What are quotas? Within OpenStack, you can set quotas on a tenant/project or user level in order to restrict the resource consumption that is allowed. The compute service (Nova) manages the quota values and also enforces them. As a cloud operator, this is another important feature OpenStack offers, as quotas allow you to control the cloud's overall system capacity. You may ask, why not just set up one default quota and let every tenant use it? We will cover why this approach may or may not work, based on a particular use case. It is also worth mentioning that the Block Storage service (Cinder) can also set quotas.
Since we now know that you can set quotas, let's review the resources that can be restricted and what the default values are. The following is a table describing the type of quotas that can be set:
Quota name |
Defines the number of... |
---|---|
Instances |
Instances allowed for each project |
Cores |
Instance cores allowed for each project |
RAM (MB) |
RAM megabytes... |