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Red Hat Enterprise Linux 8 Essentials

By : Neil Smyth
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Book Image

Red Hat Enterprise Linux 8 Essentials

1 (1)
By: Neil Smyth

Overview of this book

Red Hat Enterprise Linux 8 is one of the most secure and dependable operating systems available. For this reason, the ambitious system or network engineer will find a working knowledge of Red Hat Enterprise 8 to be an invaluable advantage in their respective fields. This book, now updated for RHEL 8.1, begins with a history of Red Enterprise Linux and its installation. You will be virtually perform remote system administration tasks with cockpit web interface and write shell scripts to maintain server-based systems without desktop installation. Then, you will set up a firewall system using a secure shell and enable remote access to Gnome desktop environment with virtual network computing (VNC). You’ll share files between the Red Hat Enterprise Linux 8 (RHEL 8) and Windows System using Samba client and NFS. You will also run multiple guest operating systems using virtualization and Linux containers, and host websites using RHEL 8 by installing an Apache web server. Finally, you will create logical disks using logical volume management and implement swap space to maintain the performance of a RHEL 8 system. By the end of this book, you will be armed with the skills and knowledge to install the RHEL 8 operating system and use it expertly.

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Red Hat Enterprise Linux 8 Essentials
Neil Smyth
Jun, 2019 | 266 pages
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Table of Contents (32 chapters)
Free Chapter
1
1. Introduction
1. Introduction
1.1 Superuser Conventions
1.2 Feedback
1.3 Errata
2
2. A Brief History of Red Hat Linux
2. A Brief History of Red Hat Linux
2.1 What exactly is Linux?
2.2 UNIX Origins
2.3 Who Created Linux?
2.4 The Early Days of Red Hat
2.5 Red Hat Support
2.6 Open Source
2.7 The Fedora Project
2.8 CentOS - The Free Alternative
2.9 Summary
3
3. Installing RHEL 8 on a Clean Disk Drive
3. Installing RHEL 8 on a Clean Disk Drive
3.1 Obtaining the Red Hat Enterprise Linux Installation Media
3.2 Writing the ISO Installation Image to a USB Drive
3.3 Installing Red Hat Enterprise Linux 8
3.4 Partitioning a Disk for RHEL 8
3.5 The Physical Installation
3.6 Final Configuration Steps
3.7 Installing Updates
3.8 Displaying Boot Messages
3.9 Summary
4
4. Dual Booting RHEL 8 with Windows
4. Dual Booting RHEL 8 with Windows
4.1 Partition Resizing
4.2 Editing the RHEL 8 Boot Menu
4.3 Changing the Default Boot Option
4.4 Accessing the Windows Partition from RHEL 8
4.5 Summary
5
5. Allocating Windows Disk Partitions to RHEL 8
5. Allocating Windows Disk Partitions to RHEL 8
5.1 Unmounting the Windows Partition
5.2 Deleting the Windows Partitions from the Disk
5.3 Formatting the Unallocated Disk Partition
5.4 Mounting the New Partition
5.5 Editing the Boot Menu
5.6 Summary
6
6. A Guided Tour of the GNOME 3 Desktop
6. A Guided Tour of the GNOME 3 Desktop
6.1 Installing the GNOME Desktop
6.2 An Overview of the GNOME 3 Desktop
6.3 Launching Activities
6.4 Managing Windows
6.5 Using Workspaces
6.6 Calendar and Notifications
6.7 Desktop Settings
6.8 Summary
7
7. An Overview of the RHEL 8 Cockpit Web Interface
7. An Overview of the RHEL 8 Cockpit Web Interface
7.1 An Overview of Cockpit
7.2 Installing and Enabling Cockpit
7.3 Accessing Cockpit
7.4 System
7.5 Logs
7.6 Storage
