Hello
I have a physical server (Dell Poweredge 1950III) running current CentOS 5.4 x86_64 and the XEN hypervisor, provided by CentOS.
This machine has 2 virtual machines installed, both with CentOS 5.4 x86_64.
Unfortunatly SSH connections coming both, from an external machine or from DOM0, regularly stall, for a period of some minutes. In other words, while working through SSH, at a given moment everything freezes and after some minutes thaws again.
We have several other machines with similar hardware/software configurations, but none of these has similar stalls.
Anyway, when attaching the console with "xm console <vm-name>" there are no stalls at all.
Does anybody have any suggestion on where to start to trouble shoot this problem?
Regards,
Peter
Ive seen this happen in some distros when the option 'UseDNS' is set to yes in the file sshd_config
Of course, there could be issues with your network setup as well...
compdoc wrote:
Ive seen this happen in some distros when the option 'UseDNS' is set to yes in the file sshd_config
Of course, there could be issues with your network setup as well...
CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Nothing seems to change. Indeed, also pinging the guest has the same problems. I'm also monitoring this machine since this morning and services are up and down and I can not understand why.
iptables on dom0 and vm guest are, at the moment, turned off.
Summarizing:
1. This happens on all XEN guests on this physical server, except dom0. It does not happen on any other server/xen guest.
2. Outgoing network connections are fine.
3. xm console <xen_guest> works fine.
Peter
----- "Peter Hopfgartner" peter.hopfgartner@r3-gis.com wrote:
Nothing seems to change. Indeed, also pinging the guest has the same problems. I'm also monitoring this machine since this morning and services are up and down and I can not understand why.
iptables on dom0 and vm guest are, at the moment, turned off.
Summarizing:
- This happens on all XEN guests on this physical server, except
dom0. It does not happen on any other server/xen guest.
Outgoing network connections are fine.
xm console <xen_guest> works fine.
Peter
While you're pinging when it isn't working, do the packets at least get to dom0? Is ARP working during that time? Are you using NAC or anything funky on its switch?
Christopher G. Stach II wrote:
----- "Peter Hopfgartner" peter.hopfgartner@r3-gis.com wrote:
Nothing seems to change. Indeed, also pinging the guest has the same problems. I'm also monitoring this machine since this morning and services are up and down and I can not understand why.
iptables on dom0 and vm guest are, at the moment, turned off.
Summarizing:
- This happens on all XEN guests on this physical server, except
dom0. It does not happen on any other server/xen guest.
Outgoing network connections are fine.
xm console <xen_guest> works fine.
Peter
While you're pinging when it isn't working, do the packets at least get to dom0? Is ARP working during that time? Are you using NAC or anything funky on its switch?
Hmmm, starting with your suggestion, I seen that both domU had the same mac. As by now, I think that this was the root of my problems.
Thanks,
Peter
-
Christopher G. Stach II -
compdoc -
Peter Hopfgartner