Appendix F. Changing Nova reserved memory and CPU allocation manually

Creating a custom template to overwrite the reserved_host_memory_mb and cpu_allocation_ratio default values.

Prerequisites

  • Deploy the Red Hat OpenStack Platform director (RHOSP-d), also known as the undercloud.
  • Create a Directory for Custom Templates.

Procedure

Do the following steps on the RHOSP-d node, as the stack user.

  1. Create the compute.yaml file in the custom templates directory: 

    [stack@director ~]$ touch ~/templates/compute.yaml

  2. Open the compute.yaml file for editing.

    1. Add the reserved_host_memory and cpu_allocation_ratio configuration parameters to the ExtraConfig section, under the parameter defaults section: 

      parameter_defaults:
  ExtraConfig:
    nova::compute::reserved_host_memory: MEMORY_SIZE_IN_MB
    nova::cpu_allocation_ratio: CPU_RATIO
      Replace…​
      • MEMORY_SIZE_IN_MB with the memory size in megabytes (MB).

      • CPU_RATIO with the ratio decimal value.

        Example

            nova::compute::reserved_host_memory: 75000
    nova::cpu_allocation_ratio: 8.2

        Note

        Red Hat OpenStack Platform director refers to the reserved_host_memory_mb parameter used by Nova as the reserved_host_memory parameter.