How to make a client for multiple hosts

Consul
1

first, i build the consul cluster on my three server machine, which have three consul server and three consul client.

And i try to use https://github.com/hashicorp/consul/api for my golang code to connect consul cluster.

but it seems that the config param of <api.NewClient> function can only fill the string type Address, so that i can’t fill my three hosts

how should i config correctly ?
thanks !

2

Hi @linsijia1002,

Normally API clients just make a connection to a single Consul agent for all operations.

Is there a particular reason your application needs to communicate with multiple Consul agents?

3

hi @blake ,
yes , because the high available.
When the machine which is connected is down, it means the application is lose connection with the consul cluster.
Normally like redis cluster, or kafka cluster , client application fill multiple hosts to insure the high available.
So i want to know what should i do in consul cluster

4

In this case, you should run multiple instances of your application on each server that is running a Consul agent. The application should register itself into the Consul catalog by communicating with the Consul agent running on the same machine.

When other services query the catalog (https://learn.hashicorp.com/tutorials/consul/get-started-service-discovery#query-services) for the service name, Consul will respond with the IP addresses of each registered, healthy service instance.

5

Ok，i get you mean，i will try. thank you.
By the way, in your plan, is HTTP API better or DNS more recommended ?
I usually use the HTTP API.
Thank you.

6

Its really a matter of preference, and what your requirements are. The HTTP interface offers a bit more flexibility in terms of filtering and provides more information in its responses compared to what is in a DNS response.

If the HTTP API works well for your needs then you should continue to use it. :slight_smile:

7

Hi @blake ,
I have a question to ask. Let’s say we have Consul running in ensemble mode with 3 servers. Now, if Consul Server 1 goes down and we need to register a new service from that instance, what is the appropriate way to achieve this?

8

Hi @akashdeepb7,

I recently answered a similar question in another thread. Take a look at my replies there. I believe they will answer your question.