE NUMBER OF VERIFYING HARDWARE configuring PTP-NTP BRIDGECHAPTER 32. ACHIEVING SOME SETTINGS PREVIOUSLY SUPPORTED BY NTP IN MONITORING BY NTPQ AND USING AUTHENTICATION MECHANISM BASED ON PUBLIC KEY USING EPHEMERAL SYMMETRIC ASSOCIATIONS1441441471471491501521541551 5515515615715715815815816016016216216216 4164164165166167167167168169170171172173 173174174174175175176177177177178 Table of Contents5.