[OCF] Adding "reload" to the OCF specification

[Alan Robertson]

Many LSB init scripts implement a 'reload' action which permits them to 
reread their configurations without interrupting service.

By design, OCF spec is upwards-compatible with the LSB.

I think it would be good to specifically add the reload operation to the 
OCF spec.

Saying something like this:
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The reload operation is an optional operation which can be supported by 
OCF resource agents.  This operation will cause the resource to examine 
its parameters and its configuration files, and continue running these 
new configuration values, without interrupting service in a way which is 
visible to resources which depend on it.

If an OCF resource agent wishes to support the reload operation, it is 
required to list it in the <operations> section of the metadata given by 
the meta-data operation.

Even though a resource supports a reload operation, a conforming cluster 
manager need not make use of it.  Of course, if it does, then service 
updates can be made with fewer service interruptions, so this is likely 
to be seen as a desirable feature.
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And as to whether there are resource agents which could make use of this 
feature - the answer is yes.  I have a customer who would like such a 
capability today.  At the moment, they go far out of their way to work 
around not having it.

As written, this is optional for both resource agents and cluster 
managers, and it seems like a reasonable addition to the OCF spec.

My guess is that this would be an easy addition for many cluster 
managers to support.  Of course, nothing is impossible to he who doesn't 
have to do it.

-- 
     Alan Robertson <alanr at unix.sh>

"Openness is the foundation and preservative of friendship...  Let me 
claim from you at all times your undisguised opinions." - William 
Wilberforce