[ClusterLabs] Order constraint with a timeout?

[john tillman]

> On 29.03.2022 00:26, john tillman wrote:
>>> On Mon, 2022-03-28 at 14:03 -0400, john tillman wrote:
>>>> Greetings all,
>>>>
>>>> Is it possible to have an order constraint with a timeout?  I can't
>>>> find
>>>> one but perhaps I am using the wrong keywords in google.
>>>>
>>>> I have several Filesystem resource and one nfs service resource.  If
>>>> I
>>>> create 3 order constraints:
>>>>    pcs constraint order start fsRsc1 then start myNfsServiceRsc
>>>>    pcs constraint order start fsRsc2 then start myNfsServiceRsc
>>>>    pcs constraint order start fsRsc3 then start myNfsServiceRsc
>>>>
>>>> I would like to make sure that the nfs service will be started even
>>>> if one
>>>> of the Filesystem resources fails to start.  Is there a timeout that
>>>> could
>>>> be used?
>>>>
>>>> There is the "kind=Optional" parameter but that looks like it will
>>>> immediately start the second resource if the first failed to
>>>> start.  There
>>>> is no timeout option.
>>>>
>>>> Best regards,
>>>> -John
>>>>
>>>
>>> How do you envision the timeout working?
>>>
>>> You can add a timeout for the ordering itself using rules, where the
>>> ordering no longer applies after a certain date/time, but it doesn't
>>> sound like that's what you want.
>>> --
>>> Ken Gaillot <kgaillot at redhat.com>
>>>
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>>
>>
>> Thank you for the reply, Ken.
>>
>> I was hoping that I could give the Filesystem resource "X" seconds to
>> start.  If it failed to start after "X" then I would start the nfs
>> service
>> anyway.  So Those Filesystems that successfully started could be
>> accessed,
>> albeit with a bit of a delay before nfs is started.
>>
>
> What exactly "failed to start after "X"" means? Start operation is still
> running after "X" seconds? Then simply set timeout of start to "X".
> Start operation failed before "X" seconds? Then what is the point to
> wait additional time, how do you expect resource to become active if
> start operation already failed?
>



Andrei,

My understanding is that if one of the three Filesystem resources fails to
start then the nfsservice would fail to start, even if the other
Filesystem resources started successfully.  Am I wrong?

I suggested a timeout because I could not think of another cluster
mechanism that fit.  But I see your point.  The result is known and there
is no need to wait.  So a timeout is not what I need.

What can I use to start the nfs service only after all the Filesystem
resources have been given the chance to start?

-John



>> Basically, I want to start the nfs service regardless of whether any or
>> all of the Filesystem resources started.  But I want to give them all a
>> chance start before starting nfs.
>>
>> That said, it doesn't look like the rules suggestion you made is what I
>> need.  Any other ideas?
>>
>> Best Regards,
>> -John
>>
>>
>>
>>
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