I have seen this caused by MAC address caching. After a migration
completes, try checking your machine's arp cache like so for the host in
quetion:
arp -a
If your MAC is cached, try running something like this to see if it clears
up the issue:
arp -d <hostname_or_ip>
ping -c 3 -w 1 <hostname_or_ip>
In a RHCS clustered environment, you can add these to the /usr/share/
cluster.vm.sh script to automate the task when you use "clusvcadm -M" to
migrate your guests.
I updated my "migrate" function in vm.sh like so on all my hosts:
migrate()
{
declare target=$1
# change here to add "--live to xm migrate
xm migrate --live $OCF_RESKEY_name $target
# change here to store return value of xm migrate
rv=$?
# added these three lines to clear the network mac cache
# since our bridges don't (and shouldn't) participate in
# spanning tree
arp -d $OCF_RESKEY_name > /dev/null 2>&1 || true
arp -d ${OCF_RESKEY_name}.FQDN > /dev/null 2>&1 || true
ping -c 1 -w 1 $OCF_RESKEY_name > /dev/null 2>&1 || true
# now return the return code from xm migrate rather tha
# the arp/ping return codes
return ${rv}
}
Hope this helps,
-Dave.
On Fri, Jul 11, 2008 at 10:18 AM, Collins, Kevin [Beeline] <
[EMAIL PROTECTED]> wrote:
> Hi,
>
> I am just starting tests of Xen live migrations and I am seeing
> something weird. I initiated a ping from the DomU was about to migrate, saw
> that it was working and then initiated a migration (from node0 to node1).
> Once the DomU was running on the other node, the ping was hanging. I
> migrated back (node1 to node0) and it started working again. Futher tests
> back and forth proved this to be consistent.
>
> I then shutdown the DomU and rebooted node0 and node1. This time I
> initially started the DomU on node1 and pinging was working. Following the
> same test as above, I found similar results - the ping would work when
> running from node1, not from node0. Both of the Dom0 nodes and the DomU are
> RHEL5.2...
>
> During this process, I assumed some iptables magic happening behind the
> scenes. It appears as if the VIF in the iptables rules is changing each time
> the node migrates (see the "PHYSDEV" line):
>
> root# iptables -L
> Chain INPUT (policy ACCEPT)
> target prot opt source destination
> ACCEPT udp -- anywhere anywhere udp dpt:domain
>
> ACCEPT tcp -- anywhere anywhere tcp dpt:domain
>
> ACCEPT udp -- anywhere anywhere udp dpt:bootps
>
> ACCEPT tcp -- anywhere anywhere tcp dpt:bootps
>
>
> Chain FORWARD (policy ACCEPT)
> target prot opt source destination
> ACCEPT all -- anywhere 192.168.122.0/24 state
> RELATED,ESTABLISHED
> ACCEPT all -- 192.168.122.0/24 anywhere
> ACCEPT all -- anywhere anywhere
> REJECT all -- anywhere anywhere reject-with
> icmp-port-unreachable
> REJECT all -- anywhere anywhere reject-with
> icmp-port-unreachable
> ACCEPT all -- anywhere anywhere PHYSDEV match
> --physdev-in vif1.0
>
> Chain OUTPUT (policy ACCEPT)
> target prot opt source destination
>
> root# iptables -L
> Chain INPUT (policy ACCEPT)
> target prot opt source destination
> ACCEPT udp -- anywhere anywhere udp dpt:domain
>
> ACCEPT tcp -- anywhere anywhere tcp dpt:domain
>
> ACCEPT udp -- anywhere anywhere udp dpt:bootps
>
> ACCEPT tcp -- anywhere anywhere tcp dpt:bootps
>
>
> Chain FORWARD (policy ACCEPT)
> target prot opt source destination
> ACCEPT all -- anywhere 192.168.122.0/24 state
> RELATED,ESTABLISHED
> ACCEPT all -- 192.168.122.0/24 anywhere
> ACCEPT all -- anywhere anywhere
> REJECT all -- anywhere anywhere reject-with
> icmp-port-unreachable
> REJECT all -- anywhere anywhere reject-with
> icmp-port-unreachable
> ACCEPT all -- anywhere anywhere PHYSDEV match
> --physdev-in vif2.0
>
> Chain OUTPUT (policy ACCEPT)
> target prot opt source destination
>
> Has anyone seen this before? The DomU seems to be fine other than that - I
> can login in to it remotely and it seems functionally on the network...
>
> Thanks,
>
> Kevin
>
> _______________________________________________
> rhelv5-list mailing list
> [email protected]
> https://www.redhat.com/mailman/listinfo/rhelv5-list
>
>
--
Dave Costakos
mailto:[EMAIL PROTECTED]
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