openstack-ansible/doc/source/install-guide/configure-initial.rst

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Initial environment configuration

OpenStack-Ansible depends on various files that are used to build an inventory for Ansible. Start by getting those files into the correct places:

1. Recursively copy the contents of the /opt/openstack-ansible/etc/openstack_deploy directory to the /etc/openstack_deploy directory.
2. Change to the /etc/openstack_deploy directory.
3. Copy the openstack_user_config.yml.example file to /etc/openstack_deploy/openstack_user_config.yml.

Deployers can review the openstack_user_config.yml file and make changes to how the OpenStack environment is deployed. The file is heavily commented with details about the various options.

There are various types of physical hosts that will host containers that are deployed by OpenStack-Ansible. For example, hosts listed in the shared-infra_hosts will run containers for many of the shared services required by OpenStack environments. Some of these services include databases, memcache, and RabbitMQ. There are several other host types that contain other types of containers and all of these are listed in openstack_user_config.yml.

Affinity

OpenStack-Ansible's dynamic inventory generation has a concept called affinity. This determines how many containers of a similar type are deployed onto a single physical host.

Using shared-infra_hosts as an example, let's consider a openstack_user_config.yml that looks like this:

shared-infra_hosts:
  infra1:
    ip: 172.29.236.101
  infra2:
    ip: 172.29.236.102
  infra3:
    ip: 172.29.236.103

Three hosts are assigned to the shared-infra_hosts group, so OpenStack-Ansible will ensure that each host runs a single database container, a single memcached container, and a single RabbitMQ container. Each host has an affinity of 1 by default, and that means each host will run one of each container type.

Some deployers may want to skip the deployment of RabbitMQ altogether. This is helpful when deploying a standalone swift environment. For deployers who need this configuration, their openstack_user_config.yml would look like this:

shared-infra_hosts:
  infra1:
    affinity:
      rabbit_mq_container: 0
    ip: 172.29.236.101
  infra2:
    affinity:
      rabbit_mq_container: 0
    ip: 172.29.236.102
  infra3:
    affinity:
      rabbit_mq_container: 0
    ip: 172.29.236.103

The configuration above would still deploy a memcached container and a database container on each host, but there would be no RabbitMQ containers deployed.

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