Scaling control and network services
When more compute services are added to the cluster, OpenStack's scheduler distributes the new instances appropriately. When new control or network services are added, traffic has to be deliberately sent to them. There isn't anything in OpenStack that handles traffic being distributed across the API services. There is a load-balancing service called HAProxy that can do this for us. HAProxy can be run anywhere it can access the endpoints that you will be balancing. It could go on its own node or it could be put on a node that already has a bit of OpenStack installed on it. Let's put it on the first control node in our example. Start by installing it:
control# yum install -y haproxy
HAProxy has a concept of frontends and backends. The frontends are where HAProxy listens for incoming traffic, and the backends define where the incoming traffic will be sent to and balanced across. Some of the services will need additional configuration beyond HAProxy to be...
