Red Hat System Administration II
Explain Kickstart concepts and architecture, create a Kickstart file with the Kickstart Generator website, modify an existing Kickstart file with a text editor and check its syntax with
ksvalidator, publish a Kickstart file to the installer, and install Kickstart on the network.
The Kickstart feature of Red Hat Enterprise Linux automates system installations. You can use Kickstart text files to configure disk partitioning, network interfaces, package selection, and customize the installation. The Anaconda installer uses Kickstart files for a complete installation without user interaction. The Kickstart feature is similar and uses an unattended installation answer file for Microsoft Windows.
Kickstart files begin with a list of commands that define how to install the target machine.
The installer ignores comment lines, which start with the number sign (#) character.
Additional sections each begin with a specific directive that starts with the percentage sign (%) character.
The %end directive marks the end of each section.
The %packages section specifies which software to include on installation. Specify individual packages by name, without versions. The at sign (@) character denotes package groups (either by group or ID), and the @^ characters denote environment groups (groups of package groups). Lastly, use the @module:stream/profile syntax to denote module streams.
Groups have mandatory, default, and optional components. Normally, Kickstart installs mandatory and default components. To exclude a package or a package group from the installation, precede it with a hyphen (-) character. Excluded packages or package groups might still install if they are mandatory dependencies of other requested packages.
A Kickstart configuration file typically includes one or more %pre and %post sections, which contain scripts that further configure the system. The %pre scripts execute before any disk partitioning is done. Typically, you use %pre scripts to initialize a storage or network device that the remainder of the installation requires. The %post scripts execute after the initial installation is complete. Scripts within the %pre and %post sections can use any available interpreter on the system, including Bash or Python. Avoid the use of a %pre section, because any errors that occur within it might be difficult to diagnose.
Lastly, you can specify as many sections as you need, in any order. For example, you can have two %post sections, and they are interpreted in order of appearance.
Note
The RHEL Image Builder is an alternative installation method to Kickstart files. Rather than a text file that provides installation instructions, Image Builder creates an image with all the required system changes. The RHEL Image Builder can create images for public clouds such as Amazon Web Services and Microsoft Azure, or for private clouds such as OpenStack or VMware. See this section's references for more information about the RHEL Image Builder.
The following Kickstart commands configure the installation source and method:
url: Specifies the URL that points to the installation media.url --url="http://classroom.example.com/content/rhel9.0/x86_64/dvd/"
repo: Specifies where to find additional packages for installation. This option must point to a validDNFrepository.repo --name="appstream" --baseurl=http://classroom.example.com/content/rhel9.0/x86_64/dvd/AppStream/
text: Forces a text mode installation.vnc: Enables the VNC viewer so you can access the graphical installation remotely over VNC.vnc --password=redhat
The following Kickstart commands configure devices and partitioning schemes:
clearpart: Removes partitions from the system before creating partitions.clearpart --all --drives=vda,vdb
part: Specifies the size, format, and name of a partition. Required unless theautopartormountcommands are present.part /home --fstype=ext4 --label=homes --size=4096 --maxsize=8192 --grow
autopart: Automatically creates a root partition, a swap partition, and an appropriate boot partition for the architecture. On large enough drives (50 GB+), this command also creates a/homepartition.ignoredisk: Prevents Anaconda from modifying disks, and is useful alongside theautopartcommand.ignoredisk --drives=sdc
bootloader: Defines where to install the bootloader. Required.bootloader --location=mbr --boot-drive=sda
volgroup,logvol: Creates LVM volume groups and logical volumes.part pv.01 --size=8192 volgroup myvg pv.01 logvol / --vgname=myvg --fstype=xfs --size=2048 --name=rootvol --grow logvol /var --vgname=myvg --fstype=xfs --size=4096 --name=varvol
zerombr: Initialize disks whose formatting is unrecognized.
The following Kickstart commands configure networking-related features:
network: Configures network information for the target system. Activates network devices in the installer environment.network --device=eth0 --bootproto=dhcp
firewall: Defines the firewall configuration for the target system.firewall --enabled --service=ssh,http
The following Kickstart commands configure security, language, and region settings:
lang: Sets the language to use on the installed system. Required.lang en_US
keyboard: Sets the system keyboard type. Required.keyboard --vckeymap=us
timezone: Defines the time zone and whether the hardware clock uses UTC. Required.timezone --utc Europe/Amsterdam
timesource: Enables or disables NTP. If you enable NTP, then you must specify NTP servers or pools.timesource --ntp-server classroom.example.com
authselect: Sets up authentication options. Options that theauthselectcommand recognizes are valid for this command. See authselect(8).rootpw: Defines the initialrootuser password. Required.rootpw --plaintext redhat
orrootpw --iscrypted $6$KUnFfrTzO8jv.PiH$YlBbOtXBkWzoMuRfb0.SpbQ....XDR1UuchoMG1selinux: Sets the SELinux mode for the installed system.selinux --enforcing
services: Modifies the default set of services to run under the defaultsystemdtarget.services --disabled=network,iptables,ip6tables --enabled=NetworkManager,firewalld
group,user: Creates a local group or user on the system.group --name=admins --gid=10001 user --name=jdoe --gecos="John Doe" --groups=admins
The following Kickstart commands configure logging the host power state on completion:
logging: This command defines how Anaconda handles logging during the installation.logging --host=loghost.example.com
firstboot: If enabled, then the Set up Agent starts the first time that the system boots. This command requires theinitial-setuppackage.firstboot --disabled
reboot,poweroff,halt: Specify the final action when the installation completes. The default setting is thehaltoption.
