I have a question about a Xen host that runs dhcpd and installing guest/running guest VMs (that use DHCP)...
On other hosts or hosts running VMs, they are absolutely able to get DHCP addresses no trouble... However, the fun begins when the machine I run dhcpd on is also hosting VMs. I can see in /var/log/messages the request and ack from dhcpd but the guest VM never hears it. If I should bounce dhcpd prior to a guest install or start a guest VM - everything works just fine.
I'm guessing, perhaps, there is some iptables rule I need to set up? Based on the init scripts, dhcpd definitely starts before xend and xendomains and ultimately the xen bridge...
Anybody know what I need to do :) I've been bouncing dhcpd in /etc/rc.local and starting any VMs there. Although annoying, I'd rather do it "right" so I can auto start my Xen guests...
Thanks ahead of time!
Scot P. Floess 27 Lake Royale Louisburg, NC 27549
252-478-8087 (Home) 919-890-8117 (Work)
Chief Architect JPlate http://sourceforge.net/projects/jplate Chief Architect JavaPIM http://sourceforge.net/projects/javapim
Architect Keros http://sourceforge.net/projects/keros
Scot:
I have a question about a Xen host that runs dhcpd and installing guest/running guest VMs (that use DHCP)...
I think you can run a DHCP server on the host for the guests to grab an IP address from.
Neil
-- Neil Aggarwal, (281)846-8957, http://www.JAMMConsulting.com CentOS 5.4 KVM VPS $55/mo, no setup fee, no contract, dedicated 64bit CPU 1GB dedicated RAM, 40GB RAID storage, 500GB/mo premium BW, Zero downtime
Neil:
Yes - you definitely can...and I am...
The problem is, unless I bounce dhcpd before and guest VM work, the guests don't get the DHCP address...
It's weird ;) But definitely, if I bounce dhcpd (of course after xend/xendomains start) everything works fine - as in the dhcp addresses are received by the guest VMs...
On Fri, 6 Nov 2009, Neil Aggarwal wrote:
Scot:
I have a question about a Xen host that runs dhcpd and installing guest/running guest VMs (that use DHCP)...
I think you can run a DHCP server on the host for the guests to grab an IP address from.
Neil
-- Neil Aggarwal, (281)846-8957, http://www.JAMMConsulting.com CentOS 5.4 KVM VPS $55/mo, no setup fee, no contract, dedicated 64bit CPU 1GB dedicated RAM, 40GB RAID storage, 500GB/mo premium BW, Zero downtime
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Scot P. Floess 27 Lake Royale Louisburg, NC 27549
252-478-8087 (Home) 919-890-8117 (Work)
Chief Architect JPlate http://sourceforge.net/projects/jplate Chief Architect JavaPIM http://sourceforge.net/projects/javapim
Architect Keros http://sourceforge.net/projects/keros
Scot:
The problem is, unless I bounce dhcpd before and guest VM work, the guests don't get the DHCP address...
That is very strange behavior. I use KVM with static IPs so I don't think I can be much help.
Have you tried posting this to the CentOS-virt list?
Neil
-- Neil Aggarwal, (281)846-8957, http://www.JAMMConsulting.com CentOS 5.4 KVM VPS $55/mo, no setup fee, no contract, dedicated 64bit CPU 1GB dedicated RAM, 40GB RAID storage, 500GB/mo premium BW, Zero downtime
Hee - no. I just joined the CentOS mailing list today... I'll subscribe to that list and see...
Thanks!
On Fri, 6 Nov 2009, Neil Aggarwal wrote:
Scot:
The problem is, unless I bounce dhcpd before and guest VM work, the guests don't get the DHCP address...
That is very strange behavior. I use KVM with static IPs so I don't think I can be much help.
Have you tried posting this to the CentOS-virt list?
Neil
-- Neil Aggarwal, (281)846-8957, http://www.JAMMConsulting.com CentOS 5.4 KVM VPS $55/mo, no setup fee, no contract, dedicated 64bit CPU 1GB dedicated RAM, 40GB RAID storage, 500GB/mo premium BW, Zero downtime
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Scot P. Floess 27 Lake Royale Louisburg, NC 27549
252-478-8087 (Home) 919-890-8117 (Work)
Chief Architect JPlate http://sourceforge.net/projects/jplate Chief Architect JavaPIM http://sourceforge.net/projects/javapim
Architect Keros http://sourceforge.net/projects/keros
Scot P. Floess wrote on Fri, 6 Nov 2009 10:20:34 -0500 (EST):
Hee - no. I just joined the CentOS mailing list today... I'll subscribe to that list and see...
You should find (in the archives of that list) a longer discussion between me and Ross Walker (I think) about this problem (last year?). At that time it was clearly a bug in the Xen network setup script that I fixed with a few edits. As I'm using mostly static addresses (dhcp was only used for experiments with kickstarting installations that were to be discarded, anyway) I don't know if the same problem still exists. Another option might be to just forget about the Xen network script and do your own bridging which should then workaround this problem as well. I did that this year because of another problem with the Xen network script. There should be a later discussion about how to do this from this year.
Kai
OK - I'll look through the list and see if I can find the discussion :)
On Fri, 6 Nov 2009, Kai Schaetzl wrote:
Scot P. Floess wrote on Fri, 6 Nov 2009 10:20:34 -0500 (EST):
Hee - no. I just joined the CentOS mailing list today... I'll subscribe to that list and see...
