[Pacemaker] crmsh: New syntax for location constraints, suggestions / comments

[Kristoffer Grönlund]

On Fri, 13 Dec 2013 10:55:32 +0100
Michael Schwartzkopff <ms at sys4.de> wrote:

> Order for colocations and order constraints: Please don't do it.
> Everybody got use to the ordering as it is now. It also makes sense.
> Please remember the irritations we had moving from heartbeat 2.0
> (with XML, shudder) to the new pacemaker/crm syntax and constraint
> orders. I don't want to have that again.

This worries me as well, however the current syntax for constraints is
confusing and error-prone. It would be great to be able to do something
to make this easier to use, but exactly what it would be is hard to
say. Making a change that would silently invert the functionality of
existing configurations is, I agree, not a good idea. However, maybe it
would be acceptable if a "version: 2" header is required in the
document to enable the new syntax?

Yet another option is to come up with some entirely new construct to
supplement colocation and order which does what I think most people
intuitively expects by default, which is enforces both colocation and
ordering, so that 'foo depends on bar' means foo will start after bar,
and only where bar is running.

-- 
// Kristoffer Grönlund
// kgronlund at suse.com
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