openstack-ansible/doc/source/admin/maintenance-tasks/containers.rst

Container management

With Ansible, the OpenStack installation process is entirely automated using playbooks written in YAML. After installation, the settings configured by the playbooks can be changed and modified. Services and containers can shift to accommodate certain environment requirements. Scaling services are achieved by adjusting services within containers, or adding new deployment groups. It is also possible to destroy containers, if needed, after changes and modifications are complete.

Scale individual services

Individual OpenStack services, and other open source project services, run within containers. It is possible to scale out these services by modifying the /etc/openstack_deploy/openstack_user_config.yml file.

1. Navigate into the /etc/openstack_deploy/openstack_user_config.yml file.

2. Access the deployment groups section of the configuration file. Underneath the deployment group name, add an affinity value line to container scales OpenStack services:

   infra_hosts:
     infra1:
       ip: 10.10.236.100
       # Rabbitmq
       affinity:
         galera_container: 1
         rabbit_mq_container: 2

   In this example, galera_container has a container value of one. In practice, any containers that do not need adjustment can remain at the default value of one, and should not be adjusted above or below the value of one.

   The affinity value for each container is set at one by default. Adjust the affinity value to zero for situations where the OpenStack services housed within a specific container will not be needed when scaling out other required services.

3. Update the container number listed under the affinity configuration to the desired number. The above example has galera_container set at one and rabbit_mq_container at two, which scales RabbitMQ services, but leaves Galera services fixed.

4. Run the appropriate playbook commands after changing the configuration to create the new containers, and install the appropriate services.

   For example, run the openstack-ansible lxc-containers-create.yml rabbitmq-install.yml commands from the openstack-ansible/playbooks repository to complete the scaling process described in the example above:

   $ cd openstack-ansible/playbooks
   $ openstack-ansible lxc-containers-create.yml rabbitmq-install.yml

Destroy and recreate containers

Resolving some issues may require destroying a container, and rebuilding that container from the beginning. It is possible to destroy and re-create a container with the lxc-containers-destroy.yml and lxc-containers-create.yml commands. These Ansible scripts reside in the openstack-ansible/playbooks repository.

1. Navigate to the openstack-ansible directory.

2. Run the openstack-ansible lxc-containers-destroy.yml commands, specifying the target containers and the container to be destroyed.

   $ openstack-ansible lxc-containers-destroy.yml --limit "CONTAINER_NAME"
   $ openstack-ansible lxc-containers-create.yml --limit "CONTAINER_NAME"

3. Replace ``CONTAINER_NAME`` with the target container.