Why do I need service discovery?
Server-side service discovery allows clients applications to find services through a router or a load balancer. Client-side service discovery allows clients applications to find services by looking through or querying a service registry, in which service instances and endpoints are all within the service registry.
What is the use of Eureka service Registry?
You will set up a Netflix Eureka service registry and then build a client that both registers itself with the registry and uses it to resolve its own host. A service registry is useful because it enables client-side load-balancing and decouples service providers from consumers without the need for DNS.
When do microservices need to interact with the registry?
Whenever a service endpoint changes, the registry needs to know about the change. This is what registration is all about: who publishes or updates the information on how to reach each service. Self-registration forces microservices to interact with the registry by themselves. When a service goes up, it notifies the registry.
How are services registered in a service registry?
Implement a service registry, which is a database of services, their instances and their locations. Service instances are registered with the service registry on startup and deregistered on shutdown.
Is the service registry a critical system component?
Moreover, the service registry is a critical system component. Although clients should cache data provided by the service registry, if the service registry fails that data will eventually become out of date. Consequently, the service registry must be highly available.
When does the registry need to know about a change?
Services go up and down as development teams split, improve, deprecate and do their work. Whenever a service endpoint changes, the registry needs to know about the change. This is what registration is all about: who publishes or updates the information on how to reach each service.