Chapter 2. Process Description

Like most Red Hat OpenStack Platform features, hyper-convergence is best implemented through the director. This allows you to take advantage of existing Heat templates and environment files to orchestrate your deployment.

On the other hand, the director’s infrastructure also provides a framework you can use to define your own Heat templates and environment files. This is useful when the existing ones do not cover your specific use case.

The following subsections briefly describe each step of the deployment process.

Prepare Overcloud Role for Hyper-Converged Nodes
To use hyper-converged nodes, you need to define a role for it. Red Hat OpenStack Platform provides default roles for normal overcloud nodes (for example, Controller, Compute, and Ceph Storage), as well as a predefined role for hyper-converged nodes, ComputeHCI. To use the ComputeHCI role, you need to generate a custom roles_data.yaml file that includes it, along with all the other roles you are using in your deployment.
Configuring Resource Isolation
When you deploy HCI, Compute and Ceph Storage services need to be aware of each other as hyper-converged nodes. Otherwise, both services will consume resources as if they were on dedicated nodes. This can lead to resource contention, which can lead to performance degradation.
Configure Networking
When using hyper-converged nodes, you need to map the StorageMgmtNetwork ports to the right NICs. During this step, you can implement any other networking settings required in your environment.
The deployment process for HCI involves specifying which environment files to include in the deployment. This involves defining a new flavor for the ComputeHCI role, tagging it to hyper-converged nodes, and invoking the custom roles_data.yaml file (from Chapter 3, Prepare Overcloud Role for Hyper-Converged Nodes) during deployment.