Glossary of Terms

image

A live snaphot of a machine containing files and directories from the root of that machine's filesystem.

An image is a chroot-able filesystem, stored in /var/lib/systemimager/images/$NAME.

Examples:

  • /var/lib/systemimager/images/RHEL4/

  • /var/lib/systemimager/images/Ubuntu_7_04/

  • /var/lib/systemimager/images/HPC_1.0/

  • ...

override

Overrides can be used to manage differences from images. A typical use is to customize a "vanilla" image adding some additional packages, but they are commonly used to store and distribute configuration files by si_pushoverrides(8).

Overrides are stored by default in /var/lib/systemimager/overrides/ (this directory can be changed in the configuration file /etc/systemimager.conf). All the files and directories defined inside an override are distributed exactly as they are, that means preserving all the data and also metadata: permissions, ownership, timestamps, etc.

Examples:

  • /var/lib/systemimager/overrides/RHEL4/

  • /var/lib/systemimager/overrides/Compute_config/

  • /var/lib/systemimager/overrides/HPC_1.0_custom/

  • ...

image server

A server that has all the images and overrides available for the installation.

client

A machine to be auto-installed with a (single) selected image.

golden client

A manually-installed, customized machine from which an image is taken for deployment to client systems.

transport

The protocol used to distribute images from the image server to the clients. Different approaches can be used, depending on the particular transport used: push / pull / p2p / ...

Examples: rsync, multicast, rsync over SSH, BitTorrent

autoinstall media

Media that is used to boot an autoinstall client to begin the autoinstall process. Autoinstall media can be a USB disk, a CDROM, the network (via PXE), or the local hard drive of the autoinstall client.

autoinstall script

One or more scripts associated with an image, each unique to a specific partitioning/filesystem/network configuration. The si_getimage(8) command creates an initial autoinstallscript, which can be regenerated later, possibly with different options, using the si_mkautoinstallscript(8) command. The autoinstall script (also called the ".master script") is downloaded and executed by the autoinstall client, and performs most of the autoinstall process. Names of autoinstall scripts begin with the image name and end in .master. For example: my_webserver_image_v1.master

si_getimage(8)

A command run from the image server to pull a system image from a golden client.

si_prepareclient(8)

A command you must run on the golden client immediately prior to running si_getimage(8) on the image server. si_prepareclient(8) prepares the golden client to have its image retrieved and creates an etc/systemimager directory with information about the golden client, such as the disk partitioning scheme(s).

si_clusterconfig(8)

A tool to manage and show the SystemImager cluster topology. By this command is possible to tells your image server which image and overrides to install on the auto-install clients.

si_mkdhcpserver(8)

A command that creates a SystemImager -appropriate /etc/dhcpd.conf file. DHCP can be used to assign IP addresses to autoinstall clients.

si_mkdhcpstatic(8)

A command to modify the /etc/dhcpd.conf file, adding static entries for autoinstall clients based on the IP addresses handed out to these clients by the DHCP server.

si_mkbootserver(8)

A utility that helps to setup and configure a network boot server for SystemImager.

si_updateclient(8)

A command that updates or synchronizes client systems to a new or updated image after the initial autoinstall, enabling software and content distribution.

si_pushoverrides(8)

A command to update and/or keep synchronized clients files, pushing the overrides defined by si_clusterconfig(8) from the image server.