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

[Livnat Peer]

On 03/20/2014 09:20 PM, Moti Asayag wrote:
> ----- Original Message -----
>> From: "Moti Asayag" <masayag at redhat.com>
>> To: "Livnat Peer" <lpeer at redhat.com>
>> Cc: "Itamar Heim" <iheim at redhat.com>, engine-devel at ovirt.org
>> Sent: Wednesday, March 12, 2014 10:44:07 PM
>> Subject: Re: [Engine-devel] Change in ovirt-engine[master]: core: enable to decrease DC compatibility...
>>
>>
>>
>> ----- Original Message -----
>>> From: "Livnat Peer" <lpeer at redhat.com>
>>> To: "Moti Asayag" <masayag at redhat.com>
>>> Cc: "Itamar Heim" <iheim at redhat.com>, engine-devel at ovirt.org
>>> Sent: Wednesday, March 12, 2014 10:33:45 PM
>>> Subject: Re: [Engine-devel] Change in ovirt-engine[master]: core: enable to
>>> decrease DC compatibility...
>>>
>>> On 03/12/2014 10:20 PM, Moti Asayag wrote:
>>>>
>>>>
>>>> ----- Original Message -----
>>>>> From: "Livnat Peer" <lpeer at redhat.com>
>>>>> To: "Itamar Heim" <iheim at redhat.com>, engine-devel at ovirt.org
>>>>> Sent: Wednesday, March 12, 2014 12:42:44 PM
>>>>> Subject: Re: [Engine-devel] Change in ovirt-engine[master]: core: enable
>>>>> to	decrease DC compatibility...
>>>>>
>>>>> On 03/12/2014 11:59 AM, Itamar Heim wrote:
>>>>>> On 03/12/2014 12:26 AM, emesika at redhat.com wrote:
>>>>>>> Eli Mesika has submitted this change and it was merged.
>>>>>>>
>>>>>>> Change subject: core: enable to decrease DC compatibility...
>>>>>>> ......................................................................
>>>>>>>
>>>>>>>
>>>>>>> core: enable to decrease DC compatibility...
>>>>>>>
>>>>>>> enable to decrease DC compatibility version if DC has no clusters
>>>>>>>
>>>>>>> This patch enables to decrease the DC compatibility version if DC has
>>>>>>> no
>>>>>>> clusters.
>>>>>>
>>>>>> Eli - just saw this. I'm pretty sure it would be *bad* to downgrade a
>>>>>> DC
>>>>>> version if it has storage domains as well. not sure if this is checked
>>>>>> already or not.
>>>>>>
>>>>>> may also be an issue with some logical network features.
>>>>>>
>>>>>
>>>>> Most of the network features are driven from cluster level, we enable
>>>>> using the features on all DC level (actually >=3.1) but actually enable
>>>>> /disable the feature when attaching the network to a cluster.
>>>>>
>>>>> So from network perspective I think it should be fine to downgrade the
>>>>> DC level even if there are networks in the DC (at least now this could
>>>>> change in future versions).
>>>>>
>>>>
>>>> Actually we block adding or updating networks if the feature is not
>>>> supported
>>>> on the network's DC level, for example: STP, Jumbo frames and non-vm
>>>> network.
>>>>
>>>
>>> From which DC level we support STP?  Jumbo frames? non-vm network? isn't
>>> all of them supported in >=3.1 ?
>>>
>>
>> Yes, mainly the problem with downgrading a DC to 3.0.
>>
> 
> I had a discussion with Mike (cc'ed) about several possible solutions
> for the networks compatibility within the data-center.
> 
> The first proposed solution would utilize the NetworkUpdateValidator,
> a validation utility that verifies the compatibility of a network
> to the data-center. This solution preserves the same behaviour as today,
> that the features of network-level are dictated by the DC version. No
> need to reimplement any logic in the decrease DC version flow, just use
> an existing one to be applied for any network within the DC.
> 
> The second solution suggests we allow any settings of a network, and 
> compatibility enforcement is done on attaching the network to the clusters.
> This modifies the existing behaviour and expands the capabilities of the
> engine to support advanced network feature in advanced cluster within an
> old data center (i.e. cluster 3.4 in 3.0 data-center could and probably
> should use non-vm network, jumbo-frames and more).
> This option requires more work in add/update network and attach network to cluster
> flows, both on the backend and UI. Specifically since by default a new network
> created in a DC is being attached to all of the clusters.
> Perhaps the second option deserves to be treated as RFE and not as a bug fix.
> 
> Thoughts ?
> 

The second approach you suggested is equivalent to creating networks in
cluster level vs. DC level, which is used today.

We should consider that for 4.0 and think on the pros and cons of doing so.

In general for this specific discussion I think a simple block on DC
downgrade should be enough.

> Moti
>  
>>>> Therefore if the management network was configured with any of those
>>>> feature,
>>>> there is a need to either block the action or to 'initialize' the network
>>>> to
>>>> the default settings (as new network being added).
>>>>
>>>>> In general I believe the use case for this patch is mostly for empty DCs
>>>>> so for simplicity we should block it if there are networks or SD in the
>>>>> DC when downgrading.
>>>>>
>>>>> Livnat
>>>>>
>>>>>
>>>>>>>
>>>>>>> Change-Id: I73284f641b7f80b380b39efbbd7b4566f55119b6
>>>>>>> Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1057029
>>>>>>> Signed-off-by: Eli Mesika <emesika at redhat.com>
>>>>>>> ---
>>>>>>> M
>>>>>>> backend/manager/modules/bll/src/main/java/org/ovirt/engine/core/bll/storage/UpdateStoragePoolCommand.java
>>>>>>>
>>>>>>> 1 file changed, 5 insertions(+), 2 deletions(-)
>>>>>>>
>>>>>>> Approvals:
>>>>>>>    Eli Mesika: Verified
>>>>>>>    Ravi Nori: Looks good to me, but someone else must approve
>>>>>>>    Yair Zaslavsky: Looks good to me, approved
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Engine-devel mailing list
>>>>> Engine-devel at ovirt.org
>>>>> http://lists.ovirt.org/mailman/listinfo/engine-devel
>>>>>
>>>
>>>
>>
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