[vdsm] Per device custom properties

[Itamar Heim]

On 03/20/2013 09:43 AM, Yair Zaslavsky wrote:
>
>
> ----- Original Message -----
>> From: "Itzik Brown" <ItzikB at mellanox.com>
>> To: "Dan Kenigsberg" <danken at redhat.com>, "Assaf Muller" <amuller at redhat.com>, "Yair Zaslavsky"
>> <yzaslavs at redhat.com>, "Eldan Hildesheim" <ehildesh at redhat.com>, izikb at mellanox.com
>> Cc: vdsm-devel at lists.fedorahosted.org, arch at ovirt.org, "Irena Berezovsky" <irenab at mellanox.com>
>> Sent: Wednesday, March 20, 2013 9:17:08 AM
>> Subject: RE: [vdsm] Per device custom properties
>>
>> Hi,
>>
>> I think that this feature is a good start for enabling vendor
>> specific hints which apply to VM Network/Disk devices.
>> There is a need to add migration  hooks to the list.
>>
>> Itzik
>>
>> -----Original Message-----
>> From: Dan Kenigsberg [mailto:danken at redhat.com]
>> Sent: יום ג 19 מרץ 2013 17:12
>> To: Assaf Muller; Yair Zaslavsky; Eldan Hildesheim;
>> izikb at mellanox.com
>> Cc: vdsm-devel at lists.fedorahosted.org; arch at ovirt.org
>> Subject: Re: [vdsm] Per device custom properties
>>
>> adding arch at ovirt, as this feature is cross sub-project
>>
>> On Sun, Mar 17, 2013 at 09:50:20AM -0400, Assaf Muller wrote:
>>> Hi all,
>>>
>>> Right now we have the ability to define VM-wide properties that may
>>> be
>>> used by hooks.
>>> It is time we have the same functionality on a device basis:
>>> http://www.ovirt.org/Features/Device_Custom_Properties
>>
>> This feature page needs some love and attention.
>>
>> * I received a private communication about the suggested GUI: there
>>    should not be an independent vNIC action called "custom Properties"
>>    -
>>    the dialog for editing per-vNIC custom properties should be part of
>>    defining a new vNIC or editting an existing one. I believe Eldan
>>    (our
>>    GUI designer) concurs.
>>
>> * http://www.ovirt.org/Features/Device_Custom_Properties#Engine is
>>    rather lacking concrete details. Yair, could you improve it, as
>>    well
>>    as the completely empty REST section?
>
> I would prefer Michael Pasternak handles REST-API.
> Regarding the rest of the engine side- I'll assist.
> I would consult with Eli on this, as he was/is the feature owner of VM devices.
>
>>
>>>
>>> For example: If the VM has 2 disks called disk1 and disk2, and two
>>> NICs called nic1 and nic2, and the admin (From the engine) added a
>>> custom property qos: 0.5 for nic1 and a custom property defrag:
>>> None
>>> for disk2. When the VM is started we'll run a hook for nic1 with
>>> its
>>> XML and qos: 0.5 added as an environment variable, and a hook for
>>> disk2 with its XML and defrag: None.
>>>
>>> When a device is hot plugged and it has custom properties we'll run
>>> that hook as well.
>>>
>>> Implementation-wise, hot plug/unplug for disks and NICs is dead
>>> simple
>>> - vmCreate is more problematic:
>>> If the user set a custom property called 'qos: 0.8' for nic3, I'd
>>> want
>>> it exposed as an environment variable called 'qos' for hot plug nic
>>> hooks, but for vmCreate I'd like to prefix the nic's alias.
>>>   However,
>>> when vmCreate is called we don't have the aliases for NICs and
>>> disks.
>>>
>>> The proposed solution is to create a new hook point called
>>> something
>>> like: 'before_device_creation' that will be called before vmCreate.
>>> We'll then call that hook specifically for devices that contains
>>> custom properties, as described in the second paragraph of this
>>> mail.
>>>
>>>
>>> I would love to hear smarter ideas before I move forward. Thanks!
>>
>> I find it quite intuitive, but I'd rather hear if it feats Izik's use
>> case.
>>
>> Dan.
>>
> _______________________________________________
> vdsm-devel mailing list
> vdsm-devel at lists.fedorahosted.org
> https://lists.fedorahosted.org/mailman/listinfo/vdsm-devel
>

one point for consideration is we may want to make custom properties 
"managed entities" in the future, rather than 'blobs'. this will 
especially be important to allow managing permissions on them.