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Basic Design Concepts
System Installation Suite is image-based. An image is the
template for an installed client, it contains the unconfigured
operating system plus the applications and any data specific
to that type of machine. These images are stored on a central
server, or servers. From there another system is used to
propogate the raw image data from the server to the client
workstation or workstations. Once the data is present on the
client, a configuration tool is called to setup the unique
aspects of that particular workstation. Mostly this will
involve things like network and hardware configuration, and
boot loader installation.
In particular, since applications and resources are stored
as part of the image, there might be an image for a central
webserver or a generic node in a web farm, another one for DNS
master or slave servers, and yet another for the nodes in a
1000 cpu Beowulf cluster. You would not need different
images, however, for clients of the same architecture that are
all intended to provide the same services but differ in ide or
scsi/raid hard drive systems, network type (ethernet, token
ring, gigabit, etc) or network card, or other
hardware-specific differences.
System Installation Suite can then be divided into three
phases, with a software project devoted to each phase:
- System Installer
- System Installer handles the creation of the images
themselves, along with storing all the pertinent
information for the rest of the system. In the near
future, it must deal with such complexities as creating
images of RedHat 7.1 and Suse 7.0 from a Debian 2.2
system, where RedHat will go on a Compaq Alpha, Suse on a
PPC, with the Debian server running on an x86
architecture. It presents a common CLI for use by other
applications and contains a client GUI application for
simplified use. It can also invoke the second phase of
the install and pass it the necessary information.
- SystemImager
- SystemImager prepares the client for receiving the
image and then propagates the data from the image onto the
client's local media. It is typically done over a
network, but support is in the works for purely cd-based
installs. It must deal with such complexities as bringing
the client up onto the network, configuring local media
for the image and transmitting the image from the server.
And it must be able to boot and prepare a variety of
architectures and scale to a large number of simultaneous
installs. It also invokes the last phase of the install,
and passes it the necessary information.
- System Configurator
- System Configurator modifies the newly transmitted
image so that when the machine is rebooted it will come up
onto the network as a useful working machine. It must
deal with such complexities as configuring and installing
the present hardware, preparing and installing the
necessary boot loader, and configuring the network and
other unique aspects of individual workstations. It has
to provide an infrastructure that makes it easy to add
support for multiple operating systems and multiple
distributions along with multiple versions of said
operating systems and distributions while doing so across
as many architectures as it can.
For more information read the SIS Application
Stack page. It explains some of the ways that other applications
can fit into the SIS framework.
Last modified: Sun Mar 31 20:41:11 EST 2002
by Sean Dague
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