Containers based Overcloud Deployment

This documentation explains how to deploy a fully containerized overcloud utilizing Podman which is the default since the Stein release.

The requirements for a containerized overcloud are the same as for any other overcloud deployment. The real difference is in where the overcloud services will be deployed (containers vs base OS).


The container-based overcloud architecture is not very different from the baremetal/VM based one. The services deployed in the traditional baremetal overcloud are also deployed in the docker-based one.

One obvious difference between these two types of deployments is that the Openstack services are deployed as containers in a container runtime rather than directly on the host operating system. This reduces the required packages in the host to the bare minimum for running the container runtime and managing the base network layer.

Manual overcloud deployment

This section explains how to deploy a containerized overcloud manually. For an automated overcloud deployment, please follow the steps in the Using TripleO Quickstart section below.

Preparing overcloud images

As part of the undercloud install, an image registry is configured on port 8787. This is used to increase reliability of overcloud image pulls, and minimise overall network transfers. The undercloud registry will be populated with images required by the overcloud deploy by generating the following containers-prepare-parameter.yaml file and using that for the prepare call:

openstack tripleo container image prepare default \
  --local-push-destination \
  --output-env-file containers-prepare-parameter.yaml


The file containers-prepare-parameter.yaml may have already been created during Installing the Undercloud. It is encouraged to share the same containers-prepare-parameter.yaml file for undercloud install and overcloud deploy.

See Container Image Preparation for details on using containers-prepare-parameter.yaml to control what can be done with image preparation during overcloud deployment.

Deploying the containerized Overcloud

A containerized overcloud deployment follows all the steps described in the baremetal Deploy the Overcloud documentation with the exception that it requires an extra environment file to be added to the openstack overcloud deploy command:

-e ~/containers-prepare-parameter.yaml

If deploying with highly available controller nodes, include the following extra environment file in addition to the above and in place of the environments/puppet-pacemaker.yaml file:

-e /usr/share/openstack-tripleo-heat-templates/environments/docker-ha.yaml

Using TripleO Quickstart


Please refer to the TripleO Quickstart docs for more info about quickstart, the minimum requirements, the setup process and the available plugins.

The command below will deploy a containerized overcloud on top of a baremetal undercloud:

bash --config=~/.quickstart/config/general_config/containers_minimal.yml $VIRTHOST