Thanks, Nish. In answer to your questions:
(1) These machines are in a farm of many tens of machines, so we need things to be automatic wherever possible. Unnecessary differences need to be avoided. Our multiple network interfaces are on different networks, so the automation is to configure each particular interface (ideally constant "n" in "ethn") on each network. For a given network, each machine should use its "eth<n>", fixed "<n>". In such a farm it is poor practice, and non-scalable to have to sign on to each machine to set up interfaces differently from other machines, simply because the installation process had been inconsistent. (2) Custom udev would apply to RHEL6 wouldn't it? But this is RHEL5. Is custom udev available at all for network interfaces on RHEL5? It seems instead to be kudzu and /etc/sysconfig/hwconf. And that doesn't seem to be settable in advance. (3) [Use of MAC]. I believe that ultimately the "ifcfg-eth*" files need the MAC. That's OK. I'm talking about the stage before that, when the system examines its hardware and by some process that is, sadly, non-deterministic, it maps the "eth*" names onto those findings. Finally... is it cobbler-specific? OK, the details we are discussing are not cobbler-specific. But it seems that the best environment to run this is within the post-install section of cobbler, before the just-installed system is booted. Thanks again,. -- David Lee ----- Original Message ----- From: "Nishanth Aravamudan" <[email protected]> To: "David Lee" <[email protected]> Cc: "cobbler mailing list" <[email protected]> Sent: Thursday, 20 September, 2012 6:11:27 PM Subject: Re: [cobbler] fixing "ifcfg-eth*" to particular hardware Hi David, On 20.09.2012 [17:50:52 +0100], David Lee wrote: > Cobbler version: 2.0.11 (actually 2.0.11-2 from RPM) > All systems: RHEL 5.8 > > > [Preliminary: I realise our cobbler version is a little old. I'd > rather not have to upgrade right now, but if it really would make a > substantial difference to the problem I am about to describe, that > could be done.] > > We install RHEL 5.8 on many IBM boxes, which are all very similar. In > particular there are four ethernet ports on the system itself, and a > separate board with two 10-Gig ports. > > The first ethernet port is our provisioning network, over which > cobbler runs. During installation, it seems to call this "eth2". But > after installation it almost always comes up as "eth0". (That's OK > (although I don't understand it!) but it might interact slightly with > the real problem below.) Moving on... > > After installation, the four system ethernet ports usually get > assigned names eth0, eth1, eth2 and eth3, usually in order. (The > cobbler/provisioning interface seems to get "eth0" always.) The two > 10-Gig ports get assigned names eth4 and eth5... usually. > > But occasionally (perhaps 10% or slightly more) an installation ends > up with a different mapping of names to ports. (If we then > re-install, it usually gets the expected mapping.) That is a problem > when one is (re-)installing machines in a farm of machines that are > supposed to be the same. So a couple of questions spring to mind. 1) Is the naming somehow critical to your application? I assume so, because I'm not sure why it's relevant otherwise. 2) If you want static naming of interfaces, I believe the right way of doing this is custom udev rules (which you might install via cobbler). 3) I think the normal way for this to work is to always use the MAC address to identify the physical port. > I realise that "cobbler system" has a "--interface" capability. But I > don't see a way for that to be used to map specific names to specific > hardware. > > I make no claims to understand the depths and intricacies of > "/etc/modprobe.conf", "/etc/sysconfig/hwconf", kudzu, etc. But is > there a way (or common practice) somehow to pre-populate various > things with relevant information for the mapping of generated "eth*" > names onto particular ethernet ports? This isn't really a Cobbler specific question, afaict. I would look into udev rules, probably, if relevant. Thanks, Nish _______________________________________________ cobbler mailing list [email protected] https://lists.fedorahosted.org/mailman/listinfo/cobbler
