kolla-ansible/doc/source/reference/resource-constraints.rst

Resource Constraints in Kolla Ansible

Overview

Since the Rocky release it is possible to restrict the resource usage of deployed containers. The following components support this feature:

• Nova

In Kolla Ansible, container resources to be constrained are referred to as dimensions.

The Docker documentation provides information on container resource constraints. The resources currently supported by Kolla Ansible are:

cpu_period
cpu_quota
cpu_shares
cpuset_cpus
cpuset_mems
mem_limit
mem_reservation
memswap_limit
kernel_memory
blkio_weight

Pre-deployment Configuration

Dimensions are defined as a mapping from a Docker resource name (e.g. cpu_period) to a string constraint value.

The variable default_container_dimensions sets the default dimensions for all supported containers, and by default these are unconstrained.

Each supported container has an associated variable, <container name>_dimensions, that can be used to set the resources for the container. For example, dimensions for the nova_libvirt container are set via the variable nova_libvirt_dimensions.

For example, to constrain the number of CPUs that may be used by all supported containers, add the following to the dimensions options section in /etc/kolla/globals.yml:

default_container_dimensions:
  cpuset_cpus: "1"

For example, to constrain the number of CPUs that may be used by the nova_libvirt container, add the following to the dimensions options section in /etc/kolla/globals.yml:

nova_libvirt_dimensions:
  cpuset_cpus: "2"

Deployment

To deploy resource constrained containers, run the deployment as usual:

$ kolla-ansible deploy -i /path/to/inventory