Registration patterns – self-registration

While using this pattern, any microservice instance is responsible for registering and deregistering itself from the maintained service registry. To maintain health checks, a service instance sends heartbeat requests to prevent its registry from expiring. Netflix uses a similar approach and has outsourced their Eureka library, which handles all aspects of service registration and deregistration. It has its client in Java as well as Node.js. The Node.js client (eureka-js-client) has more than 12,000 downloads a month. The self-registration pattern has major benefits, such as any microservice instance would know its own state, hence it can implement or shift to other modes easily such as Starting, Available, and others.

However, it also has the following drawbacks:

• It couples the service tightly to the self-service registry, which forces us to enable the service registration code in each language we are using in the framework
• Any microservice that is in running mode, but is not able to handle requests, will often be unaware of which state to pursue, and will often end up forgetting to unregister from the registry