Host Aggregates
In OpenStack host aggregates is a way to partition the cloud, or a region of OpenStack cloud into groups based on some characteristics. For example, we want a group of high performing SSD storage nodes into a group such that a specific ssd flavor can only be build into these hosts. Host aggregates are not exposed to the end user, instead, cloud admins map different scheduling or flavor or image to a host aggregate. Host aggregates can also be tied to an avalibility zone (AZ) in OpenStack.
To create a host aggregate called P40 :
Once the aggregate is created, add the host(s) we want in that aggregate:
PCI Device Example
Lets take and example where we want a group of GPU hosts to be formed into an aggregate, and use traits and scheudling to ensure that only GPU specific flavors. In this example, we create a custom trait, then associate hosts to the aggregate and finally use the trait to restrict flavors with the trait to build on the aggregate.
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First lets create a host aggrgate called GPU.
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Add hosts to the aggregate
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Create a custom trait called HW_GPU
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For each hypervisor in the aggregate add the trait
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Set the trait on the aggregate
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Assuming you have a flavor called gpu-flavor1
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Set Isolating Aggregate Filtering to enabled in nova.conf