7.7 Networking
7.8 Podman Containers
7.9 Virtual Machines
7.10 Accounts
7.11 Services
7.12 Applications
7.13 Diagnostic Reports
7.14 Kernel Dump
7.15 SELinux
7.16 Software Updates
7.17 Subscriptions
7.18 Terminal
7.19 Connecting to Multiple Servers
7.20 Enabling Stored Metrics
7.21 Summary
8
8. Using the Bash Shell on RHEL 8
8. Using the Bash Shell on RHEL 8
8.1 What is a Shell?
8.2 Gaining Access to the Shell
8.3 Entering Commands at the Prompt
8.4 Getting Information about a Command
8.5 Bash Command-line Editing
8.6 Working with the Shell History
8.7 Filename Shorthand
8.8 Filename and Path Completion
8.9 Input and Output Redirection
8.10 Working with Pipes in the Bash Shell
8.11 Configuring Aliases
8.12 Environment Variables
8.13 Writing Shell Scripts
8.14 Summary
9
9. Managing RHEL 8 Users and Groups
9. Managing RHEL 8 Users and Groups
9.1 User Management from the Command-line
9.2 User Management with Cockpit
9.3 Summary
10
10. Understanding RHEL 8 Software Installation and Management
10. Understanding RHEL 8 Software Installation and Management
10.1 Repositories
10.2 The BaseOS Repository
10.3 The AppStream Repository
10.4 Summary
11
11. Configuring RHEL 8 systemd Units
11. Configuring RHEL 8 systemd Units
11.1 Understanding RHEL 8 systemd Targets
11.2 Understanding RHEL 8 systemd Services
11.3 RHEL 8 systemd Target Descriptions
11.4 Identifying and Configuring the Default Target
11.5 Understanding systemd Units and Unit Types
11.6 Dynamically Changing the Current Target
11.7 Enabling, Disabling and Masking systemd Units
11.8 Working with systemd Units in Cockpit
11.9 Summary
12
12. RHEL 8 Network Management
12. RHEL 8 Network Management
12.1 An Introduction to NetworkManager
12.2 Installing and Enabling NetworkManager
12.3 Basic nmcli Commands
12.4 Working with Connection Profiles
12.5 Interactive Editing
12.6 Configuring NetworkManager Permissions
12.7 Summary
13
13. Basic RHEL 8 Firewall Configuration with firewalld
13. Basic RHEL 8 Firewall Configuration with firewalld
13.1 An Introduction to firewalld
13.2 Checking firewalld Status
13.3 Configuring Firewall Rules with firewall-cmd
13.4 Managing firewalld from the Cockpit Interface
13.5 Managing firewalld using firewall-config
13.6 Summary
14
14. Configuring SSH Key-based Authentication on RHEL 8
14. Configuring SSH Key-based Authentication on RHEL 8
14.1 An Overview of Secure Shell (SSH)
14.2 SSH Key-based Authentication
14.3 Setting Up Key-based Authentication
14.4 SSH Key-based Authentication from Linux and macOS Clients
14.5 Managing Multiple Keys
14.6 SSH Key-based Authentication from Windows 10 Clients
14.7 SSH Key-based Authentication using PuTTY
14.8 Generating a Private Key with PuTTYgen
14.9 Installing the Public Key for a Google Cloud Instance
14.10 Summary
15
15. RHEL 8 Remote Desktop Access with VNC
15. RHEL 8 Remote Desktop Access with VNC
15.1 Secure and Insecure Remote Desktop Access
15.2 Installing the GNOME Desktop Environment
15.3 Installing VNC on RHEL 8
15.4 Configuring the VNC Server
15.5 Connecting to a VNC Server
15.6 Establishing a Secure Remote Desktop Session
15.7 Establishing a Secure Tunnel on Windows using PuTTY
15.8 Shutting Down a Desktop Session
15.9 Troubleshooting a VNC Connection
15.10 Summary
16
16. Displaying RHEL 8 Applications Remotely (X11 Forwarding)
16. Displaying RHEL 8 Applications Remotely (X11 Forwarding)
16.1 Requirements for Remotely Displaying RHEL 8 Applications
16.2 Remotely Displaying a RHEL 8 Application
16.3 Trusted X11 Forwarding
16.4 Compressed X11 Forwarding
