[Lxc-users] Networking issues with LXC

Daniel Lezcano daniel.lezcano at free.fr
Wed Feb 10 21:21:36 UTC 2010

Daniel Lezcano wrote:
> Michael B. Trausch wrote:
>> Hello,
>> I am running LXC version 0.6.5, with kernel  I am having some 
>> pretty significant troubles getting networking to reliably work with the 
>> containers.  That is to say, the host name is doing just fine, and 
>> answers network requests all the time.  However, the containers 
>> sometimes fail to respond to network for requests for several seconds 
>> and several connection attempts.  This isn't a problem in that it's 
>> rejecting connections on the ports specifically; it's as if there is no 
>> machine on my network with the IP address assigned to the container, 
>> until it comes alive again and answers the network.
>> If I work with a container after getting a connection, I can reach that 
>> container for several minutes (usually---sometimes it will cut off a 
>> connection, though, and then it is again as if that IP address doesn't 
>> exist on my network).
>> I'm out of options as far as getting this working:  This network 
>> configuration works with containers under OpenVZ or full virtual 
>> machines in KVM, where the virtualized network cards are attached to the 
>> bridge.  The IP configuration is handed out by DHCP, (except for my 
>> public IP addresses, which are manually assigned) and the IP addresses, 
>> netmasks, default routes, gateways, broadcast addresses, and so forth 
>> are all correct.  Nonetheless, the networking is *extremely* unreliable.
>> I don't know how to provide additional information to attempt to work 
>> through a problem like this; any guidance in this area would be greatly 
>> appreciated.
> Mmh, hard to answer.
> Can you give the following information:
>  * how many containers are running on the host ?
> For the host and the containers:
>  * 'ip addr show'
>  * ip neigh show
>  * 'brctl show'
> And a tcpdump :
>  tcpdump -i any dst or src <containerip>
> And then try to ping or  connect to/from the container to make tcpdump 
> show something.

Oh ! I forgot the container configurations too, please.

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