Rolling Out Linux - page 5
Distribution makers also have their own special methods for installing Linux to many machines. An example of one of these methods is the Redhat Kickstart system. All Kickstart does is make a script to pick the options in the standard Redhat install screen automatically. There is even a web site which will make the bootdisks to do this for you.
Once the machines are live on the net most distributions allow updates to happen over the net from remote sites. If this is not practical then package updates can occur with either a combination of a remote shell system like ssh and a package manager or via NFS from local server with updated packages.
Managing networks of distributed Linux machines once they are running is relatively easy as (almost) everything except the kernel may be replaced or reconfigured without even rebooting.