>> From: "John Ford" <jf...@nrao.edu> >> Date: 20 December 2011 00:38:40 SAST >> To: casper@lists.berkeley.edu >> Subject: [casper] [Fwd: Re: [Helpdesk #4625] [Fwd: reboot roach1 and >> 3?]] >> >> Hi All. >> >> Anyone know if the DHCP setup on ROACH 1 renews its lease? I'm woefully >> ignorant of all things DHCP... > > Hello > > Roaches get the kernel to issue DHCP/BOOTP requests at bootup (kernel > level IP autoconfiguration - if the NFS boot option is selected). This > is needed otherwise the kernel won't find its NFS server and so can't > mount root (/). So we have had no reason to run a userspace > dhcp client, but also explains the problems you are seeing (sorry).
This is what I suspected. > > I believe you can run a normal userspace dhcp client, but you need > to be aware of a small wrinkle: The dhcp clients I have used > deconfigured the interfaces while they were negotiating leases, > which can be bad if the roach also needs to perform file system IO to the > NFS server at that point (a problem which might not always happen > as things do get cached). Yeah, I tried this with the existing dhclient, and it went in the weeds... > There could be a dhcp client config file > or commandline option somewhere to deal with this, or maybe a > special dhcp client, but I haven't had a reason to look into > it (our correlator has its own subnet and assignments are static), > though I concede that ignoring lease expiries isn't great form. Yes, I think we'll go for some static addresses and forget about this for now. Thanks, Marc! John
