[Pacemaker] Advisory ordering on clones not working?

[Vladislav Bogdanov]

21.02.2012 02:40, Andrew Beekhof wrote:
> On Mon, Feb 20, 2012 at 11:49 PM, Vladislav Bogdanov
> <bubble at hoster-ok.com> wrote:
>> 20.02.2012 14:36, Andrew Beekhof wrote:
>>> On Mon, Feb 20, 2012 at 10:26 PM, Adrian Fita <adrian.fita at gmail.com> wrote:
>>>> Thanks, I figured it out by now. But the real problem I'm facing is
>>>> explained in http://oss.clusterlabs.org/pipermail/pacemaker/2012-February/013124.html
>>>> . Please also take a look there. This advisory thing was me trying to
>>>> solve the problem described in that message.
>>>
>>> Ok, I see that thread.  I'll get to that one soon.
>>
>> I now look at the similar case (advisory ordering doesn't work).
>>
>> I hope I can add some pointers on what exactly happens.
>>
>> Imagine you have two advisory-ordered resources each also depend
>> (colocated and mandatory ordered) on some other resource (f.e.
>> filesystem on drbd device Master state).
>> I now play with lustre filesystem. It consists of several parts:
>> * MGS (one per cluster, cluster can consist of several lustre filesystems)
>> * MDT (one per filesystem)
>> * OST (many per filesystem)
>> It is very important for lustre to operate properly that MDT is started
>> after MGS and OSTs started after MDT.
> 
> The you must not use advisory constraints for this sequence.

Heh, but then I will be unable to move filesystem parts between drbd
replicas for failover... Advisory ordering allows me to move MGS or MDT
to another replica without restarting all the OSTs.

Need to think again about making them migratable...

> 
>>
>> In my case I have MDT configured to start after MGS (advisory) and each
>> OST to start after MDT. Each of lustre parts is resided on a drbd device
>> (stacked one, so there is one more drbd device under it).
>>
>> What I see after transition from stop-all-resources="true" to "false" is
>> that some OSTs (which are located on nodes different from where MDT is)
>> are started before MDT. I see that advisory ordering is not honored when
>> dependencies of "then" resource are satisfied before ones of "first"
>> resource.
> 
> So /both/ sides of the constraint are starting or stopping but the PE
> isn't enforcing the ordering?

At one moment LogActions prints that they all are about to start.
Then deps for two "then" resources are satisfied and they are actually
started while "first" resource is not.

> 
> 
>> hb_report?
>>
>> Best,
>> Vladislav
>>
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