16.5 Displaying Remote RHEL 8 Apps on Windows
16.6 Summary
17
17. Using NFS to Share RHEL 8 Files with Remote Systems
17. Using NFS to Share RHEL 8 Files with Remote Systems
17.1 Ensuring NFS Services are running on RHEL 8
17.2 Configuring the RHEL 8 Firewall to Allow NFS Traffic
17.3 Specifying the Folders to be Shared
17.4 Accessing Shared RHEL 8 Folders
17.5 Mounting an NFS Filesystem on System Startup
17.6 Unmounting an NFS Mount Point
17.7 Accessing NFS Filesystems in Cockpit
17.8 Summary
18
18. Sharing Files between RHEL 8 and Windows Systems with Samba
18. Sharing Files between RHEL 8 and Windows Systems with Samba
18.1 Samba and Samba Client
18.2 Installing Samba on a RHEL 8 System
18.3 Configuring the RHEL 8 Firewall to Enable Samba
18.4 Configuring the smb.conf File
18.5 Configuring SELinux for Samba
18.6 Creating a Samba User
18.7 Testing the smb.conf File
18.8 Starting the Samba and NetBIOS Name Services
18.9 Accessing Samba Shares
18.10 Accessing Windows Shares from RHEL 8
18.11 Summary
19
19. An Overview of Virtualization Techniques
19. An Overview of Virtualization Techniques
19.1 Guest Operating System Virtualization
19.2 Hypervisor Virtualization
19.3 Virtual Machine Networking
19.4 Summary
20
20. Installing KVM Virtualization on RHEL 8
20. Installing KVM Virtualization on RHEL 8
20.1 An Overview of KVM
20.2 KVM Hardware Requirements
20.3 Preparing RHEL 8 for KVM Virtualization
20.4 Verifying the KVM Installation
20.5 Summary
21
21. Creating KVM Virtual Machines using Cockpit and virt-manager
21. Creating KVM Virtual Machines using Cockpit and virt-manager
21.1 Installing the Cockpit Virtual Machines Module
21.2 Creating a Virtual Machine in Cockpit
21.3 Starting the Installation
21.4 Working with Storage Volumes and Storage Pools
21.5 Creating a Virtual Machine using virt-manager
21.6 Starting the Virtual Machine Manager
21.7 Configuring the KVM Virtual System
21.8 Starting the KVM Virtual Machine
21.9 Summary
22
22. Creating KVM Virtual Machines with virt-install and virsh
22. Creating KVM Virtual Machines with virt-install and virsh
22.1 Running virt-install to build a KVM Guest System
22.2 An Example RHEL 8 virt-install Command
22.3 Starting and Stopping a Virtual Machine from the Command-Line
22.4 Creating a Virtual Machine from a Configuration File
22.5 Summary
23
23. Creating a RHEL 8 KVM Networked Bridge Interface
23. Creating a RHEL 8 KVM Networked Bridge Interface
23.1 Getting the Current Network Settings
23.2 Creating a Network Bridge from the Command-Line
23.3 Declaring the KVM Bridged Network
23.4 Using a Bridge Network in a Virtual Machine
23.5 Creating a Bridge Network using nm-connection-editor
23.6 Summary
24
24. Managing KVM using the virsh Command-Line Tool
24. Managing KVM using the virsh Command-Line Tool
24.1 The virsh Shell and Command-Line
24.2 Listing Guest System Status
24.3 Starting a Guest System
24.4 Shutting Down a Guest System
24.5 Suspending and Resuming a Guest System
24.6 Saving and Restoring Guest Systems
24.7 Rebooting a Guest System
24.8 Configuring the Memory Assigned to a Guest OS
24.9 Summary
25
25. An Introduction to Linux Containers
25. An Introduction to Linux Containers
25.1 Linux Containers and Kernel Sharing
25.2 Container Uses and Advantages
25.3 RHEL 8 Container Tools
25.4 Container Catalogs, Repositories and Registries
25.5 Container Networking
25.6 Summary
26
26. Working with Containers on RHEL 8
26. Working with Containers on RHEL 8
26.1 Installing the Container Tools
26.2 Logging in to the Red Hat Container Registry
