Chapter 4. Deploying the central controllers

Deploy the central controller cluster in a similar way to a typical overcloud deployment. This cluster does not require any Compute nodes, so you can set the Compute count to 0 to override the default of 1. The central controller has particular storage and Oslo configuration requirements. Use the following procedure to address these requirements.

Procedure

  1. Create a file called central/overrides.yaml with settings similar to the following: 

    parameter_defaults:
  NtpServer:
    - 0.pool.ntp.org
    - 1.pool.ntp.org
  ControllerCount: 3
  ComputeCount: 0
  OvercloudControlFlavor: baremetal
  OvercloudComputeFlavor: baremetal
  ControllerSchedulerHints:
    'capabilities:node': '0-controller-%index%'
  GlanceBackend: swift
    • ComputeCount: 0 is an optional parameter to prevent Compute nodes from being deployed with the central Controller nodes.

    • GlanceBackend: swift uses Object Storage (swift) as the Image Service (glance) back end. Red Hat recommends that the Image service does not use Ceph in this configuration until multi-backend glance support is available.

      The resulting configuration interacts with the distributed compute nodes (DCNs) in the following ways:

    • The Image service on the DCN creates a cached copy of the image it receives from the central Object Storage back end. The Image service uses HTTP to copy the image from Object Storage to the local disk cache.

    • Each DCN has its own Object Storage volume service. This means that users can schedule Object Storage volumes from the central node into different availability zones, because the Ceph volume service on the DCN uses the local Ceph cluster.

      Note

      The central Controller node must be able to connect to the distributed compute node (DCN) site. The central Controller node can use a routed layer 3 connection.

  2. Deploy the central Controller node. For example, you can use a deploy.sh file with the following contents: 

    #!/bin/bash

STACK=central
source ~/stackrc
time openstack overcloud deploy \
     --stack $STACK \
     --templates /usr/share/openstack-tripleo-heat-templates/ \
     -e /usr/share/openstack-tripleo-heat-templates/environments/podman.yaml \
     -e ~/containers-env-file.yaml \
     -e ~/central/overrides.yaml