[Linux-ha-dev] Uniquness OCF Parameters

[Florian Haas]

On 2011-06-15 15:50, Alan Robertson wrote:
> On 06/14/2011 06:03 AM, Florian Haas wrote:
>> On 2011-06-14 13:08, Dejan Muhamedagic wrote:
>>> Hi Alan,
>>>
>>> On Mon, Jun 13, 2011 at 10:32:02AM -0600, Alan Robertson wrote:
>>>> On 06/13/2011 04:12 AM, Simon Talbot wrote:
>>>>> A couple of observations (I am sure there are more) on the uniqueness flag for OCF script parameters:
>>>>>
>>>>> Would it be wise for the for the index parameter of the SFEX ocf script to have its unique flag set to 1 so that the crm tool (and others) would warn if one inadvertantly tried to create two SFEX resource primitives with the same index?
>>>>>
>>>>> Also, an example of the opposite, the Stonith/IPMI script, has parameters such as interface, username and password with their unique flags set to 1, causing erroneous warnings if you use the same interface, username or password for multiple IPMI stonith primitives, which of course if often the case in large clusters?
>>>>>
>>>> When we designed it, we intended that Unique applies to the complete set
>>>> of parameters - not to individual parameters.  It's like a multi-part
>>>> unique key.  It takes all 3 to create a unique instance (for the example
>>>> you gave).
>>> That makes sense.
>> Does it really? Then what would be the point of having some params that
>> are unique, and some that are not? Or would the tuple of _all_
>> parameters marked as unique be considered unique?
>>
> I don't know what you think I said, but A multi-part key to a database 
> is a tuple which consists of all marked parameters.  You just said what 
> I said in a different way.
> 
> So we agree.

Jfyi, I was asking a question, not stating an opinion. Hence the use of
a question mark.

So then, if the uniqueness should be enforced for a "unique key" that is
comprised of _all_ the parameters marked unique in a parameter set, then
what would be the correct way to express required uniqueness of
_individual_ parameters?

In other words, if I have foo and bar marked unique, then one resource
with foo=1 and bar=2, and another with foo=1, bar=3 does not violate the
uniqueness constraint. What if I want both foo and bar to be unique in
and of themselves, so any duplicate use of foo=1 should be treated as a
uniqueness violation?

Florian

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