Forwarding Traffic to and Load Balancing Internal Endpoints with Cloud Endpoints

This guide provides an example of using an ngrok Cloud Endpoint to route traffic to an internal endpoint.

Core Concepts

• Cloud endpoints are centrally managed endpoints in the cloud that can be used to route traffic to agent endpoints.
• Internal endpoints are endpoints that are not publicly accessible and are only reachable from within your network by cloud endpoints via the forward action.
• Load balancing improves application performance and reduces load by distributing incoming traffic across servers. This leads to faster response times for user-facing applications.

Prerequisites

To follow this guide, you will need a computer with ngrok installed. You can download ngrok here..

Step 1 — Reserve a domain

Visit https://dashboard.ngrok.com/domains and reserve a domain. This will be how your end users access your endpoint in the browser.

Step 2 — Create a public cloud endpoint

Once you've reserved a domain, visit https://dashboard.ngrok.com/endpoints to create a public endpoint linked to that domain

Step 3 — Create a Traffic Policy for your cloud endpoint

Cloud endpoints require a traffic policy so they know how to handle incoming traffic. This guide will showcase one of the simplest and most common use cases: forwarding traffic to a private endpoint via the forward-internal action.

YAML

---
on_http_request:
  - actions:
      - type: forward-internal
        config:
          url: https://the-internal-endpoint.internal

JSON

{
  "on_http_request": [
    {
      "actions": [
        {
          "type": "forward-internal",
          "config": {
            "url": "https://the-internal-endpoint.internal"
          }
        }
      ]
    }
  ]
}

Step 4 — Start an agent session

At this point, you have a public endpoint with a domain and a traffic policy routing to the URL we defined in our traffic policy above, https://the-internal-endpoint.internal. But that URL doesn't exist on the public internet; we need to start an agent session so that requests to our public endpoint will be routed to our internal endpoint, served by the ngrok agent. So, locally, start an agent session with:

ngrok http 80 --url=https://the-internal-endpoint.internal

Make sure you have some sample application running on port 80.

Step 5 — See your endpoint in action

Visit the public endpoint you created in Step 1 and see that you're routed to whatever application your ngrok agent is serving.

Step 5 — Load Balancing with Endpoint Pools

warning

Endpoint pools are currently in private beta. The functionality described below is not yet publicly available.

Load balancing is simple with ngrok Endpoint Pools. Simply start another agent with the same internal endpoint URL, and the traffic will be automatically load balanced between the two agents in the pool!

ngrok http 80 --url=https://the-internal-endpoint.internal

Conclusion

And you're done! You've successfully created a cloud endpoint that can be accessed from the URL you reserved. The cloud endpoint will refer to its traffic policy and forward traffic to our internal endpoint. The internal endpoint finally exposes the local port on which it was created on in Step 1.