Re: [Qemu-devel] Qemu only uses a Qemu File to communicate in two hosts?

[Gary Jordan]

Hi Eric,

Could I find a way for two guests in two hosts to communicate?   Like qemu starts one vm in Host 1 and qemu also starts a vm in Host 2, the vm can share their memory.  Is there some existed way to do that, like remote IPC in qemu?

Thanks for your reply.

---Gary

2014-06-30 17:08 GMT-04:00 Eric Blake <address@hidden>:

On 06/30/2014 03:02 PM, Gary Jordan wrote:
> Hi,
> Does Qemu only use the QEMUFile to load the state of VM after migration?

Normally, yes.  Migration must work as a one-way protocol in the common
case when used with default options.

There is a migration mode that uses RDMA which requires bi-directional
communication in order to speed up aspects of memory migration.  But
this mode is transparent to the guest, and requires you to take extra
steps at both source and destination (along with having an infiniband
connection capable of RDMA communication between the two hosts).

> Is there a way for two vm guests to communicate like two threads or
> processes?

If there is, it has nothing to do with migration.  It sounds like you
are asking about ivshmem and/or virtio; if so, search the archives for
recent discussions on the topic.

--
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org