Messenger V2 status

Messenger V2 status

[Ricardo Dias]

Hi,

I've read the current description of the Messenger V2 protocol in http:
//docs.ceph.com/docs/master/dev/msgr2/ and would like to ask some
questions about the current status of this feature.

- What are the problems/limitations of the V1 protocol that V2 is
aiming to solve?

- Is the protocol and message formats described in the document final,
or is this just a draft still subject to discussion?

- Did someone already started the implementation of the V2 protocol?

Thanks,
-- 
Ricardo Dias
Senior Software Engineer - Storage Team
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton,
HRB 21284
(AG Nürnberg)

Re: Messenger V2 status

[Sage Weil]

Hi Ricardo!

On Wed, 11 Oct 2017, Ricardo Dias wrote:
> Hi,
> 
> I've read the current description of the Messenger V2 protocol in http:
> //docs.ceph.com/docs/master/dev/msgr2/ and would like to ask some
> questions about the current status of this feature.
> 
> - What are the problems/limitations of the V1 protocol that V2 is
> aiming to solve?

Mainly,

1- The v1 handshake is not extensible because there isn't a negotiation of 
which features to use (no separate of supported vs required features).

2- v2 lets you multiplex multiple entities across the same 
underlying connection (e.g., a TCP stream).  We plan to host multiple OSDs 
within the same process, and those endpoints may come and go (e.g., if one 
of the OSDs is logically marked down).

> - Is the protocol and message formats described in the document final,
> or is this just a draft still subject to discussion?

Draft.  It underwent a fair bit of discussion a little over a year ago so 
it ought to be reasonable complete, but I'm sure we'll run into 
problems as it is being implemented, or what to change things.

> - Did someone already started the implementation of the V2 protocol?

I don't think so.

Thanks!
sage