A Beginner‘s Guide to Kickstarting Linux

Kickstart is a powerful tool that allows you to automate the installation and configuration of Linux operating systems like RHEL, CentOS, and Fedora. With kickstart, you can install Linux on multiple machines without user interaction, making it perfect for deployments across large server farms or computer labs.

In this comprehensive guide for beginners, I‘ll cover everything you need to know to get started with kickstart including:

• What is kickstart and how it works
• The benefits of automating Linux installs
• How to create a kickstart file
• kickstart command syntax and file structure
• Configuring a kickstart server and making files accessible
• Booting systems into a kickstart install
• Tips for troubleshooting kickstart issues

So if you‘re looking to streamline your Linux deployments through automation, read on!

What is Kickstart?

Kickstart is an automated installation method for quickly deploying the Linux operating system on multiple computers. It works by using a kickstart file – a simple text file containing answers to all questions normally asked during a manual OS installation.

The kickstart file provides the installation wizard with predefined configurations for disk partitioning, network setup, authentication credentials, package selection and more. When supplied early in the boot process, this automated install file allows Linux to be deployed without any user interaction needed.

Red Hat developed kickstart to facilitate rapid mass-deployment of their Linux distributions (RHEL, CentOS, Fedora etc). The kickstart configuration syntax is implemented in Red Hat’s graphical and text-based installation wizards – Anaconda and VNC.

Benefits of Kickstart Automation

Kickstart offers large productivity gains for Linux system administrators managing more than just a few servers:

Rapid Unattended Installation: After initial file creation, operating systems can be deployed without admin involvement – freeing up valuable time.

Consistency & Compliance: Configurations based on approved corporate standards can be applied reliably across Linux estates.

Scalability: Going from 10 servers to 1000 is easy, just boot additional systems using the same kickstart file.

Flexibility: Installations can be tailored to match hardware configs and organizational requirements.

Remote Management: New Linux systems can be rapidly brought online at remote datacenter facilities.

Hands-free Operation: No need for an admin to babysit installs or answer configuration questions.

Now that you understand the basics of kickstart and its key benefits, let’s look at how to create a kickstart file…

Creating a Kickstart File

While kickstart files can be written from scratch in a text editor, it’s easier for beginners to use the config file auto-generated during a manual OS install.

Follow this simple process:

1. Manually install RHEL/CentOS as normal through Anaconda but don’t reboot yet.

2. Find the automatically created kickstart file /root/anaconda-ks.cfg

3. Copy this file to edit and use for unattended deployments.

The anaconda-ks.cfg grab all your selections – disk layout, network config, software choices etc. It can serve as a perfect starter kickstart file for cloned systems with similar hardware or use cases.

Let’s explore some key sections…

Kickstart File Structure

A kickstart file contains sections that match the install wizard screens e.g:

#platform config 
#language selection
#keyboard layout 
#disk partitioning 
#network setup
#authentication  
#firewall rules
#package selection
#bootloader options

Many sections are optional and kickstart will take defaults if omitted. However some sections like disk partitioning are vital for automated installation success.

Lines starting with % or # are comments to document sections. These help when modifying or troubleshooting complex files.

#The following section configures disk partitioning
%partition

Now for the most important bit – kickstart commands…

Kickstart Command Syntax

Each install wizard screen has associated kickstart commands allowing full configuration without user input. Here are some commonly used examples:

#Language  
lang en_US

#Keyboard
keyboard us 

#Root password
rootpw --iscrypted $1$sSVCTUp$7kc/TS9GTLrsYuOIR8

#Partition clearing 
clearpart --all 

#Disk partitioning
part /boot --fstype ext4 --size=512  
part pv.01 --grow --size=1
volgroup vg00 pv.01
logvol / --fstype xfs --name=lv_root --vgname=vg00 --grow --size=1

#Network with static IP 
network --bootproto=static --ip=192.168.0.100 --netmask=255.255.224.0 --gateway=192.168.0.1 --hostname=node001

#Disable firewall
firewall --disabled 

#Enable SELinux
selinux --enforcing

These show the general structure of kickstart commands:

commandname [options]

where options customize each setting as required.

Let’s look at using kickstart files…

Configuring a Kickstart Server

To use kickstart for unattended deployments we need to:

1. Create a kickstart file with all our selections

2. Make this file accessible to new systems during boot

There are several ways to achieve step 2:

• Upload file to a web server

• Share via NFS, FTP or HTTP server

• Place directly on installation media with OS .iso

• Create PXE boot infrastructure to serve file

The simplest approach is hosting the KS file on an HTTP server along with the OS media:

Web server config:

[KICKSTART]    
192.168.0.2/centos7   <directory holding KS file + OS .iso>

New systems would boot the OS media then pull the KS file from our web server share.

Let‘s look at starting a kickstart deployment…

Booting Systems into a Kickstart Installation

With the kickstart file available remotely and OS media mounted we can now boot systems so the automatic installation begins.

Use one of the following approaches:

1. PXE Boot

Configure PXE boot server to load installation kernel+initrd and supply kickstart file URL:

append initrd=initrd.img ks=http://192.168.0.2/ks.cfg

New machines will PXE boot then retrieve complete unattended OS deploy using our kickstart file.

2. Boot Media Parameters

Burn CD/DVD/USB media with OS .iso + kickstart file added.

At media boot screen, edit parameters to load KS file:

linux ks=cdrom:/ks.cfg

This performs automated install using kickstart directly off the boot media.

3. DHCP Server (bootp)

Some DHCP servers allow filename boot parameters to be configured:

filename "linux ks=http://192.168.0.2/ks.cfg”

Clients get sent to kickstart URL automatically on bootup.

4. Boot Loader Config

For hard disk installs with existing GRUB setup, edit grub.cfg:

linuxefi ks=hd:/dev/sda1:/ks.cfg

This specifies location of kickstart file on a partition.

Now that you know the different methods to launch kickstart, let’s talk troubleshooting…

Troubleshooting Kickstart Issues

If issues arise during automated deployment, first check boot parameters used correctly specify location of the KS file.

Next inspect logs in /tmp including kickstart log files which end *.log. These logs record the entire install process including all errors encountered so are invaluable for deciphering any failures.

Some common problems:

Disk partition issues: Look for errors around disk layout as improperly specified partitions will fail deployment.

Missing packages: Kickstart file doesn‘t include required RPM packages resulting in an incomplete build.

Network problems: Check DHCP or static IP setup failed stopping installation Completing.

Service failures: Look for services unable to start due to missing packages or libraries.

Boot issues: GRUB or other bootloader may fail to install blocking system boot.

Careful log analysis coupled with selectively adding %post scripts can help identify and resolve virtually any issues with automated kickstart deployment.

Conclusion

I hope this guide has provided a helpful kickstart overview and good foundation for beginners looking to streamline Linux deployments at scale.

The key concepts we’ve covered:

• Kickstart principles and how automation benefits system administrators

• Creating a kickstart file from base OS install

• Kickstart syntax and commands to customize deployments

• Making kickstart files accessible via HTTP and PXE boot

• Options to launch an automated installation

• Debugging common issues with logging

Just remember – an effective kickstart implementation takes time to perfect across your hardware and use cases. Start simple then build on what works.

Fully leveraging kickstart automation will let you scale Linux rollouts from 10s to 1000s easily, while drastically reducing operational overheads!