.. This work is licensed under a Creative Commons Attribution 4.0 International License.
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Service Discovery
=================

Service discovery is an architecture pattern used for components
(micro-services) to locate each other. The DCAE platform uses
`server-side
discovery <http://microservices.io/patterns/server-side-discovery.html>`__
and is using `Consul <https://www.consul.io/>`__ as the service registry
solution.

Service Registration
--------------------

All components are required to register with Consul in order to be
discovered. There are two methods of registration: self and 3rd party.
The DCAE platform uses 3rd party registration which means components
don’t actually make the registration calls but defers that
responsibility to a platform service.

Implementation for Docker
~~~~~~~~~~~~~~~~~~~~~~~~~

`Registrator <http://gliderlabs.com/registrator/latest/>`__ is an open
source application that is responsible for registering all components
that run as Docker containers. Registrator watches the local Docker
engine’s activity log and will register and unregister a Docker
container when the container is started and stopped.

Implementation for CDAP
~~~~~~~~~~~~~~~~~~~~~~~

The CDAP broker is a REST web service that is responsible for
registering all components that run as CDAP applications.