Re: [RFC 4/6] migration: Deprecate -incoming <uri>
Peter Xu <peterx(a)redhat.com> wrote:
On Mon, Jun 12, 2023 at 10:51:08PM +0200, Juan Quintela wrote:
> Peter Xu <peterx(a)redhat.com> wrote:
> > On Mon, Jun 12, 2023 at 09:33:42PM +0200, Juan Quintela wrote:
> >> Only "defer" is recommended. After setting all migation
parameters,
> >> start incoming migration with "migrate-incoming uri" command.
> >>
> >> Signed-off-by: Juan Quintela <quintela(a)redhat.com>
> >> ---
> >> docs/about/deprecated.rst | 7 +++++++
> >> softmmu/vl.c | 2 ++
> >> 2 files changed, 9 insertions(+)
> >>
> >> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
> >> index 47e98dc95e..518672722d 100644
> >> --- a/docs/about/deprecated.rst
> >> +++ b/docs/about/deprecated.rst
> >> @@ -447,3 +447,10 @@ The new way to modify migration is using migration
parameters.
> >> ``blk`` functionality can be acchieved using
> >> ``migrate_set_parameter block-incremental true``.
> >>
> >> +``-incoming uri`` (since 8.1)
> >>
+'''''''''''''''''''''''''''''
> >> +
> >> +Everything except ``-incoming defer`` are deprecated. This allows to
> >> +setup parameters before launching the proper migration with
> >> +``migrate-incoming uri``.
> >> +
> >> diff --git a/softmmu/vl.c b/softmmu/vl.c
> >> index b0b96f67fa..7fe865ab59 100644
> >> --- a/softmmu/vl.c
> >> +++ b/softmmu/vl.c
> >> @@ -2651,6 +2651,8 @@ void qmp_x_exit_preconfig(Error **errp)
> >> if (incoming) {
> >> Error *local_err = NULL;
> >> if (strcmp(incoming, "defer") != 0) {
> >> + warn_report("-incoming %s is deprecated, use -incoming
defer and "
> >> + " set the uri with migrate-incoming.",
incoming);
> >
> > I still use uri for all my scripts, alongside with "-global
migration.xxx"
> > and it works.
>
> You know what you are doing (TM).
> And remember that we don't support -gobal migration.x-foo.
> Yes, I know, we should drop the "x-" prefixes.
I hope they'll always be there. :) They're pretty handy for tests, when we
want to boot a VM without the need to script the sequences of qmp cmds.
Yes, we probably should just always drop the x-. We can always declare
debugging purpose for all -global migration.* fields.
>
> > Shall we just leave it there? Or is deprecating it helps us in any form?
>
> See the patches two weeks ago when people complained that lisen(.., num)
> was too low. And there are other parameters that work the same way
> (that I convenientely had forgotten). So the easiest way to get things
> right is to use "defer" always. Using -incoming "uri" should
only be
> for people that "know what they are doing", so we had to ways to do it:
> - review all migration options and see which ones work without defer
> and document it
> - deprecate everything that is not defer.
>
> Anything else is not going to be very user unfriendly.
> What do you think.
IIRC Wei Wang had a series just for that, so after that patchset applied we
should have fixed all issues cleanly?
No, what he does is using always a very big value for listen. But that
is it. Anyways, I don't know how to change the backlog listen value
without restarting the listen call.
Is there one more thing that's not
working right there?
Compression has other problems. But independentely of that, they have
the problem that we need to set the parameters before we call incoming.
> PD. This series are RFC for multiple reasons O:-)
Happy to know the rest (besides which I know will break my script :).
Thanks, Juan.