[ClusterLabs] Q: utilization, stickiness and resource placement

[Ulrich Windl]

Hi!

I have a question about utilization-based resource placement (specifically: placement-strategy=balanced):
Assume you have two resource capacities (say A and B) on each node, and each resource also has a utilization parameter for both.
Both nodes have enough capacity for a resource to be started.
Consider these cases for resource R:
1) R needs A = B
2) R needs A > B
3) R needs A < B

Maybe consider these cases for each node:
a) A = B
b) A > B
c) A < B

Where would the resources be placed?
(Obviously A and B are independent, so you can't say "How many A is worth one B" (or vice versa)

Then, given some placement, assume that node capacity for A or B increases on a node.
How large has the stickiness parameter for the resource have to be to prevent resource migration?

Are there any tools to help understanding?

Note: For placement-strategy=utilization it's easier: As long as there is sufficient capacity, distribute the resources on the node that has least number of resources.

Regards,
Ulrich