Consul Port Redirector

A basic HTTP server written in Go, which when a request is received with a HTTP Host header ending in .service.consul, queries Consul for the service port(s) which are matched by that Consul DNS query, and either redirects to or displays a list of those service ports.

This is intended to run as a Nomad system job, running on every Nomad Client on port 80. When deployed as such, then Nomad services can be accessed in a web browser via their Consul Service names, without remembering their port numbers and while also allowing easy access to individual instances of a service.

Setup

First, ensure that Nomad is properly configured to utilize Consul, and that every Nomad client has a running Consul agent.

Apply port-redirector.nomad.hcl to an existing Nomad cluster:

$ nomad job run port-redirector.nomad.hcl

Note that because the job binds on port 80, Nomad must be running as root on all clients. You can adjust which nodes the job is deployed on using a constraint.

Usage

To see all ports registered in Consul for the nomad service:

• http://nomad.service.consul
• http://nomad.service.[datacenter].consul

To see all ports named http in Consul for the nomad service:

• http://_nomad._http.service.consul
• http://_nomad._http.service.[datacenter].consul

Note that Consul requires the leading underscore, and the service name comes before the port name. If only one instance matches in Consul, you will be redirected to that port. If multiple match, you will receive a basic list of linked host:ports.