26.3 Pulling a Container Image
26.4 Running the Image in a Container
26.5 Managing a Container
26.6 Saving a Container to an Image
26.7 Removing an Image from Local Storage
26.8 Removing Containers
26.9 Building a Container with Buildah
26.10 Building a Container from Scratch
26.11 Container Bridge Networking
26.12 Managing Containers in Cockpit
26.13 Summary
27
27. Setting Up a RHEL 8 Web Server
27. Setting Up a RHEL 8 Web Server
27.1 Requirements for Configuring a RHEL 8 Web Server
27.2 Installing the Apache Web Server Packages
27.3 Configuring the Firewall
27.4 Port Forwarding
27.5 Starting the Apache Web Server
27.6 Testing the Web Server
27.7 Configuring the Apache Web Server for Your Domain
27.8 The Basics of a Secure Web Site
27.9 Configuring Apache for HTTPS
27.10 Obtaining an SSL Certificate
27.11 Summary
28
28. Configuring a RHEL 8 Postfix Email Server
28. Configuring a RHEL 8 Postfix Email Server
28.1 The structure of the Email System
28.2 Configuring a RHEL 8 Email Server
28.3 Postfix Pre-Installation Steps
28.4 Firewall/Router Configuration
28.5 Installing Postfix on RHEL 8
28.6 Configuring Postfix
28.7 Configuring DNS MX Records
28.8 Starting Postfix on a RHEL 8 System
28.9 Testing Postfix
28.10 Sending Mail via an SMTP Relay Server
28.11 Summary
29
29. Adding a New Disk Drive to a RHEL 8 System
29. Adding a New Disk Drive to a RHEL 8 System
29.1 Mounted File Systems or Logical Volumes
29.2 Finding the New Hard Drive
29.3 Creating Linux Partitions
29.4 Creating a File System on a RHEL 8 Disk Partition
29.5 An Overview of Journaled File Systems
29.6 Mounting a File System
29.7 Configuring RHEL 8 to Automatically Mount a File System
29.8 Adding a Disk Using Cockpit
29.9 Summary
30
30. Adding a New Disk to a RHEL 8 Volume Group and Logical Volume
30. Adding a New Disk to a RHEL 8 Volume Group and Logical Volume
30.1 An Overview of Logical Volume Management (LVM)
30.2 Getting Information about Logical Volumes
30.3 Adding Additional Space to a Volume Group from the Command-Line
30.4 Adding Additional Space to a Volume Group using Cockpit
30.5 Summary
31
31. Adding and Managing RHEL 8 Swap Space
31. Adding and Managing RHEL 8 Swap Space
31.1 What is Swap Space?
31.2 Recommended Swap Space for RHEL 8
31.3 Identifying Current Swap Space Usage
31.4 Adding a Swap File to a RHEL 8 System
31.5 Adding Swap as a Partition
31.6 Adding Space to a RHEL 8 LVM Swap Volume
31.7 Adding Swap Space to the Volume Group
31.8 Summary
32
Index
Index

11.1 Understanding RHEL 8 systemd Targets

RHEL 8 can be configured to boot into one of a number of states (referred to as targets), each of which is designed to provide a specific level of operating system functionality. The target to which a system will boot by default is configured by the system administrator based on the purpose for which the system is being used. A desktop system, for example, will most likely be configured to boot using the graphical user interface target, while a cloud-based server system would be more likely to boot to the multi-user target level.

During the boot sequence, a process named systemd looks in the /etc/systemd/system folder to find the default target setting. Having identified the default target, it proceeds to start the systemd units associated with that target so that the system boots with all the necessary processes running.

For those familiar with previous RHEL versions, systemd targets are the replacement for the older runlevel system...

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