Re: [Qemu-devel] Re: [PATCH 3/5] QMP: Introduce MIGRATION events

[Daniel P. Berrange]

On Tue, May 25, 2010 at 05:35:53PM +0200, Juan Quintela wrote:
> Anthony Liguori <address@hidden> wrote:
> 
> >> +Example:
> >> +
> >> +{ "event": "MIGRATION_FAILED",
> >> +    "timestamp": {"seconds": 1274687575, "microseconds": 592483} }
> >> +
> >> +MIGRATION_STARTED
> >> +-----------------
> >> +
> >> +Emitted when migration starts (both in source and target).
> >>    
> >
> > I think this makes more sense as a MIGRATION_CONNECTED event.  It
> > probably should carry peer information too.
> 
> What kind of peer information?
> 
> We have tcp/fd/exec/unix migrations.  calling it CONNECTED vs STARTED, I
> don't care.  But adding information?  Notice that the management
> application knows what it did, I can put the:
> 
>  "exec: gzip -d < /tmp/foo"
> 
> string, but not much more that I can put here.

This is why I think network client CONNECT/DISCONNECT events should be
separate from MIGRATION START/END events. They happen to occur at roughly
the same time if using a TCP / UNIX socket based migration transport,
but CONNECT/DISCONNECT + peer info is meaningless for exec or fd based
migration.


Daniel
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