Cloned from launchpad blueprint https://blueprints.launchpad.net/nova/+spec/admin-set-resource-quota-dynamically.

Description:

This blueprint is a supplement to Instance Resource Quota (https://blueprints.launchpad.net/nova/+spec/quota-instance-resource) supported by OpenStack from Grizzly. Instance Resource Quota is a static mechanism for cloud tenants to require precisely quantitative resources, while this new blueprint helps an administrator to effectively manage and utilize the cloud hardware resouces. In detail, this blueprint enables an admin to change physical resource allocation, CPU execution time, physical memory occupation, disk I/O bandwidth and priority, after VM instances have been created and in running. The benefits could be as the following:
    - The admin can use this runtime mechanism to change physical resource allocation, if a tenant over-claims resource quota when creating instances. But the instances themselves do not need to be terminated and re-created while resources changed;
    -  The admin can also use this runtime mechanism to dynamically adjust resource quota of instances during running according to the change of instance workloads and/or priorities.

Parts of this blueprint related with VCPU performance management have been implemented in our local OpenStack Grizzly deployment and work well.

Specification URL (additional information):

https://wiki.openstack.org/wiki/Admin-set-resource-quota-dynamically