How to Setup resource allocation ratios in PCD for the hosts in cluster?

Problem

How to setup and configure host resource like cpu, memory and disk allocation ratio in PCD?

How to ensure the instances are spawned on hosts with specific resource allocation ratio mapped?

Environment

Private Cloud Director Virtualization - v2025.6 and Higher
Self-Hosted Private Cloud Director Virtualization - v2025.6 and Higher

Procedure

Info

It is necessary to ensure that the target set of hosts to be used for the isolation should belong to a PCD host cluster and should be added to the newly created aggregate from the UI

From the PCD UI create a host cluster and add the required hosts
From the PCD UI create an aggregate with required hosts mapped into it.
Set the required metadata tag to the aggregate:

Create a flavor with matching metadata to the aggregate thus created:

From the clusters host page, select the specific host that is part of the host aggregate as well the host cluster and set the allocation ratio values:

Validation

Deploy an instance by selecting the cluster to which the specific host belongs:

In the next section select the flavor that has the specific tag matching and applied:

Complete the subsequent instance creation form and continue to deploy the VM.

Additional Information

The actual allocation ratios will be placed within the placement API DB instead of host-level changes.
When successfully applied, the values can be reviewed by looking at the resource provider inventory list for the specific hosts:

$ openstack resource provider list +-------------------+---------------------+------------+--------------------+----------------------+ | uuid | name | generation | root_provider_uuid | parent_provider_uuid | +-------------------+---------------------+------------+--------------------+----------------------+ | [RESOURCE1_UUID] | [HOST1.EXAMPLE.COM] | 4 | [PROVIDER1_UUID] | None | | [RESOURCE2_UUID] | [HOST2.EXAMPLE.COM] | 8 | [PROVIDER2_UUID] | None | | [RESOURCE3_UUID] | [HOST3.EXAMPLE.COM] | 4 | [PROVIDER3_UUID] | None | | [RESOURCE4_UUID] | [HOST4.EXAMPLE.COM] | 3 | [PROVIDER4_UUID] | None | +-------------------+---------------------+------------+--------------------+----------------------+ $ openstack resource provider inventory list <RESOURCE1_UUID> +----------------+------------------+----------+----------+----------+-----------+-------+------+ | resource_class | allocation_ratio | min_unit | max_unit | reserved | step_size | total | used | +----------------+------------------+----------+----------+----------+-----------+-------+------+ | VCPU | 1.0 | 1 | 8 | 0 | 1 | 8 | 0 | | MEMORY_MB | 1.0 | 1 | 15988 | 512 | 1 | 15988 | 0 | | DISK_GB | 9999.0 | 1 | 125 | 0 | 1 | 125 | 0 | +----------------+------------------+----------+----------+----------+-----------+-------+------+

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