Chapter 3. Planning your Overcloud

The following section provides some guidelines on planning various aspects of your Red Hat OpenStack Platform environment. This includes defining node roles, planning your network topology, and storage.

3.1. Planning Node Deployment Roles

The director provides multiple default node types for building your Overcloud. These node types are:
Controller
Provides key services for controlling your environment. This includes the dashboard (horizon), authentication (keystone), image storage (glance), networking (neutron), orchestration (heat), and high availability services.

Note

Environments with one node can be used for testing purposes. Environments with two nodes or more than three nodes are not supported.
Compute
A physical server that acts as a hypervisor, and provides the processing capabilities required for running virtual machines in the environment. A basic Red Hat OpenStack Platform environment requires at least one Compute node.
Ceph-Storage
A host that provides Red Hat Ceph Storage. Additional Ceph Storage hosts scale into a cluster. This deployment role is optional.
Cinder-Storage
A host that provides external block storage for OpenStack's cinder service. This deployment role is optional.
Swift-Storage
A host that provides external object storage for OpenStack's Swift service. This deployment role is optional.
The following table provides some example of different Overclouds and defines the node types for each scenario.

Table 3.1. Node Deployment Roles for Scenarios

Controller
Compute
Ceph-Storage
Swift-Storage
Cinder-Storage
Total
Small Overcloud
1
1
-
-
-
2
Medium Overcloud
1
3
-
-
-
4
Medium Overcloud with additional Object and Block storage
1
3
-
1
1
6
Medium Overcloud with High Availability
3
3
-
-
-
6
Medium Overcloud with High Availability and Ceph Storage
3
3
3
-
-
9