[Libvir] [RFC] Add Container support to libvirt

[Dave Leskovec]

Thanks again for the feedback.  I've made the following additional 
recommended changes:
* Changed filesystem tag for consistency
* Changed network spec to match most recent OpenVZ format.  The latest 
OpenVZ format I could find was here:
https://www.redhat.com/archives/libvir-list/2007-August/msg00209.html
Shuveb - does this line up with what OpenVZ is now using?
* Removed cpushare and memory tuning parameters

Updated format:
<domain type='linuxcontainer'>
   <name>Container123</name>
   <uuid>8dfd44b31e76d8d335150a2d98211ea0</uuid>
   <container>
       <filesystem type="mount">
          <source dir="/home/user/lxc_files/etc/"/>
          <target dir="/etc/"/>
       </filesystem>
       <filesystem type="mount">
          <source dir="/home/user/lxc_files/var/"/>
          <target dir="/var/"/>
       </filesystem>
       <application>/usr/sbin/container_init</application>
       <network>
           <ipaddress>192.168.1.110</ipaddress>
           <hostname>browndog</hostname>
           <gateway>192.168.1.1</gateway>
           <nameserver>192.168.1.1</nameserver>
           <netmask>255.255.255.0</netmask>
       </network>
   </container>
   <devices>
       <console tty='/dev/pts/4'/>
   </devices>
</domain>

As always, all comments and questions are welcome.

Daniel P. Berrange wrote:
> On Tue, Jan 15, 2008 at 12:26:43AM -0800, Dave Leskovec wrote:
>   
>> Greetings,
>>
>> Following up on the XML format for the Linux Container support I 
>> proposed...  I've made the following recommended changes:
>> * Changed mount tags
>> * Changed nameserver tag to be consistent with gateway
>> * Moved cpushare and memory tags outside container tag
>>
>> This is the updated format:
>> <domain type='linuxcontainer'>
>>   <name>Container123</name>
>>   <uuid>8dfd44b31e76d8d335150a2d98211ea0</uuid>
>>   <container>
>>       <filesystem>
>>           <mount>
>>               <source dir="/home/user/lxc_files/etc/"/>
>>               <target dir="/etc/"/>
>>           </mount>
>>           <mount>
>>               <source dir="/home/user/lxc_files/var/"/>
>>               <target dir="/var/"/>
>>           </mount>
>>       </filesystem>
>>     
>
> Comparing this to the Linux-VServer XML that Daniel posted, you're both
> pretty much representing the same concepts so we need to make a decision
> about which format to use for  filesystem mounts.
>
> OpenVZ also provides a /domain/container/filesystem tag, though it
> uses a concept of filesystem templates auto-cloned per container
> rather than explicit mounts. I think I'd like to see
>
>        <filesystem type="mount">
>                <source dir="/home/user/lxc_files/etc/"/>
>                <target dir="/etc/"/>
>        </filesystem>
>
> For the existing OpenVZ XML, we can augment their <filesystem> tag with
> an attribute  type="template".
>
>   
>>       <application>/usr/sbin/container_init</application>
>>       <network hostname='browndog'>
>>           <ip address="192.168.1.110" netmask="255.255.255.0"/>
>>               <gateway address="192.168.1.1"/>
>>               <nameserver address="192.168.1.1"/nameserver>
>>           </ip>
>>       </network>
>>     
>
> Again this is pretty similar to needs of VServer / OpenVZ. In the existing
> OpenVZ XML, the gateway and nameserver tags are immediately within the
> <network> tag, rather than nested inside the <ip> tag. Aside from that it
> looks to be a consistent set of information.
>
>   
>>   </container>
>>   <cpushare>40</cpushare>
>>     
>
> As Daniel points out, we've thus far explicitly excluded tuning info from
> the XML. Not that I have any suggestion on where else to put it at this
> time. This is a minor thing though, easily implemented once we come to a
> decision.
>
>   
>>   <memory>65536</memory>
>>   <devices>
>>       <console tty='/dev/pts/4'/>
>>   </devices>
>> </domain>
>>
>> Does this look ok now?  All comments and questions are welcome.
>>     
>
> Pretty close.
>
> Dan.
>   
-- 

Best Regards,
Dave Leskovec
IBM Linux Technology Center
Open Virtualization