[ovirt-devel] vdsm disabling logical volumes

[Itamar Heim]

On 05/14/2014 03:02 AM, Jiri Moskovcak wrote:
> On 05/14/2014 02:57 AM, Itamar Heim wrote:
>> On 05/13/2014 03:16 AM, Jiri Moskovcak wrote:
>>> On 05/12/2014 05:27 PM, Dan Kenigsberg wrote:
>>>> On Mon, May 12, 2014 at 02:04:05PM +0200, Jiri Moskovcak wrote:
>>>>
>>>>>>>> Jiri, could you describe why you keep your LV active, but not open?
>>>>>>>>
>>>>>>>
>>>>>>> - the setup flow goes approximately like this:
>>>>>>>
>>>>>>> 1. create the LVs for the hosted-engine
>>>>>>> 2. install the engine into the VM
>>>>>>> 3. add the host to the engine
>>>>>>>    - this causes re-deploy of vdsm and deactivating the LVs
>>>>>>> 4. start the ha-agent and ha-broker services which uses the LVs
>>>>>>>
>>>>>>> - I guess we could move the creation of the LVs after the vdsm is
>>>>>>> re-deployed, just before the HE services are started, but it won't
>>>>>>> fix the problem if the vdsm is restarted
>>>>>>
>>>>>> It's not going to solve our design problem, but can the users of
>>>>>> that LV
>>>>>> activate it just before they open it? This way there's only a small
>>>>>> window where vdsm can crash, restart, and deactivate the LV.
>>>>>>
>>>>>
>>>>> - no, it runs as vdsm user and as it seems only root can activate LVs
>>>>> and
>>>>> during the startup when it still has the root privs, it doesn't know
>>>>> anything about the storage, the storage is connected on a client
>>>>> request
>>>>> when it already doesn't have root privs
>>>>
>>>> Vdsm uses "sudo" for these purposes.
>>>
>>> - that would solve the problem with privs, but I would really like to
>>> avoid the situation where the vdsm disables the LVs as there is no
>>> reason for disabling it as there can be situation where vdsm is down and
>>> the VM with the engine is still running ok
>>>
>>>>
>>>>> - we could use vdsm to activate the LV if it provides API which
>>>>> allows that
>>>>
>>>> There's the undocumented prepareImage(), but please do not use it
>>>> before
>>>> an ack by the storage team.
>>>>
>>>
>>> - sure, I'm working on it with Nir now, I won't do anything without the
>>> storage team approval ;)
>>>
>>>> Dan.
>>>>
>>>
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>>
>> I'm missing something here - why doesn't VDSM knows about this LV? its a
>> VM started by VDSM?
>
> - these LVs are created by hosted-engine-setup and are not connected
> with the VM

for the metadata/config/etc.?