At Mon, 11 Jul 2011 16:17:24 -0700 CentOS mailing list centos@centos.org wrote:
(I'm doing tests in a VirtualBox instance, so take this with a grain of salt.)
If you give the VM only 512 MB of RAM, the text-mode installer kicks in. It does not prompt you to configure anything related to the network or hostname. The system boots up without a network interface configured. Also, it won't let you choose the install mode, I guess it defaults to Minimal (which is fine by me, but still it's a bug).
If you give the VM 768 MB of RAM, the GUI installer is launched, and this one allows you to configure the hostname, the networking details, and choose the install mode. The system boots up with networking and all the niceties enabled.
I don't know if this relates or not, but attempting to install FC15 in a VM with only 512M of memory, fails: the kernel / installer hangs. It looks like the minimum memory requirements to install FC15 (and it looks like RHel / CentOS 6 as well) is something greater than 512meg and probably something closer to 1G.