yahoo-eng-team team mailing list archive

[Matthew Booth <mbooth@xxxxxxxxxx>]

Public bug reported:

A VMware hypervisor can have various types of non-contiguous resource.
This includes:

* CPUs and memory, assuming a cluster has more than 1 member.
* Storage space, if a (VMware) host has more than 1 datastore.

Focussing on the latter, if a host has 5 datastores, each with 50GB of
free space, we currently report the largest contiguous free space to the
hypervisor: 50GB. This means that the scheduler knows it can allocate an
instance with a 50GB block device, but until the host stats are updated
it will not allow subsequent instances to be scheduled there. We could
alternatively report 250GB of free space, but would risk the scheduler
repeatedly sending us a request for an instance with a 100GB block
device, which we cannot fulfil. Without the ability to represent non-
contiguous resources we are left choosing between 2 suboptimal choices.

** Affects: nova
     Importance: Undecided
         Status: New

-- 
You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to OpenStack Compute (nova).
https://bugs.launchpad.net/bugs/1462957

Title:
  VMware driver cannot report non-contiguous resources to the scheduler

Status in OpenStack Compute (Nova):
  New

Bug description:
  A VMware hypervisor can have various types of non-contiguous resource.
  This includes:

  * CPUs and memory, assuming a cluster has more than 1 member.
  * Storage space, if a (VMware) host has more than 1 datastore.

  Focussing on the latter, if a host has 5 datastores, each with 50GB of
  free space, we currently report the largest contiguous free space to
  the hypervisor: 50GB. This means that the scheduler knows it can
  allocate an instance with a 50GB block device, but until the host
  stats are updated it will not allow subsequent instances to be
  scheduled there. We could alternatively report 250GB of free space,
  but would risk the scheduler repeatedly sending us a request for an
  instance with a 100GB block device, which we cannot fulfil. Without
  the ability to represent non-contiguous resources we are left choosing
  between 2 suboptimal choices.

To manage notifications about this bug go to:
https://bugs.launchpad.net/nova/+bug/1462957/+subscriptions