[Engine-devel] Cluster default with empty processor name with PPC64 support

[Roy Golan]

On 09/02/2013 03:35 PM, Leonardo Bianconi wrote:
>>> From: Roy Golan [mailto:rgolan at redhat.com]
>>> Sent: domingo, 1 de setembro de 2013 05:07
>>> To: Leonardo Bianconi
>>> Cc:engine-devel at ovirt.org
>>> Subject: Re: [Engine-devel] Cluster default with empty processor name with PPC64 support
>>>
>>> On 08/30/2013 10:51 PM, Leonardo Bianconi wrote:
>>> Hi everyone!
>>>   
>>> During the development of PPC64 support in the engine, we faced some UX issues regarding the default Cluster (that Cluster with empty processor name).
>>>   
>>> Currently, oVirt engine allows the default Cluster to contain empty processor name, and the administrator can add VMs and/or Templates to it. The processor name can be assigned later, editing the cluster or assigning a valid host to it.
>>>   
>>> During the implementation of PPC64 support on the engine, the field "architecture" was added to Clusters, VMs and Templates entities.
>>>   
>>> So we have the following questions regarding how the UI should behave:
>>>   
>>> - Shall we keep allowing the administrator to assign VMs and Templates to the Cluster with no processor name or assigned architecture ?
>>>               -> If we have an "yes" for the question above:
>>>               -- We will have to assign the architecture to the Cluster based on the OS of the first assigned VM, and  the processor name could be defined the same way as currently ... editing the Cluster or assigning a compatible Host to it.
>>>                               -- The VM creation popup will have to be able to indicate the architecture of each OS ... some OSes have the same name, and it may get ambiguous since the Cluster architecture is still undefined at that point (before the first VM get already created).
>>>   
>>> Thanks!
>>> Regards.
>>> Leonardo Bianconi
>>>
>> To add VMs you anyway need a running host in the cluster which means the cpu name and the architecture would be the host's.
>> So we can keep the cluster attributes - "cpu name" and "arch" consistent and allow them to be empty on creation.
>>
>>
> Hi Roy!
>
> There is a way to add VMs in a cluster with no hosts running. Steps to reproduce:
> - Initialize the oVirt engine with a new data base
> - Create a new Cluster (I will call it of newCluster) in the Data Center Default
> - Add a host in the newCluster
> - Add a Storage
> - Create a VM in the Cluster Default
> Result: The system allows a VM in a cluster with no Hosts running in it.
>
> Is it a bug or a system functionality? If it's a functionality, the issue above can happen.
Just to clear this one - its a functional thing. its a bit confusing but 
not too complicated:

Storage and all its related actions/entities are related to the Data 
Center (aka, code-wise storage pool). Its possible to
create a VM once the DC is up, without a cluster i.e also provision 
disks to it and so on.

Cluster is know as the "migration domain" wrt VMs. so CPU arch stuff, 
network config (also has a DC part though) and various other vars, must 
be homogeneous in order
for VMs to migrate between hosts. So cluster isn't really fully 
configured till it has at least 1 host up.

hope this make things clearer


> Thanks!!
> Regards.
> Leonardo Bianconi
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