Note
Most Kickstart commands have multiple available options. Review the Kickstart Commands and Options guide in this section's references for more information.
In the following example, the first part of the Kickstart file consists of the installation commands, such as disk partitioning and installation source.
#version=RHEL9 # Define system bootloader options bootloader --append="console=ttyS0 console=ttyS0,115200n8 no_timer_check net.ifnames=0 crashkernel=auto" --location=mbr --timeout=1 --boot-drive=vda # Clear and partition disks clearpart --all --initlabel ignoredisk --only-use=vda zerombr part / --fstype="xfs" --ondisk=vda --size=10000 # Define installation options text repo --name="appstream" --baseurl="http://classroom.example.com/content/rhel9.0/x86_64/dvd/AppStream/" url --url="http://classroom.example.com/content/rhel9.0/x86_64/dvd/" # Configure keyboard and language settings keyboard --vckeymap=us lang en_US # Set a root password, authselect profile, and selinux policy rootpw --plaintext redhat authselect select sssd selinux --enforcing firstboot --disable # Enable and disable system services services --disabled="kdump,rhsmcertd" --enabled="sshd,rngd,chronyd" # Configure the system timezone and NTP server timezone America/New_York --utc timesource --ntp-server classroom.example.com
The second part of a Kickstart file contains the %packages section, with details of which packages and package groups to install, and which packages not to install.
%packages @core chrony cloud-init dracut-config-generic dracut-norescue firewalld grub2 kernel rsync tar -plymouth %end
The last part of the Kickstart file contains a %post installation script.
%post echo "This system was deployed using Kickstart on $(date)" > /etc/motd %end
You can also specify a Python script with the --interpreter option.
%post --interpreter="/usr/libexec/platform-python"
print("This line of text is printed with python")
%endNote
In a Kickstart file, missing required values cause the installer to interactively prompt for an answer or to abort the installation entirely.
Use the following steps to automate the installation of Red Hat Enterprise Linux with the Kickstart feature:
Create a Kickstart file.
Publish the Kickstart file so that the Anaconda installer can access it.
Boot the Anaconda installer and point it to the Kickstart file.
You can use either of these methods to create a Kickstart file:
Use the Kickstart Generator website.
Use a text editor.
The Kickstart Generator site at https://access.redhat.com/labs/kickstartconfig presents dialog boxes for user inputs, and creates a Kickstart configuration file with the user's choices. Each dialog box corresponds to the configurable items in the Anaconda installer.
Creating a Kickstart file from scratch is complex, so first try to edit an existing file. Every installation creates a /root/anaconda-ks.cfg file that contains the Kickstart directives that are used in the installation. This file is a good starting point to create a Kickstart file.
The ksvalidator utility checks for syntax errors in a Kickstart file. It ensures that keywords and options are correctly used, but it does not validate URL paths, individual packages, groups, nor any part of %post or %pre scripts. For example, if the firewall --disabled directive is misspelled, then the ksvalidator command might produce one of the following errors:
[user@host ~]$ksvalidator /tmp/anaconda-ks.cfgThe following problem occurred on line 10 of the kickstart file: Unknown command: frewall [user@host ~]$ksvalidator /tmp/anaconda-ks.cfgThe following problem occurred on line 10 of the kickstart file: no such option: --dsabled
The ksverdiff utility displays syntax differences between different operating system versions. For example, the following command displays the Kickstart syntax changes between RHEL 8 and RHEL 9:
[user@host ~]$ ksverdiff -f RHEL8 -t RHEL9
The following commands were removed in RHEL9:
device deviceprobe dmraid install multipath
The following commands were deprecated in RHEL9:
autostep btrfs method
The following commands were added in RHEL9:
timesource
...output omitted...The pykickstart package provides the ksvalidator and ksverdiff utilities.
Provide the Kickstart file to the installer by placing it in one of these locations:
A network server that is available at installation time by using FTP, HTTP, or NFS.
An available USB disk or CD-ROM.
A local hard disk on the system.
The installer must access the Kickstart file to begin an automated installation. Usually, the file is made available via an FTP, web, or NFS server. Network servers help with Kickstart file maintenance, because changes can be made once, and then immediately be used for future installations.
By providing Kickstart files on USB or CD-ROM, is also convenient. The Kickstart file can be embedded in the boot media that starts the installation. However, when the Kickstart file is changed, you must generate new installation media.
Providing the Kickstart file on a local disk enables a quick rebuild of a system.
After a Kickstart method is chosen, the installer is told where to locate the Kickstart file by passing the inst.ks= parameter to the installation kernel.LOCATION
Consider the following examples:
inst.ks=http://server/dir/fileinst.ks=ftp://server/dir/fileinst.ks=nfs:server:/dir/fileinst.ks=hd:device:/dir/fileinst.ks=cdrom:device
For virtual machine installations by using the or virt-manager, the Kickstart URL can be specified in a box under . When installing physical machines, boot by using installation media, and press the Tab key to interrupt the boot process. Add an inst.ks= parameter to the installation kernel.LOCATION
References
For further information, refer to Kickstart Installation Basics chapter in Performing an Advanced RHEL Installation at https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html-single/performing_an_advanced_rhel_9_installation/index#performing_an_automated_installation_using_kickstart
For further information, refer to Kickstart Commands and Options Reference in Performing an Advanced RHEL Installation at https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html-single/performing_an_advanced_rhel_9_installation/index#kickstart-commands-and-options-reference_installing-rhel-as-an-experienced-user
For further information, refer to Composing a Customized RHEL System Image at https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html-single/composing_a_customized_rhel_system_image/index
