[Engine-devel] Change in ovirt-engine[master]: core: enable to decrease DC compatibility...

[Itamar Heim]

On 03/23/2014 01:13 PM, Livnat Peer wrote:
> On 03/23/2014 01:10 PM, Itamar Heim wrote:
>> On 03/23/2014 12:25 PM, Livnat Peer wrote:
>>> On 03/23/2014 12:13 PM, Eli Mesika wrote:
>>>>
>>>> So, as far a I understand for resolving this bug the following is OK :
>>>>
>>>> Block downgrading if there are Hosts or Networks (other than the
>>>> default management network) or SD in the DC when downgrading.
>>>>
>>>
>>>
>>> Why does having hosts should prevent us from downgrading the DC level?
>>
>> tomorrow you may have hosts which won't support an older cluster.
>
> Host are associated with a cluster, how can downgrading of DC level
> impact the existing hosts? DC downgrade does not downgrade the clusters
> level.
>

well, you are kind of explaining why this can't happen...
a DC can only be upgraded if all Clusters have already been upgraded.
hence a DC can only be downgraded if it has no clusters, hence no hosts.
(because to downgrade the DC, the clusters would have to be downgraded 
first, and you can't have a cluster lower than the DC...)