[Libvir] [RFC] Linux-VServer support

[Daniel Veillard]

On Mon, Nov 05, 2007 at 01:17:11PM +0000, Daniel P. Berrange wrote:
> On Mon, Nov 05, 2007 at 05:33:02AM -0500, Daniel Veillard wrote:
> > On Thu, Nov 01, 2007 at 03:09:00AM +0100, Daniel Hokka Zakrisson wrote:
> > > After looking at the various drivers, this is what I propose:
> > > 
> > > <domain type='vserver' id='2000'>
> > >   <name>testvm</name>
> > >   <memory>500000</memory>
> > >   <scheduler fill_rate1='100' interval1='1000'>
> > >     <cpu id='0' fill_rate1='0'/>
> > >     <cpu id='1' fill_rate1='250' interval1='1000' idle_time='1' 
> > > fill_rate2='250' interval2='1000'/>
> > >   </scheduler>
> > >   <container>
> > >     <uts hostname='testvm' machine='i586'/>
> > >     <distribution method='debootstrap' release='etch'/>
> > >   </container>
> > >   <devices>
> > >     <disk type='path' device='path'>
> > >       <source path='/vservers/testvm'/>
> > >       <target path='/'/>
> > >     </disk>
> > >     <disk type='block' device='path'>
> > >       <source dev='/dev/hda4'/>
> > >       <target path='/var'/>
> > >     </disk>
> > >     <disk type='path' device='path'>
> > >       <source path='/home/testvm'/>
> > >       <target path='/home'/>
> > >     </disk>
> > >     <interface type='vserver'>
> > >       <ip family='IPv4' address='1.2.3.4' prefix='24' interface='eth0'/>
> > >     </interface>
> > >     <interface type='vserver'>
> > >       <ip family='IPv4' address='4.3.2.1' address2='4.3.2.200' 
> > > prefix='24' type='range'/>
> > >     </interface>
> > >     <interface type='vserver'>
> > >       <ip family='IPv6' address='dead:beef:dead:beef::1' prefix='64' 
> > > interface='eth0'/>
> > >     </interface>
> > >   </devices>
> > > </domain>
> > 
> >   That looks mostly fine to me except a few doubts about:
> >      - <scheduler> this is tuning and we need a global discussion about this
> >        we allowed something similar for OpenVZ but this need to be discussed
> >        more globally.
> >      - what are the ranges for the values of <container> elements and attributes
> >        <uts> seems to be OS metadata, we already have an <os> element in
> >        existing configs why not reuse that.
> >      - some of the <ip> args are new, i.e. have no equivalent in existing 
> >        config file uses:
> >         + family: that looks okay to me, is that mandatory ? Could that
> > 	  be guessed from one of the addresses given ?
> 
> Trivially - IPv4 is guarenteed to have a '.', and IPv6 is guarentted to have ':'.

  So maybe we can avoid that family selector

> > 	+ address2: what does that mean ? I understand one IP address being
> > 	  served but since there is not really a notion of physical interface
> > 	  why attach 2 address instead of defining 2 <interface> ?
> 
> I'd go for multiple <ip> tags inside the single <interface> tag, because this
> works in scenario where ythe 2nd address is a different family, or needs a
> different prefix 

  Agreed

> > 	+ prefix: could you explain what this means ? if it's a netmask
> > 	  let's use something like netmask="255.255.255.0" instead of 
> > 	  prefix="24"
> 
> Prefix is now preferred nomenculture for what used to be called netmask. The
> use of netmask is impratical in IPv6 world. You can trivially convert between
> the two in an app if you need the legacy netmask. 
> 
> Basically, prefix refers to the number of bits in the address which are
> significant. eg, the number of bits set to 1, in the netmask.

  okay, makes sense, I'm just old fashionned :-)
Let's use prefix then
> 
> I'd add that 'interface' should be in a separate <targe> element for
> consistency, and 'type=vserver' is probably redundant. We typically use just

  unless within a vserver domain other kind of interfaces are possible,
then yes that's redundant and can probably be avoided.

> type='ethernet' for a plain interface (ie one not bridged)
> 
>       <inteface type='ethernet'>
>          <ip address="1.2.3.4" prefix='24'/>
>          <target dev='eth0'/>
>       </interface>
> 
>       <inteface type='ethernet'>
>          <ip address="1.2.3.4" prefix='24'/>
>          <ip address="dead:beef:dead:beed::1" prefix='48'/>
>          <target dev='eth0'/>
>       </interface>

 okay

Daniel

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