[Devel] Re: [RFC] network namespaces

[Cedric Le Goater]

Eric W. Biederman wrote:
>> This family of containers are used too for HPC (high performance computing) and
>> for distributed checkpoint/restart. The cluster runs hundred of jobs, spawning
>> them on different hosts inside an application container. Usually the jobs
>> communicates with broadcast and multicast.
>> Application containers does not care of having different MAC address and rely on
>> a layer 3 approach.
> 
> Ok I think to understand this we need some precise definitions.
> In the normal case it is an error for a job to communication with a different
> job.  

hmm ? What about an MPI application ?

I would expect each MPI task to be run in its container on different nodes
or on the same node. These individual tasks _communicate_ between each
other through the MPI layer (not only TCP btw) to complete a large calculation.

> The basic advantage with a different MAC is that you can found out who the
> intended recipient is sooner in the networking stack and you have truly
> separate network devices.  Allowing for a cleaner implementation.
> 
> Changing the MAC after migration is likely to be fine.

indeed.

C.