Unable to set custom overcommit ratio

[Andrey Danin]

In 5.0 (and 4.1.1 afterward) we implemented custom overcommit ratios for Nova Scheduler in Puppet manifests. But our default values are still far from real needs. Also, they are not configurable via UI, but it's easy to change them after deployment manually.
I propose:
1) allow a Fuel user to set the ratios on the Settings tab,
or
2) just document how to do it after the installation.

I prefer #2. It should be something like:
*) Read about overcommitment support [0],
*) Fuel uses ratios 8/1/1 for CPU/RAM/HDD
*) If you don't like that, go to /etc/nova/nova.conf at the Controller nodes , change the values and restart nova-scheduler service.

Links:
[0] http://docs.openstack.org/trunk/openstack-ops/content/compute_nodes.html#overcommit
Conversation in Fuel-dev ML about the problem https://www.mail-archive.com/fuel-dev%40lists.launchpad.net/msg00642.html
Initial blueprint of scheduler improvements for 5.0 https://blueprints.launchpad.net/fuel/+spec/scheduler-config-improvements
Thread in Openstack-dev ML about moving overcommit calculations out of scheduler into the resource tracker http://osdir.com/ml/openstack-dev/2014-06/msg00138.html

[Meg McRoberts (dreidellhasa)]

Neither the filter scheduler nor the overcommit ratio made it into the 5.0 or 4.1.1 Release Notes -- this seems like something we should fix while we're documenting this.

[Bogdan Dobrelya (bogdando)]

Note that after the next patching OSt with puppet (in 5.1 release) all manually made configuration changes will be ensured back to ones provided with manifests

[Meg McRoberts (dreidellhasa)]

Thanks for pointing this out, Bogdan. I'm going to do the first write-up
without this information,
in case we want to apply it to the stable/4.1 and stable/5.0 trees. As
soon as either that is done
or we decide not to do it, I'll omit this.

Meanwhile, can you clarify what the ramifications are. For the 5.0/4.1.1
implementation, to adjust
the overcommit ratio, I need to manually modify the /etc/nova/nova.conf
file on each commute node,
correct? If I redeploy my environment, I will certainly lose this, but it
will persist across reboots of the
node, correct?

So what is the advantage of having the changes ensured back to ones
provided with manifests?
Will it mean I can make the modification on one Compute node and have it
replicated to all other
Compute nodes?

On Tue, Jun 24, 2014 at 12:59 AM, Bogdan Dobrelya <email address hidden>
wrote:

> Note that after the next patching OSt with puppet (in 5.1 release) all
> manually made configuration changes will be ensured back to ones
> provided with manifests
>
> ** Changed in: fuel
> Status: Confirmed => Triaged
>
> --
> You received this bug notification because you are a bug assignee.
> https://bugs.launchpad.net/bugs/1333436
>
> Title:
> Unable to set custom overcommit ratio
>
> Status in Fuel: OpenStack installer that works:
> Triaged
>
> Bug description:
> In 5.0 (and 4.1.1 afterward) we implemented custom overcommit ratios for
> Nova Scheduler in Puppet manifests. But our default values are still far
> from real needs. Also, they are not configurable via UI, but it's easy to
> change them after deployment manually.
> I propose:
> 1) allow a Fuel user to set the ratios on the Settings tab,
> or
> 2) just document how to do it after the installation.
>
> I prefer #2. It should be something like:
> *) Read about overcommitment support [0],
> *) Fuel uses ratios 8/1/1 for CPU/RAM/HDD
> *) If you don't like that, go to /etc/nova/nova.conf at the Controller
> nodes , change the values and restart nova-scheduler service.
>
> Links:
> [0]
> http://docs.openstack.org/trunk/openstack-ops/content/compute_nodes.html#overcommit
> Conversation in Fuel-dev ML about the problem
> https://www.mail-archive.com/fuel-dev%40lists.launchpad.net/msg00642.html
> Initial blueprint of scheduler improvements for 5.0
> https://blueprints.launchpad.net/fuel/+spec/scheduler-config-improvements
> Thread in Openstack-dev ML about moving overcommit calculations out of
> scheduler into the resource tracker
> http://osdir.com/ml/openstack-dev/2014-06/msg00138.html
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/fuel/+bug/1333436/+subscriptions
>

[Dmitriy Novakovskiy (dnovakovskiy)]

Related to BP: https://blueprints.launchpad.net/fuel/+spec/cpu-overcommit-setting

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/102380

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/102380
Committed: https://git.openstack.org/cgit/stackforge/fuel-docs/commit/?id=612875721c0b2b8d5a708cbb0d7454aa3ff5c50b
Submitter: Jenkins
Branch: master

commit 612875721c0b2b8d5a708cbb0d7454aa3ff5c50b
Author: Meg McRoberts <email address hidden>
Date: Tue Jun 24 15:58:24 2014 -0700

    Document Filter Scheduler and overcommit ratio

    Terminology: add "Scheduler" and "Overcommit ratio" articles.

    User guide: add section with graphic for Settings page where one
    can select the older scheduler

    Release Notes: add sections for "Filter Scheduler" and "Overcommit ratio"
    to 030-other-enhancements

    Change-Id: Ie48d69461da1427d31b67f916d5e1a2abed95e91
    Closes-Bug: 1333436

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/5.0
Review: https://review.openstack.org/110840

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/110840
Committed: https://git.openstack.org/cgit/stackforge/fuel-docs/commit/?id=ed485904073b8baf1679c726bab266dc9f78d172
Submitter: Jenkins
Branch: stable/5.0

commit ed485904073b8baf1679c726bab266dc9f78d172
Author: Meg McRoberts <email address hidden>
Date: Tue Jun 24 15:58:24 2014 -0700

    Document Filter Scheduler and overcommit ratio

    Terminology: add "Scheduler" and "Overcommit ratio" articles.

    User guide: add section with graphic for Settings page where one
    can select the older scheduler

    Release Notes: add sections for "Filter Scheduler" and "Overcommit ratio"
    to 030-other-enhancements

    Change-Id: Ie48d69461da1427d31b67f916d5e1a2abed95e91
    Closes-Bug: 1333436

[Fabrizio Soppelsa (fsoppelsa)]

I find it unclear: pages/terminology/o/overcommit.rst

Shouldn't the overcommit ratio set by Fuel be 8:1 for CPUs? https://review.openstack.org/#/c/90426/1

- Edit the */etc/nova/nova.conf* file to change the values.

Which ones? I guess

# cat /etc/nova/nova.conf | grep ratio
ram_allocation_ratio=1.0
disk_allocation_ratio=1.0
cpu_allocation_ratio=8.0

- Log into each controller node and restart the nova-scheduler service.

Isn't required to restart any service on the compute nodes?