VMware content regarding scheduler granularity is confusing and incorrect

[Stephen Gordon]

The configuration reference guide [1] currently contains this statement pertaining to the VMware Nova driver:

"As the figure shows, the OpenStack Compute Scheduler sees three hypervisors that each correspond to a cluster in vCenter. nova-compute contains the VMware driver. You can run with multiple nova-compute services. While Compute schedules at the granularity of a cluster, the VMware driver inside nova-compute interacts with the vCenter APIs to select an appropriate ESX host within the cluster. Internally, vCenter uses DRS for placement."

The confusing statement is "While Compute schedules at the granularity of a cluster, the VMware driver inside nova-compute interacts with the vCenter APIs to select an appropriate ESX host within the cluster.". The Nova scheduler schedules at the granularity of the nova-compute service, in this specific example that *happens* to be the cluster as there is a 1:1 relationship between the nova-compute services and ESXi clusters in the diagram.

This is not always the case but some readers have interpreted this to mean even when there is a 1:N where N>1 relationship betweeen the nova-compute services and ESXi clusters the scheduler maintains granularity at the cluster level, which is not correct.

http://docs.openstack.org/mitaka/config-reference/compute/hypervisor-vmware.html

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/322818

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/322818
Committed: https://git.openstack.org/cgit/openstack/openstack-manuals/commit/?id=f8c0dd0fa5a33d97e759b1ce0f44846c90ac9e02
Submitter: Jenkins
Branch: master

commit f8c0dd0fa5a33d97e759b1ce0f44846c90ac9e02
Author: Stephen Gordon <email address hidden>
Date: Mon May 30 09:17:21 2016 -0400

    Clarify Nova scheduling granularity for vCenter

    Clarify Nova scheduling granularity for the vCenter driver is at the
    nova-compute service level, which in the example happens to also be the
    ESX cluster level.

    Change-Id: Id80d45142ec2f26ce4ae3a91395de432b89d1f0e
    backport: mitaka
    Closes-Bug: #1587054

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/openstack-manuals 15.0.0 release.