Red Hat Enterprise Linux 9 Administration

Cover
Title Page
Copyright and credits
Contributors
Table of Contents
Preface
Part 1 – Systems Administration – Software, User, Network, and Services Management
Chapter 1: Getting RHEL Up and Running
	Technical requirements
	Obtaining RHEL and a subscription
	Installing RHEL 9
		Preparation for a physical server installation
		Preparation for a virtual server installation
		Running an RHEL installation
	Summary
Chapter 2: RHEL 9 Advanced Installation Options
	Technical requirements
	Automating RHEL deployments with Anaconda
	Deploying RHEL on the cloud
	Installation best practices
	Summary
Chapter 3: Basic Commands and Simple Shell Scripts
	Logging in as a user and managing multi-user environments
		Using the root account
		Using and understanding the command prompt
	Changing users with the su command
	Understanding users, groups, and basic permissions
		Users
		Groups
		File permissions
	Using the command line, environment variables, and navigating through the filesystem
		Command line and environment variables
		Navigating the filesystem
		Bash auto-complete
		The filesystem hierarchy
	Understanding I/O redirection on the command line
	Filtering output with grep and sed
	Listing, creating, copying, and moving files, directories, links, and hard links
		Directories
		Copying and moving
		Symbolic and hard links
	Using tar and gzip
	Creating basic shell scripts
		for loops
		if conditionals
		Exit codes
	Using system documentation resources
		man pages
		info pages
		Other documentation resources
	Summary
Chapter 4: Tools for Regular Operations
	Technical requirements
	Managing system services with systemd
		systemd unit file structure
		Managing services to be started and stopped at boot
		Managing boot targets
	Scheduling tasks with cron and systemd
		System-wide crontab
		User crontab
		systemd timers
	Learning about time synchronization with chrony and NTP
		NTP client
		NTP server
	Checking for free resources – memory and disk (free and df)
		Memory
		Disk space
		CPU
		Load average
		Other monitoring tools
	Finding logs, using journald, and reading log files, including log preservation and rotation
		Log rotation
	Summary
Chapter 5: Securing Systems with Users, Groups, and Permissions
	Creating, modifying, and deleting local user accounts and groups
	Managing groups and reviewing assignments
	Adjusting password policies
	Configuring sudo access for administrative tasks
		Understanding sudo configuration
		Using sudo to run admin commands
		Configuring sudoers
	Checking, reviewing, and modifying file permissions
	Using special permissions
		Understanding and applying SUID
		Understanding and applying SGID
		Using the sticky bit
	Summary
Chapter 6: Enabling Network Connectivity
	Technical requirements
	Exploring network configuration in RHEL
	Getting to know the configuration files and NetworkManager
	Configuring network interfaces with IPv4 and IPv6
		IPv4 and IPv6 – what do they mean?
		Configuring interfaces with nmtui
		Configuring interfaces with nm-connection-editor
		Configuring interfaces with nmcli
		Where does NetworkManager store configuration?
	Configuring hostname and hostname resolutions (DNS)
	An overview of firewall configuration
		Configuring the firewall
	Testing network connectivity
	Summary
Chapter 7: Adding, Patching, and Managing Software
	RHEL subscription registration and management
	Managing repositories and signatures with yum/dnf
	Doing software installations, updates, and rollbacks with YUM/DNF
	Creating and syncing repositories with createrepo and reposync
	Understanding RPM internals
	Summary
Part 2 – Security with SSH, SELinux, a Firewall, and System Permissions
Chapter 8: Administering Systems Remotely
	Technical requirements
	SSH and OpenSSH overview and base configuration
		OpenSSH server
		OpenSSH client
	Enabling root access via SSH (and when not to do it)
	Accessing remote systems with SSH
	Key-based authentication with SSH
		SSH agent
	Remote file management with SCP/rsync
		Transferring files with an OpenSSH secure file copy
		Transferring files with sftp
		Transferring files with rsync
	Advanced remote management – SSH tunnels and SSH redirections
	Remote terminals with tmux
	Introduction to Ansible automation
		Inventory
		Playbook
	Summary
Chapter 9: Securing Network Connectivity with firewalld
	Introduction to the RHEL firewall – firewalld
	Enabling firewalld in the system and reviewing the default zones
		Reviewing the different configuration items under firewalld
	Enabling and managing services and ports
	Creating and using service definitions for firewalld
	Configuring firewalld with the web interface
	Summary
Chapter 10: Keeping Your System Hardened with SELinux
	Technical requirements
	SELinux usage in enforcing and permissive modes
	Reviewing the SELinux context for files and processes
	Tweaking the policy with semanage
	Restoring changed file contexts to the default policy
	Using SELinux Boolean settings to enable services
	SELinux troubleshooting and common fixes
	Integrity Measurement Architecture, digital hashes, and signatures for enhancing security
		EVM and trusted keys
		Enabling IMA and EVM in the system kernel
	Summary
Chapter 11: System Security Profiles with OpenSCAP
	Getting started with OpenSCAP and discovering system vulnerabilities
	Using OpenSCAP with security profiles for OSPP and PCI DSS
		Scanning for OSPP compliance
		Scanning for PCI DSS compliance
	Summary
Part 3 – Resource Administration – Storage, Boot Process, Tuning, and Containers
Chapter 12: Managing Local Storage and Filesystems
	Technical requirements
		Let’s start with a definition
		A bit of history
	Partitioning disks (MBR and GPT disks)
	Formatting and mounting filesystems
	Setting default mounts and options in fstab
	Using network filesystems with NFS
	Summary
Chapter 13: Flexible Storage Management with LVM
	Technical requirements
	Understanding LVM
	Creating, moving, and removing physical volumes
	Combining physical volumes into volume groups
	Creating and extending logical volumes
	Adding new disks to a volume group and extending an logical volume
	Removing logical volumes, volume groups, and physical volumes
	Reviewing LVM commands
	Summary
Chapter 14: Advanced Storage Management with Stratis and VDO
	Technical requirements
	Understanding Stratis
	Installing and enabling Stratis
	Managing storage pools and filesystems with Stratis
	Preparing systems to use VDO
	Creating and using a VDO volume
	Testing a VDO volume and reviewing the stats
	Summary
Chapter 15: Understanding the Boot Process
	Understanding the boot process – BIOS and UEFI booting
	Working with GRUB, the bootloader, and the initrd system images
	Managing the boot sequence with systemd
	Intervening in the boot process to gain access to a system
	Summary
Chapter 16: Kernel Tuning and Managing Performance Profiles with tuned
	Technical requirements
	Identifying processes, checking memory usage, and killing processes
	Adjusting kernel scheduling parameters to better manage processes
	Installing tuned and managing tuning profiles
	Creating a custom tuned profile
	Using the web console for observing performance metrics
	Summary
Chapter 17: Managing Containers with Podman, Buildah, and Skopeo
	Technical requirements
	Introduction to containers
		Installing container tools
	Running a container using Podman and UBI
		Basic container management – pull, run, stop, and remove
		Attaching persistent storage to a container
		Deploying a container on a production system with systemd
		Building a container image using a Dockerfile or Containerfile
		Configuring Podman to search registry servers
		Summary of Podman options
	When to use Buildah and Skopeo
		Building container images with Buildah
		Inspecting a remote container with Skopeo
	Summary
Part 4 – Practical Exercises
Chapter 18: Practice Exercises – 1
	Technical requirements
	Tips for the exercise
	Practice exercise 1
	Exercise 1 solution
Chapter 19: Practice Exercise – 2
	Technical requirements
	Tips for the exercise
	Practice exercise 2
	Exercise 2 resolution
Index
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