Re: [RFC 4/6] migration: Deprecate -incoming <uri>
On Tue, Jun 20, 2023 at 01:10:55PM +0100, Daniel P. Berrangé wrote:
In some cases it is worth having a convenience option for user
friendliness.
In this case, however, users are already needing to use QMP/HMP on the
source side to set migration parameters. I think it is reasonable to say
that doing *exactly* the same with QMP/HMP on the destination side is
actually more friendly than requiring use of -global on the dest side
which is different syntax.
The -global parameters also work for the src side for my scripts, so I only
need to attach "-incoming tcp:XXX" for dst cmdline here.
We don't document the way to use -global with migration parameters so
when people see '-incoming' I think we are steering them into a trap,
making it look like -incoming is sufficient on its own. Hence that user's
mistake recently about not setting migration parameters.
Overall I agree with deprecating '-incoming' != 'defer', as I think it
will better guide users to following the correct steps, as is not a
usability burden as they're already using QMP/HMP on the source side.
I'd say -global is definitely not for users but for developers. Just like
we keep around HMP - I'm not sure whether it's used in productions, I
thought it was only for developers and we don't deprecate it eagerly.
No strong opinions here if everyone wants to get rid of that, but before
that I hope we can have some kind of cmdline tool that can easily tunnel
qmp commands so whoever developers using pure cmdlines can switch to the
new way easily.
Thanks,
--
Peter Xu