Compact deployment mode requires fewer hardware resources and less memory than HA mode.

A compact deployment runs on one ESXi host with two virtual machines. All control plane instances are deployed on a single virtual machine, and the compute node is deployed on the second virtual machine. The deployment includes only one controller, message queue, and database instance.

Figure 1. Management Cluster in Compact Mode
Management cluster in compact mode

Compact deployment mode is suitable for evaluation and proof of concept testing. If you enable HA or make regular backups of your virtual machines, it can also be used in production environments.

HA in Compact Mode

You can enable HA on a compact deployment to provide automatic failover of the control plane virtual machines and OpenStack services. HA in compact mode can protect against the following errors:

  • An ESXi host stops functioning, loses network connectivity with the master host, or enters the Network Isolated state.

  • A control plane or compute virtual machine stops functioning.

  • OpenStack services stop functioning

In addition, vSAN provides fault tolerance for storage components.

If you want to enable HA mode on a compact deployment, you must have a vSphere cluster including three ESXi hosts and using vSAN as the management cluster. You then enable vSphere HA and VM monitoring on the management cluster. If you are deploying OpenStack using the public API, you can enable HA by setting the attribute "control_plane_ha_enabled": "true".