Subject: Re: [vserver] odd network problem
From: Chuck <chuck@sbbsnet.net>
Date: Sun, 16 Nov 2008 20:15:40 -0500

On Thursday 13 November 2008, Herbert Poetzl wrote:
> On Thu, Nov 13, 2008 at 10:03:42AM -0500, Chuck wrote:
> > i stopped and restarted our openfire server and all was well with that
> > action. however, 2 web servers, one running an older centos and the
> > other running gentoo64 with openrc/baselayout2 both lost any network
> > communication. ips showed present on the host but were unusable even
> 		~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ that is unusual
> 
> > from the host. the ip blocks of the various guests and the host use 3
> > networks on the same nic.
> 
> > i restarted each of those affected servers. when they stopped each    
> > gave this error:                                                      
> 
> > RTNETLINK answers: Cannot assign requested address
> > RTNETLINK answers: Cannot assign requested address
> > 
> > it appears it gave one line for every ip assigned to the guest.
> 
> that happens if the IP is already there (maybe with
> the wrong netmask or so)
> 
> > restarting those 2 vservers cured the problem. these are the only two
> > affected out of the others living on that host.
> 
> this will have removed and re-added the IPs properly
> 
> > i dont think this has anything to do with it but the centos guest was
> > moved to this server by simply tarring its /vservers and /etc/vservers
> > entries. the openfire and gentoo guests were created and configured on
> > this host. no ip addresses clash.
> 
> > the host is running gentoo64 baselayout1 with
> 
> > kernel 2.6.22-vs2.3.0.34-gentoo
> > util-vserver 0.30.215
> > iproute2 version 2.6.22.20070710
> 
> > i am planning on updating the kernel to 2.6.26-vs2.3.0.35.6-gentoo and 
> > baselayout2/openrc but it is on my 'when i get to it' priority list.
> 
> > anyone seen this behavior of stopping a guest and it affecting
> > networking on other guests before? this is new behavior to me.
> 
> well, it is kind of expected, if you are using several
> IPs in the same network (i.e. with a netmask) and without
> secondary propagation, that when you remove the primary,
> all secondaries are gone too (that is a mainline 'feature')
> 
> but I'm not sure that matches what you are seeing, because
> as I said, the secondaries are gone, so they are not supposed
> to show up on the host or anywhere (in this case)
> 

hmm that behavior appears to be different than earlier versions then. 
previously, if i had 5 guests all using the same /24 network but of course 
different ips, shutting one guest down vanished only its ips and the others 
remained functional. now it appears to destroy all networking within that 
global network.  ie:  guest1 may have xxx.xxx.34.23 thru 26 assigned.. guest2 
may be using xxx.xxx.34.56 thru 60.  both /24 , each guest may have other 
networks assigned as well depending on their functions. the networks for the 
most part are not subnetted in any way. that would create a nightmare.

i need this to be able to just shut down the ip addresses involved with the 
downed guest leaving everything else intact.. 

is there some setting maybe in the kernel or a capability or something that 
can do this? maybe with all these upgrades we have done recently i missed 
some setting?

we have 3 /24 blocks assigned to web hosting and they are distributed 
throughout 10 guests according to various customers/assignment rules/website  
purpose etc that we have. so one /24 network may be shared in all 10 guests 
living on the same host. this same network may be shared with other guests on 
other hosts as well.

so if i read this right, i must now be very careful not to put any 2 guests 
sharing the same network on the same host? ugh... literally impossible with 
our setup.


> best,
> Herbert
> 
> > -- 
> > 
> > Chuck
> 



-- 

Chuck