Pattern - Kickstart Image Creation
RedHat Kickstart can be used to create machine images which real or virtual linux servers boot off.
Features
- A kickstart boot image (floppy, ISO CD/DVD or PXE preboot) is created that boots the machine
- This image includes a configuration file that lists
- drivers to load at boot time
- a list of pre-install operations, including how to partition/format the hard disk, which bootloader to install, and whether the disk should upgrade or install the OS
- a list of RPMs to install
- a URL to the filesystem (including HTTP) containing the RPMs
- a list of post-install operations to perform
Advantages
- Small boot images can be used to bring up machines into chosen configurations.
- Different configurations can be served off the same RPM repository; it is the configuration file that chooses which packages to install.
- Servers can be local or remote
- The cost of installing a cluster of (identical) machines is reduced to that of creating the configuration file itself, and of hosting the remote RPM server.
- A full clean install guarantees that the target machines are clean and ready for use.
- Works well with Virtual Machine images, where PXE preboot or an ISO image mounted on a virtual CD-ROM drive can be used to start the installation.
Disadvantages
- Passwords can be sent in the clear.
- PGP keys of RPMs to trust are downloaded off the remote repository, hence essentially worthless as a security measure.
- The load of 1000 servers trying to boot a kickstart image simultaneously can be severe.
- Adding/updating an RPM is more complex than just adding the file, one needs to run genhdlist to rebuild the indices.
- To change a machine's role, it may need to be rebooted against a different kickstart image.
- Building a new image can still be time-consuming.
SmartFrog support
There is no formal support in SmartFrog for creating kickstart configuration files or images, or for hosting an HTTP-based RPM server, though these features can be glued together by hand.
SmartFrog is available as an RPM distribution; this RPM can be served up over kickstart, creating machines which can be configured post-installation into different roles.
LinuxCOE Support
The HP-backed SourceForge-hosted project LinuxCOE can be used to set up a private Kickstart server, with a web-based GUI to create new machine images. This makes it very easy and cheap to build a new image off the same central filestore.
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