If the switches have spanning tree protocol (default for most enterprise grade switches), they probably disable the port for 30-60 seconds to make sure there is no loop, and so loading the network driver may unlink the port long enough for the switch to disable the port again for 30-60 seconds. To test for this issue, have you system working, run a constant ping, unplug the network, wait 5 seconds, plug it in and see how long it takes to start working again.
To avoid this problem, I configure most of my switch ports for spanning-tree portfast. Alternatively, it might take upto a minute for dhcp to start working... ----- Original Message ----- > From: "olli hauer" <oha...@gmx.de> > To: SCIENTIFIC-LINUX-USERS@listserv.fnal.gov > Cc: "~Stack~" <i.am.st...@gmail.com> > Sent: Sunday, December 1, 2013 11:36:06 AM > Subject: Re: No DHCP on boot with a fresh install > > On 2013-11-30 20:24, ~Stack~ wrote: > > On 11/30/2013 01:03 PM, Nico Kadel-Garcia wrote: > >> You shouldn't have to install NetworkManager for servers. It is > >> *NOT* > >> your friend. > > > > I agree. However, I have wasted too much time already on this > > problem > > (several hours last night and several again this morning) and > > installing > > NetworkManager is the easy way out at the moment. I need and would > > rather focus my attention on the project and not chasing down a > > DHCP > > problem. It really sucks I have to install so many more unneeded > > packages just to get DHCP to work on boot. Such an absurd problem > > to have. > > > >> Neither is DHCP for servers, since sometimes upstream > >> switches have not yet detected the active device by the time your > >> client has scurried its way through the local host restart. In > >> general, I keep servers set statically, and only set them to DHCP > >> when > >> planning a migration. You might this and see if it brings up the > >> network at boot time reliably. > > > > Agreed. Most of my servers are actually hard set. However, in this > > particular project things would be so much better if I had a > > working > > DHCP at boot. > > > >> If the upstream detection is the issue, put a "sleep 10" in the > >> "start" stanza of /etc/nit.d/network. Amusingly enough, you can > >> even > >> put it in /etc/sysconfig/network-scripts/ifcfg-eth0, although that > >> can > >> get irritating and tools like system-config-network or > >> NetworkManager > >> will happily overwrite it. > > > > Not a bad idea. I just tried it and didn't get it to work. Maybe 10 > > seconds is too short? > > > > I will probably just script something when I have time and shove it > > into > > puppet. However, it seems to me that others are also having/seen > > this > > problem. Maybe this should be something fixed upstream? > > > > Thanks for the help everyone! > > ~Stack~ > > Are this bare metal boxes or virtual systems? > > Perhaps you can find a hint with `dmesg' or by disabling the > (annoying) > splash boot so you see what happens when the network is initialized. > > As workaround you can create a simple init script that tries to > detect if the network is up and running (ping GW address) and > executes > ifdown/ifup. > > -- > olli >
