Recently I've discovered a secret feature in AutoYaST. Well, probably not so secret, because a SLES11 user (from our Two-Letter Customer) discovered it as well and reported a bug about it :) But all in all, if you googled for the keyword (keep_install_network) a week ago, the only hits were an AutoYaST changelog with short notice "I've added this feature" and few questions about it on opensuse-autoinstall mailing list. The documentation did not reveal any more details.

So - what does keep_install_network parameter, set to 'true' and inserted into <networking> section of AutoYaST profile, do? One can intuitively guess that it will preserve network configuration - that is, interfaces setup, resolv.conf bits, static routing, udev rules & co. - from 1st stage of installation (of course, only if the installation actually runs over the network) and it is indeed like that. Uwe blogs about it in more details

But unless you use openSUSE Factory, please don't try this at home :)

<networking>
  <keep_install_network config:type="boolean">true</keep_install_network>
</networking>

Network interfaces setup (ifcfg files) from the installation will be successfully preserved, but due to a bug, your static routing configuration (if you have any) will be moved into backup file and YaST won't create a new one and you will lose most of the information in /etc/resolv.conf. Unfortunately, nobody got the idea to test with the profile containing nothing more but keep_install_network entry in networking section so far :(

The bug is fixed now for openSUSE 11.2 and SLE11 SP1 (if nothing in particular sub-section of networking section is defined, the setup from installation is used, but AutoYaST profile is the higher authority here). However, if you use SLE11, you'd better install with profile containing at least minimal DNS and routing info, for example like this (set search domain, 1 nameserver and default gateway):

<networking>
    <keep_install_network config:type="boolean">true</keep_install_network>
    <dns>
      <dhcp_hostname config:type="boolean">false</dhcp_hostname>
      <domain>home.net</domain>
      <hostname>dolphin</hostname>
      <nameservers config:type="list"> 
        <nameserver>192.168.0.2</nameserver>
      </nameservers>
      <searchlist config:type="list">
        <search>home.net</search>
      </searchlist>
    </dns>
    <routing>
      <ip_forward config:type="boolean">false</ip_forward>
      <routes config:type="list">
        <route>
          <destination>default</destination>
          <device>-</device>
          <gateway>192.168.0.1</gateway>
          <netmask>-</netmask>
        </route>
      </routes>
    </routing>
  </networking>

Or use a workaround post-script Uwe posted to bugzilla, to backup your setup and to restore it later.

One good thing about these bugs is that not only it broadens your knowledge (when user comes up with scenario you never thought of) ;-) but it also helps us to improve things. keep_install_network feature is now documented and not secret anymore. Enjoy it!