Book Image

CentOS 7 Linux Server Cookbook - Second Edition

By : Jonathan Hobson
Book Image

CentOS 7 Linux Server Cookbook - Second Edition

By: Jonathan Hobson

Overview of this book

This book will provide you with a comprehensive series of starting points that will give you direct access to the inner workings of the latest CentOS version 7 and help you trim the learning curve to master your server. You will begin with the installation and basic configuration of CentOS 7, followed by learning how to manage your system, services and software packages. You will then gain an understanding of how to administer the file system, secure access to your server and configure various resource sharing services such as file, printer and DHCP servers across your network. Further on, we cover advanced topics such as FTP services, building your own DNS server, running database servers, and providing mail and web services. Finally, you will get a deep understanding of SELinux and you will learn how to work with Docker operating-system virtualization and how to monitor your IT infrastructure with Nagios. By the end of this book, you will have a fair understanding of all the aspects of configuring, implementing and administering CentOS 7 Linux server and how to put it in control.

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CentOS 7 Linux Server Cookbook - Second Edition
Jonathan Hobson
Jan, 2016 | 326 pages
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Table of Contents (22 chapters)
CentOS 7 Linux Server Cookbook Second Edition
CentOS 7 Linux Server Cookbook Second Edition
Credits
Credits
About the Authors
About the Authors
About the Reviewer
About the Reviewer
www.PacktPub.com
www.PacktPub.com
Preface
Preface
Free Chapter
1
Installing CentOS
Installing CentOS
Introduction
Downloading CentOS and confirming the checksum on Windows or OS X
Creating USB installation media on Windows or OS X
Performing an installation of CentOS using the graphical installer
Running a netinstall over HTTP
Installing CentOS 7 using a kickstart file
Getting started and customising the boot loader
Troubleshooting the system in rescue mode
Updating the installation and enhancing the minimal install with additional administration and development tools
2
Configuring the System
Configuring the System
Introduction
Navigating text files with less
Introduction to Vim
Speaking the right language
Synchronizing the system clock with NTP and the chrony suite
Setting your hostname and resolving the network
Building a static network connection
Becoming a superuser
Customizing your system banners and messages
Priming the kernel
3
Managing the System
Managing the System
Introduction
Knowing and managing your background services
Troubleshooting background services
Tracking system resources with journald
Configuring journald to make it persistent
Managing users and their groups
Scheduling tasks with cron
Synchronizing files and doing more with rsync
Maintaining backups and taking snapshots
Monitoring important server infrastructure
Taking control with GIT and Subversion
4
Managing Packages with YUM
Managing Packages with YUM
Introduction
Using YUM to update the system
Using YUM to search for packages
Using YUM to install packages
Using YUM to remove packages
Keeping YUM clean and tidy
Knowing your priorities
Using a third-party repository
Creating a YUM repository
Working with the RPM package manager
5
Administering the Filesystem
Administering the Filesystem
Introduction
Creating a virtual block device
Formatting and mounting a filesystem
Using disk quotas
Maintaining a filesystem
Extending the capacity of the filesystem
6
Providing Security
Providing Security
Introduction
Locking down remote access and hardening SSH
Installing and configuring fail2ban
Working with a firewall
Forging the firewall rules by example
Generating self-signed certificates
Using secure alternatives to FTP
7
Building a Network
Building a Network
Introduction
Printing with CUPS
Running a DHCP server
Using WebDAV for file sharing
Installing and configuring NFS
Working with NFS
Securely sharing resources with Samba
8
Working with FTP
Working with FTP
Introduction
Installing and configuring the FTP service
Working with virtual FTP users
Customizing the FTP service
Troubleshooting users and file transfers
9
Working with Domains
Working with Domains
Introduction
Installing and configuring a caching-only nameserver
Setting up an authoritative-only DNS server
Creating an integrated nameserver solution
Populating the domain
Building a secondary (slave) DNS server
10
Working with Databases
Working with Databases
Introduction
Installing a MariaDB database server
Managing a MariaDB database
Allowing remote access to a MariaDB server
Installing a PostgreSQL server and managing a database
Configuring remote access to PostgreSQL
Installing phpMyAdmin and phpPgAdmin
11
Providing Mail Services
Providing Mail Services
Introduction
Configuring a domain-wide mail service with Postfix
Working with Postfix
Delivering the mail with Dovecot
Using Fetchmail
12
Providing Web Services
Providing Web Services
Introduction
Installing Apache and serving web pages
Enabling system users and building publishing directories
Implementing name-based hosting
Implementing CGI with Perl and Ruby
Installing, configuring, and testing PHP
Securing Apache
Setting up HTTPS with Secure Sockets Layer (SSL)
13
Operating System-Level Virtualization
Operating System-Level Virtualization
Introduction
Installing and configuring Docker
Downloading an image and running a container
Creating your own images from Dockerfiles and uploading to Docker Hub
Setting up and working with a private Docker registry
14
Working with SELinux
Working with SELinux
Introduction
Installing and configuring important SELinux tools
Working with SELinux security contexts
Working with policies
Troubleshooting SELinux
15
Monitoring IT Infrastructure
Monitoring IT Infrastructure
Introduction
Installing and configuring Nagios Core
Setting up NRPE on remote client hosts
Monitoring important remote system metrics
Index
Index

Managing users and their groups

In this recipe, we will learn how to manage your system's users and groups on CentOS 7. Essential user and group managing skills are one of the most important CentOS system administrator fundamentals.

Getting ready

To complete this recipe, you will need a working installation of the CentOS 7 operating system with root privileges and a console-based text editor of your choice.

How to do it...

This recipe shows you how to manage users and groups by learning how to add, delete, and modify them:

  1. To begin this recipe, we log in as root and type the following command to get a list of all the users known to the system: cat /etc/passwd.

  2. Now, show the root user ID (UID) and group ID (GID):

    id root

  3. Next, we will run the following command to add a new user to the system (exchange your_new_username with a username of your choice):

    useradd your_new_username

  4. However, in order to complete this process, you will be expected to provide a suitable password. To do this, type the following...

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