The use of 'include_tasks' and a loop of variables creates
a situation where a user is unable to use tags to scope the
inclusion of only the MQ tasks when running the playbooks.
The use-case this is important for is when the rabbitmq
containers are destroyed and rebuilt in order to resolve
an issue with them, and the user wishes to quickly recreate
all the vhosts/users.
Ansible's 'include_tasks' is a dynamic inclusion, and dynamic
inclusions are not included when using tags. The nice thing
about dynamic inclusions is that they completely skip all
tasks when the condition does not apply, cutting down deploy
time. However, given the use-case, we should rather take on
the extra deployment time.
This patch changes the dynamic inclusion to a static one,
adds a 'common-mq' tag to cover all MQ implementations,
and re-implements the 'common-rabbitmq' tag for the tasks
that relate to RabbitMQ specifically.
It also implements conditionals for each task set so that
the rpc/notify tasks can be skipped if a vhost/user is not
required for that purpose (eg: swift does not use RPC, and
most roles will not use notifications by default).
Depends-On: https://review.openstack.org/588191
Change-Id: Ied4df931d0464173649c39ac82253c541b195cb1