You should find (in the archives of that list) a longer discussion between me and Ross Walker (I think) about this problem (last year?). At that time it was clearly a bug in the Xen network setup script that I fixed with a few edits. As I'm using mostly static addresses (dhcp was only used for experiments with kickstarting installations that were to be discarded, anyway) I don't know if the same problem still exists. Another option might be to just forget about the Xen network script and do your own bridging which should then workaround this problem as well. I did that this year because of another problem with the Xen network script. There should be a later discussion about how to do this from this year.
Kai
-- Kai Schätzl, Berlin, Germany Get your web at Conactive Internet Services: http://www.conactive.com
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Scot P. Floess 27 Lake Royale Louisburg, NC 27549
252-478-8087 (Home) 919-890-8117 (Work)
Chief Architect JPlate http://sourceforge.net/projects/jplate Chief Architect JavaPIM http://sourceforge.net/projects/javapim
Architect Keros http://sourceforge.net/projects/keros
Scot P. Floess wrote on Fri, 6 Nov 2009 12:46:35 -0500 (EST):
OK - I'll look through the list and see if I can find the discussion :)
I think you actually found it already. It's on the xen list and not on centos-virt, sorry. But you will find a related thread about problems with xenbr0 on centos-virt just a few days earlier. Maybe it gives you some hints if you read both. I'm not sure if I solved this problem.
Kai
Thanks! As it stands now, if I bounce dhcpd and then xme create's in /etc/rc.local it works fine. Just felt like a hack ;)
I'll definitely be looking at it off and on till I figure it out :)
On Sat, 7 Nov 2009, Kai Schaetzl wrote:
Scot P. Floess wrote on Fri, 6 Nov 2009 12:46:35 -0500 (EST):
OK - I'll look through the list and see if I can find the discussion :)
I think you actually found it already. It's on the xen list and not on centos-virt, sorry. But you will find a related thread about problems with xenbr0 on centos-virt just a few days earlier. Maybe it gives you some hints if you read both. I'm not sure if I solved this problem.
Kai
-- Kai Schätzl, Berlin, Germany Get your web at Conactive Internet Services: http://www.conactive.com
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Scot P. Floess 27 Lake Royale Louisburg, NC 27549
252-478-8087 (Home) 919-890-8117 (Work)
Chief Architect JPlate http://sourceforge.net/projects/jplate Chief Architect JavaPIM http://sourceforge.net/projects/javapim
Architect Keros http://sourceforge.net/projects/keros
Kai Schaetzl wrote on Fri, 06 Nov 2009 18:31:22 +0100:
Another option might be to just forget about the Xen network script and do your own bridging which should then workaround this problem as well. I did that this year because of another problem with the Xen network script. There should be a later discussion about how to do this from this year.
MID VA.000037de.0716d4cd@news.conactive.com on the xen-users list. I'm using this bridging setup on all my Xen machines now and have switched off the network-bridge script.
Kai
Hey thanks again!
On Fri, 6 Nov 2009, Kai Schaetzl wrote:
Kai Schaetzl wrote on Fri, 06 Nov 2009 18:31:22 +0100:
Another option might be to just forget about the Xen network script and do your own bridging which should then workaround this problem as well. I did that this year because of another problem with the Xen network script. There should be a later discussion about how to do this from this year.
MID VA.000037de.0716d4cd@news.conactive.com on the xen-users list. I'm using this bridging setup on all my Xen machines now and have switched off the network-bridge script.
Kai
-- Kai Schätzl, Berlin, Germany Get your web at Conactive Internet Services: http://www.conactive.com
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Scot P. Floess 27 Lake Royale Louisburg, NC 27549
252-478-8087 (Home) 919-890-8117 (Work)
Chief Architect JPlate http://sourceforge.net/projects/jplate Chief Architect JavaPIM http://sourceforge.net/projects/javapim
Architect Keros http://sourceforge.net/projects/keros
Sorry, I meant to say "unless I bounce dhcpd before the guest VMs are started, the guests don't get the DHCP address" - meaning they don't "hear" the ack...
Silly type-o - should proof read before I post ;)
On Fri, 6 Nov 2009, Scot P. Floess wrote:
Neil:
Yes - you definitely can...and I am...
The problem is, unless I bounce dhcpd before and guest VM work, the guests don't get the DHCP address...
It's weird ;) But definitely, if I bounce dhcpd (of course after xend/xendomains start) everything works fine - as in the dhcp addresses are received by the guest VMs...
On Fri, 6 Nov 2009, Neil Aggarwal wrote:
Scot:
I have a question about a Xen host that runs dhcpd and installing guest/running guest VMs (that use DHCP)...
I think you can run a DHCP server on the host for the guests to grab an IP address from.
Neil
-- Neil Aggarwal, (281)846-8957, http://www.JAMMConsulting.com CentOS 5.4 KVM VPS $55/mo, no setup fee, no contract, dedicated 64bit CPU 1GB dedicated RAM, 40GB RAID storage, 500GB/mo premium BW, Zero downtime
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Scot P. Floess 27 Lake Royale Louisburg, NC 27549
252-478-8087 (Home) 919-890-8117 (Work)
Chief Architect JPlate http://sourceforge.net/projects/jplate Chief Architect JavaPIM http://sourceforge.net/projects/javapim
Architect Keros http://sourceforge.net/projects/keros _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Scot P. Floess 27 Lake Royale Louisburg, NC 27549
252-478-8087 (Home) 919-890-8117 (Work)
Chief Architect JPlate http://sourceforge.net/projects/jplate Chief Architect JavaPIM http://sourceforge.net/projects/javapim
Architect Keros http://sourceforge.net/projects/keros
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Kai Schaetzl -
Neil Aggarwal -
Scot P. Floess