Execute the following command on the controller node to install the various Compute services used by the controller:

    # apt install nova-api nova-conductor nova-consoleauth
      nova-novncproxy nova-scheduler nova-placement-api

Update the [database] and [api_database] sections of the Nova configuration file found at /etc/nova/nova.conf with the following database connection strings:

[database]
...
connection = mysql+pymysql://nova:nova@controller01/nova 

[api_database]
...
connection = mysql+pymysql://nova:nova@controller01/nova_api 

Update the [DEFAULT] section of the Nova configuration file to configure Nova to use the RabbitMQ message broker:

[DEFAULT]
...
transport_url = rabbit://openstack:rabbit@controller01 

The VNC Proxy is an OpenStack component that allows users to access their instances through VNC clients. VNC stands for Virtual Network Computing, and is a graphical desktop sharing system that uses the Remote Frame Buffer protocol to control another computer over a network. The controller must be able to communicate with compute nodes for VNC services to work properly through the Horizon dashboard or other VNC clients.

Update the [vnc] section of the Nova configuration file to configure the appropriate VNC settings for the controller node:

[vnc]
...
enabled = true
vncserver_listen = 10.10.0.100
vncserver_proxyclient_address = 10.10.0.100