Re: [Xen-devel] xend deprecation

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Wed, Sep 04, 2013 at 04:34:30PM +0100, Ian Campbell wrote:
> On Wed, 2013-09-04 at 16:18 +0100, George Dunlap wrote:
> > On Wed, Sep 4, 2013 at 3:04 PM, Konrad Rzeszutek Wilk
> > <konrad.wilk@xxxxxxxxxx> wrote:
> > > On Wed, Sep 04, 2013 at 08:29:07AM +0100, Ian Campbell wrote:
> > >> On Tue, 2013-09-03 at 23:06 -0700, Matt Wilson wrote:
> > >> > On Tue, Sep 03, 2013 at 09:03:46AM +0100, Ian Campbell wrote:
> > >> > > On Mon, 2013-09-02 at 13:32 -0700, Matt Wilson wrote:
> > >> > > > Live migration between a system running xend to a system that 
> > >> > > > doesn't
> > >> > > > support xend would be a nice-to-have. That probably means some 
> > >> > > > support
> > >> > > > for SXP parsing either in libxl or in some compatibility tool.
> > >> > >
> > >> > > This already works by using xl on the source side, e.g. a guest 
> > >> > > started
> > >> > > with xend on 4.1 can be migrated with 4.1's xl to 4.2.
> > >> > >
> > >> > > http://lists.xen.org/archives/html/xen-devel/2012-08/msg02191.html
> > >> >
> > >> > xl doesn't run everywhere that we need it to.
> > >>
> > >> Details please, or we aren't going to be able to even think about how to
> > >> solve this for you.
> > >>
> > >> BTW You can also do a xend migration to e.g. 4.2 (using the xend whichis
> > >> in 4.2) and the use 4.2's xl to do a localhost migrate or a second
> > >> remote migrate to another 4.2 system.
> > >>
> > >> xend's deprecation has been on the cards, and widely known, for several
> > >> releases now. It is time to quit stalling and start moving. I intend to
> > >> post a patch deleting it as soon as 4.4 is out the door.
> > >
> > > And I think I might have to lobby hard against removing it.
> 
> If by lobby you mean "step up to maintain" then please do.

I can surely do that, but I would prefer to have the issues fixed.

> 
> > > There are issues that are stopping us from using it:
> > >
> > >  - No status in xl list -l when only dom0 is present.
> 
> xl list -l produces a tonne of output here when only dom0 is present.
> 
> > >  - 'xl list -l' says 'Domain name must be specified' even though the '-l'
> > >    is for 'Output all VM details'
> 
> Not here it doesn't.
> 
> IIRC this was a bug in 4.1 or 4.2 timescales, which is now fixed.

Odd, I am running Xen 4.3. Hm, time to rebase.

> 
> > >  - xl list -l for PV guest has bug: itâs not formated S-expression text.
> 
> This is a feature not a bug. However you can request an sxp
> compatibility mode (I forget how, check the manpage). Note that this
> doesn't include new features, so you would be advised to make plans to
> switch to consuming the json variant.
> 
> > >  - No console in xl list -l, so can't get  tty console port.
> 
> That one should be easily fixable
> 
> > >  - xl uses SSH for migration. We need SSL daemon or socat like xend has.
> 
> You can provide any tool you like to run instead of ssh, including an
> ssl daemon/client or socat. See the manpage.

Right, except that the socat part does not work as the 'ssh' arguments
are encoded in the code. I am not saying that these are 'earth-shattering hard
to fix' it just that they should be done before Xend is gone.

> 
> > >
> > > Those should be fixed at some point :-) Problem is that other things
> > > keep on popping up on the radar and hence we end up using xend.
> > 
> > Uum, when were you going to report these?  A lot of us were under the
> > impression that xl behaved sufficiently like xend for anyone who
> > cared.
> > 
> > Maybe we should make an announcement (on blog, xen-users, xen-devel,
> > and xen-announce) that there has been a proposal to make 4.4 the last
> > release with xend, and so it's important to report all bugs / missing
> > features of xl so we can get them fixed by the 4.4 release?
> 
> Didn't we do this for 4.2 or 4.3? We didn't get much feedback.

No idea.
> 
> Ian.
> 

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