Allow user to specify CPU overcommit setting

Registered by Dmitriy Novakovskiy on 2014-06-24

Context:

While preparing for cloud deployment OpenStack users usually elaborate the decision on CPU overcommit ratio to be used. A number of factors impact this decision - type of hypervisor to be used, expected CPU utilization by VMs, VM density, etc.

At the moment (Fuel 5.0) CPU overcommit setting is hardcoded in Fuel. Adjusting it as a post-install/ops step is not good from UX perspective (it's an important decision, UI should prompt user to make it) and not good for configuration consistency/reliability (see discussion in https://lists.launchpad.net/fuel-dev/msg01211.html)

Feature proposal:

- Expose "CPU overcommitment ratio" setting in Wizard on Hypervisor selection screen
- To simplify things initially - implement the setting as a drop-down list, with 2 options:
-- No CPU overcommitment (1:1)
-- Light CPU overcommitment (3:1)
-- Heavy CPU overcommitment (6:1) --- default setting in BOM calculator

Blueprint information

Status:
Not started
Approver:
None
Priority:
Medium
Drafter:
Dmitriy Novakovskiy
Direction:
Needs approval
Assignee:
None
Definition:
New
Series goal:
Accepted for future
Implementation:
Not started
Milestone target:
milestone icon next

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[Dmitry Borodaenko 2014-10-10] Removed from 6.0 milestone, re-targeted for future.

[Ian Unruh 2015-03-17] This should probably be expanded to cover memory overcommit as well. This is especially a problem when Ceph is colocated onto the compute nodes (as some customers have done). Other customers have run into OOM problems with just standalone compute nodes. I also believe it's as important (or more important) of a decision as selecting a CPU overcommit value, as DN suggested.

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Work Items

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