consul - Consul Agent Service Registrations on other nodes are not fetchable from Rest API but is showing on UI

Question

We have a consul cluster of 3 servers and registering agent services on any of them via Rest Api.

In UI, registrations of a server are visible on other servers as well. For e.g. registration on server A is visible on server B's UI (accessible by http://serverb:8500/).

However when hitting server B via Rest Api, it only shows its own registrations and do not show server A registration.

Server are started as Server A consul -server -ui bootstrap-expect=1 -node=ServerA -data-dir=D:\data -bind=11.223.15.78 -client=0.0.0.0 -retry-join=11.223.15.79 -retry-join=11.223.15.80

Server B
consul -server -ui bootstrap-expect=1 -node=ServerB -data-dir=D:\data -bind=11.223.15.79 -client=0.0.0.0 -retry-join=11.223.15.78 -retry-join=11.223.15.80

Server C
consul -server -ui bootstrap-expect=1 -node=ServerC -data-dir=D:\data -bind=11.223.15.80 -client=0.0.0.0 -retry-join=11.223.15.78 -retry-join=11.223.15.79

Is this an issue or am I doing something wrong?

标签： consulservice-discovery

Answer 1

The visibility of services will depend on which API endpoint you're using, and where you're registering your services. Consul intends for services to be registered against a Consul client agent which is running on the same host as the deployed service. The services registered with each agent in the data center are aggregated to form the service catalog (https://www.consul.io/docs/architecture/anti-entropy#catalog).

The /catalog/services endpoint returns an aggregated list of services registered with each agent across the data center. The /agent/services endpoint will only return services registered against the specific local agent with which you are communicating.

If you want clients to be able to register services across any server, you'll want to register them using the /catalog/register endpoint. You can optionally use a tool like Consul External Services Monitor to provide health checking for services, independently from the Consul servers. See https://www.hashicorp.com/blog/consul-and-external-services for more information.