Re: [Xen-users] Xen 4.2.2 /etc/init.d/xendomains save and restore of domains does not work

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2013-07-03 at 00:31 +0200, Andreas Greve wrote:

> My future wish is to start and stop domains in an fixed order because 
> they depends on each other in some way. If the starting logic is hard 
> coded in xl I have no chance to implement such things for myself.

FWIW I think this sounds like useful functionality for general use, so
whichever way you implement it it'd be great if it could go upstream
too.

> I would prefer at tool perhaps xl I can give simple questions and get 
> short shell purchasable answers

Yes, that was one of the ideas I proposed in
<1372758282.27768.57.camel@xxxxxxxxxxxxxxxxxxxxxx>

> examples
> 
> xl query <domid>|<domname> <attribute> and the answer is a single value 
> or fails if domid is not running
> 
> xl query gnomedag domid  ---> produce     1 or ''
> 
> xl queryall <attribute>  returns a list <domainame> <value>\n<domainame> 
> value ....
> 
> perhaps getattribute is a better token for query
> 
> As a replacement for the create --dryrun ....
> xl queryconf <configfile> <attribute> and the answer is a single value
> 
> An other nice to have  will be to query for an attribute list with the 
> answer <value1> <value2> <value3>
> respectively <domainame> <value1> <value2> ...\n<domainame> <value1> 
> <value2> ...
> 
> The attribute should not be limited to configuration attributes. I wish 
> to query dynamic values like domain state, cpu usage, disk usage and 
> other things like that too.
> 
> Please excuse if the above is jolty worded.

It all sounds plausible. We've just opened the 4.4 development branch so
now is as good a time as any to start working on these things.

Ian.

> 
> 
> Andreas
> 
> On 07/02/13 12:20, Ian Murray wrote:
> >
> >
> >
> > ----- Original Message -----
> >> From: Ian Campbell<Ian.Campbell@xxxxxxxxxx>
> >> To: Ian Murray<murrayie@xxxxxxxxxxx>
> >> Cc: "greve-ml@xxxxxxxxxx"<greve-ml@xxxxxxxxxx>; 
> >> xen-users<xen-users@xxxxxxxxxxxxx>; 
> >> "andreas.greve@xxxxxxxxxx"<andreas.greve@xxxxxxxxxx>
> >> Sent: Tuesday, 2 July 2013, 10:44
> >> Subject: Re: [Xen-users] Xen 4.2.2 /etc/init.d/xendomains save and restore
> >   of domains does not work
> >> On Tue, 2013-07-02 at 10:40 +0100, Ian Murray wrote:
> >>>   >  Even better would be to just do away with this madness of parsing 
> >>> JSON
> >>>   >  or SXP in shell (keeping it only for xm compatibility) and add proper
> >> xl
> >>>   >  commands to save and restore all domains to/from a given directory.
> >>>
> >>>   Xendomains does quite a bit of high level stuff.... it's a
> >>>   "convenience" script IMHO which not only deals with suspending
> >> and
> >>>   restoring but also starting the auto domains and dealing with things
> >>>   that appear in both (i.e. the skipping of auto start stuff that has
> >>>   just been restored). From a design point of view, is it the right
> >>>   thing to do to move all that logic in xl? ... or keep it in a seperate
> >>>   tool (but definitely re-written.)
> >> Probably one to RFC on the devel list before committing lots of code
> >> too, but I think its the sort of thing we could accept.
> > I think a discussion about what xendomains is supposed to do (especially 
> > dealing with the more obscure stuff like zombies and system requests) would 
> > be a decent place to start I think that would shape the technical response.
> >
> >> Doing it in xl would be convenient, but a separate tool might also be
> >> workable. The main point is "don't parse JSON in shell"!
> >>
> > I think everyone would agree with that.
> >
> >> You could also consider implementing a more shell friendly output mode
> >> though, which just produces FOO-separated lines of text with the name
> >> and domid in them...
> > I think state would be needed as well.
> >
> >
> >> Ian.
> >>
> > I
> >
> 



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