API: Add soft-affinity policy for server-group
As a tenant I would like to schedule instances on the same host if possible,
so that I can achieve colocation. However if it is not possible to schedule
some instance to the same host then I still want that the subsequent
instances are scheduled together on another host. In this way I can express
a good-to-have relationship between a group of instances.
As a tenant I would like to schedule instances on different hosts if possible.
However if it is not possible I still want my instances to be scheduled even
if it means that some of them are placed on a host where another instances
are runnig from the same group.
End User might want to have a less strict affinity and anti-affinity
rule than what is today available in server-group API extension.
With the proposed good-to-have affinity rule the End User can request nova
to schedule the instance to the same host if possible. However if it is not
possible (e.g. due to resource limitations) then End User still wants to keep
the instances on a small amount of different host.
With the proposed good-to-have anti-affinity rule the End User can request
nova to spread the instances in the same group as much as possible.
This change would extend the existing server-group API extension with two new
policies soft-affinity and soft-anti-affinity.
When a instance is booted into a group with soft-affinity policy the scheduler
will use a new weight AffinityWeight to sort the available hosts according to
the number of instances running on them from the same server-group in a
descending order.
When an instance is booted into a group with soft-anti-affinity policy the
scheduler will use a new weight AntiAffinityWeight to sort the available hosts
according to the number of instances running on them from the same
server-group in a ascending order.
The two new weigh will get the necessary information about the number of
instances per host through the weight_properties (filter_properties) in
a similar way as the GroupAntiAffini
a group via the filter_properties.
These new soft-affinity and soft-anti-affinity policies are mutually exclusive
with each other and with the other existing server-group policies.
Blueprint information
- Status:
- Complete
- Approver:
- John Garbutt
- Priority:
- Low
- Drafter:
- Balazs Gibizer
- Direction:
- Approved
- Assignee:
- Balazs Gibizer
- Definition:
- Approved
- Series goal:
- Accepted for mitaka
- Implementation:
-
Implemented
- Milestone target:
-
mitaka-2
- Started by
- Balazs Gibizer
- Completed by
- John Garbutt
Related branches
Sprints
Whiteboard
Gerrit topic: https:/
Addressed by: https:/
Add soft policies for server-group feature
Addressed by: https:/
Add functional test for server group
Addressed by: https:/
scheduler: add soft-(anti-
Addressed by: https:/
scheduler: add instance count to filter_properties
Addressed by: https:/
api: add soft-affinity policies for server groups
Addressed by: https:/
Add functional tests to soft affinity capabilities
Addressed by: https:/
scheduler:
Addressed by: https:/
scheduler: add num of instance per host in a group
Addressed by: https:/
Fix leaking exceptions from scheduler utils
Addressed by: https:/
object: serialize set to list
This isn't going to make it for kilo, lets delay this to L --johnthetubaguy 4th Feb 2015
Addressed by: https:/
Add soft policies for server-group feature
Sorry, we have now hit the non-priority feature freeze for Liberty. You will need to resubmit this blueprint for Mitaka or apply for an exception. For more details on why this is happening, and the rest of the process details, please see: https:/
--johnthetubaugy 3rd July 2015
Addressed by: https:/
api: add soft-affinity policies for server groups
Gerrit topic: https:/
Addressed by: https:/
Add soft policies for server-group feature
Addressed by: https:/
Modify Scheduler RPC API to use RequestSpec obj
Addressed by: https:/
Modify conductor to use RequestSpec object
While there is python-novaclient work, technically the nova part of this is now complete, so marking this as complete. --johnthetubaguy 2015.01.15
Addressed by: https:/
Adds relase notes for soft affinity feature
Work Items
Dependency tree
* Blueprints in grey have been implemented.
