Re: [Xen-devel] [OSSTEST Nested PATCH v8 3/7] Edit some APIs in TestSupport.pm for nested test

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Tue, 2015-04-21 at 15:30 +0100, Ian Jackson wrote:
> Ian Campbell writes ("Re: [OSSTEST Nested PATCH v8 3/7] Edit some APIs in 
> TestSupport.pm for nested test"):
> > On Tue, 2015-04-21 at 14:28 +0100, Ian Jackson wrote:
> > > I'm only objecting to the involvement of the host property machinery.
> > 
> > I'm afraid I'm not 100% sure I understand, but do you just mean that
> > longtao should assign to $ho->{Ip} directly within selecthost instead of
> > using $setprop to set the IpAddr hostprop and therefore indirectly
> > ->{Ip}?
> 
> Yes.
> 
> > IOW the existing code in selecthost which looks up the IpAddr host prop
> > into $ho->{IpStatic} and then into $ho->{Ip} should prefer the runvar to
> > the host db if it is set?
> 
> Yes.

Good. Longtao, do you understand what is needed here?

> > BTW, what is the difference between ->{Ip} and ->{IpStatic} and should
> > the runvar be reflected in both or just in ->{Ip}?
> 
> AFAICT the only difference is that only IpStatic is used for expanding
> `ipaddr' and `ipaddrhex' in the patterns for dhcp pxe configurations.
> 
> There is an incipient problem here: our existing setup does not
> require that osstest has complete control of the pxe config file for
> every host on the network.  And indeed the Citrix (Cambridge) instance
> lacks such control.
> 
> Instead there are some symlinks etc.  The mg-hosts mkpxedir subcommand
> arranges to delegate the DHCP from root to the osstest user (and
> group), by making an appropriate subdirectory with the right
> permissions, and a suitable symlink.
> 
> It's not quite clear to me how this should work for nested HVM hosts.

I think this is OK with the current design because the nested HVM host
is not PXE booted, it is installed as a guest but preseeded to look a
lot like a host (quite a lot of sharing in the preseed creation) and
then tailored into a more host-like thing by things like this IP addr
runvar.

So I think from what you are saying that the ->{Ip} and ->{IpStatic}
distinction here is correct and a host which is really a guest should
not have nor use ->{IpStatic} (we want e.g. attempts to create a pxe dir
to fail).

Longtao, the conclusion is that the runvar should only appear in ->{Ip}.

->{IpStatic} should be left untouched (i.e. not initialised).

Ian.


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