Re: VM networking stops working

[Izik Eidus <izike-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Mike wrote:
> Izik Eidus schrieb:
>   
>> Mike wrote:
>>     
>>> Izik Eidus schrieb:
>>>  
>>>       
>>>> Mike wrote:
>>>>    
>>>>         
>>>>> Izik Eidus schrieb:
>>>>>  
>>>>>      
>>>>>           
>>>>>> Mike wrote:
>>>>>>           
>>>>>>             
>>>>>>> Hello,
>>>>>>> I have a problem with my virtual machines. I am using kvm53
>>>>>>> on an AMD Athlon(tm) 64 X2 Dual Core Processor 5000+.
>>>>>>> As distribution I use Ubuntu server 7.10.
>>>>>>> As kernel I use Linux 2.6.22-14-server #1 SMP Sun Oct 14 22:09:15 
>>>>>>> GMT 2007 x86_64 GNU/Linux.
>>>>>>>
>>>>>>> I have 3 different vms running. At the beginning they all work 
>>>>>>> without a problem.
>>>>>>> Then, after one moment to another one or more stop working.
>>>>>>> I did a ping test to all the machines, the vm with the failure 
>>>>>>> stops pinging.
>>>>>>> The result from external ping: Destination host unreachable.
>>>>>>> The same result from a ping onto the main server.
>>>>>>>
>>>>>>> Here are my configuration files:
>>>>>>> cat /etc/qemu-ifup
>>>>>>> #!/bin/sh
>>>>>>> /sbin/ifconfig $1 0.0.0.0 promisc up
>>>>>>> /usr/sbin/brctl addif br0 $1
>>>>>>> sleep 2
>>>>>>> ------------------------------------------------------------------------ 
>>>>>>>
>>>>>>> cat /etc/network/interfaces
>>>>>>> auto lo
>>>>>>> iface lo inet loopback
>>>>>>>
>>>>>>> auto br0
>>>>>>> iface br0 inet static
>>>>>>> address 195.24.77.169
>>>>>>> netmask 255.255.255.0
>>>>>>> gateway 195.24.77.1
>>>>>>> bridge_ports eth0
>>>>>>> bridge_stp off
>>>>>>> bridge_maxwait 5
>>>>>>> ------------------------------------------------------------------------ 
>>>>>>>
>>>>>>> I use scripts for starting the vms:
>>>>>>> kvm -hda apache.img -hdb apache_storage.img -m 512 -boot c -net 
>>>>>>> nic,vlan=0,macaddr=00:16:3e:00:00:01 -net tap -nographic -daemonize
>>>>>>> kvm -hda postfix.img -m 512 -boot c -net 
>>>>>>> nic,vlan=0,macaddr=00:16:3e:00:00:12 -net tap -nographic -daemonize
>>>>>>> kvm -hda openvpn.img -m 256 -boot c -net 
>>>>>>> nic,vlan=0,macaddr=00:16:3e:00:00:03 -net tap -nographic -daemonize
>>>>>>> ------------------------------------------------------------------------ 
>>>>>>>
>>>>>>> The tapN devices are being created at the startup of the vms.
>>>>>>>
>>>>>>> When I run dmesg I have this:
>>>>>>> [  112.390943] br0: port 2(tap1) entering learning state
>>>>>>> [  112.391919] br0: port 3(tap0) entering learning state
>>>>>>> [  112.397605] br0: port 4(tap2) entering learning state
>>>>>>> [  122.674313] tap0: no IPv6 routers present
>>>>>>> [  122.729185] tap1: no IPv6 routers present
>>>>>>> [  122.843901] tap2: no IPv6 routers present
>>>>>>> [  123.336081] kvm: emulating exchange as write
>>>>>>> [  127.367940] br0: topology change detected, propagating
>>>>>>> [  127.367949] br0: port 4(tap2) entering forwarding state
>>>>>>> [  127.362971] br0: topology change detected, propagating
>>>>>>> [  127.362977] br0: port 2(tap1) entering forwarding state
>>>>>>> [  127.362978] br0: topology change detected, propagating
>>>>>>> [  127.362980] br0: port 3(tap0) entering forwarding state
>>>>>>>
>>>>>>> No indication of a problem, nowhere in the log files.
>>>>>>>
>>>>>>> I don't know if the vms are freezing, or the network forwarding 
>>>>>>> stops working.
>>>>>>> I also activated "net.ipv4.conf.default.forwarding=1"
>>>>>>>
>>>>>>> I googled days for that problem, but without a result.
>>>>>>> I hope that maybe you have a solution for this problem. That 
>>>>>>> would be great, because I prefer using kvm instead of other 
>>>>>>> virtualization systems.
>>>>>>>
>>>>>>> Thank you very much in advance,
>>>>>>> Greetings from Luxembourg.
>>>>>>>
>>>>>>> Have a nice day,
>>>>>>> Mike
>>>>>>>                 
>>>>>>>               
>>>>>> it might be not the network that die, but the whole vm
>>>>>> can you run the vms with -vnc ? (first vm -vnc :1 secoend vm -vnc 
>>>>>> :2 third vm -vnc :3)
>>>>>> and try to connect to them with vncviewer and see if they are alive?
>>>>>>
>>>>>>             
>>>>>>             
>>>>> Thank you for your reply.
>>>>> I can't connect to the vm if it has died, even with vnc. I tried 
>>>>> this already, no reply from the host.
>>>>> I don't have physical access to the server because its located in a 
>>>>> dc. Only ssh to the host.
>>>>>         
>>>>>           
>>>> ok this mean there is bug in kvm for amd and it not realted to the 
>>>> network
>>>> what is the guest that you use? is it 64/32?
>>>>
>>>>     
>>>>         
>>> I'm using Debian Etch 32 Bit for all guests
>>> with Kernel Linux apache 2.6.18-5-486 #1 Tue Oct 2 23:38:54 UTC 2007 
>>> i686 GNU/Linux
>>>
>>> ------------------------------------------------------------------------- 
>>>
>>>   
>>>       
>> ok but what more interesting me is:
>> if you run just one vm
>> is it work?
>>     
> Yes. If I run only 1 vm, it runs days without problems.
> I have sometimes have peaks in reply time from the guest.
> e.g.
> bytes=32 time=34ms TTL=57
> bytes=32 time=34ms TTL=57
> bytes=32 time=119ms TTL=57
> bytes=32 time=400ms TTL=57
> bytes=32 time=540ms TTL=57
> bytes=32 time=947ms TTL=57
> bytes=32 time=754ms TTL=57
> bytes=32 time=850ms TTL=57
> bytes=32 time=925ms TTL=57
> bytes=32 time=2032ms TTL=57
> bytes=32 time=897ms TTL=57
> bytes=32 time=197ms TTL=57
> bytes=32 time=34ms TTL=57
> bytes=32 time=34ms TTL=57
>
> but if I ping the host server the same time, the reply time is normal, 
> around 34ms
>
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ok sound interesting,
you are sure you are using kvm53 modules?
(one issue like that solved at kvm53, but maybe we have another one...)

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