Set Up Intelligent Load Balancing

In this topic, you’ll learn about configuring upstream services, and create multiple targets for load balancing.

If you are following the getting started workflow, make sure you have completed Secure Services Using Authentication before moving on.

What are Upstreams?

An Upstream Object refers to your upstream API/service sitting behind Kong Gateway, to which client requests are forwarded. In Kong Gateway, an Upstream Object represents a virtual hostname and can be used to health check, circuit break, and load balance incoming requests over multiple services (targets).

In this topic, you’ll configure the service created earlier (example_service) to point to an upstream instead of the host. For the purposes of our example, the upstream will point to two different targets, httpbin.konghq.com and httpbun.com. In a real environment, the upstream will point to the same service running on multiple systems.

Here is a diagram illustrating the setup:

Upstream targets

Why load balance across upstream targets?

In the following example, you’ll use an application deployed across two different servers, or upstream targets. Kong Gateway needs to load balance across both servers, so that if one of the servers is unavailable, it automatically detects the problem and routes all traffic to the working server.

Configure Upstream Services

In this section, you will create an Upstream named example_upstream and add two targets to it.

Using Kong Manager

Using the Admin API

Using decK (YAML)

Access your Kong Manager instance and your default workspace.
Go to API Gateway > Upstreams.
Click New Upstream.
For this example, enter example_upstream in the Name field.
Scroll down and click Create.
On the Upstreams page, find the new upstream service and click View.
Scroll down and click New Target.
In the target field, specify httpbin.konghq.com with port 80, and click Create.
Create another target, this time for httpbun.com with port 80. Click Create.
Open the Services page.
Find your example_service and click Edit.
Change the Host field to example_upstream, then click Update.

Call the Admin API on port 8001 and create an Upstream named example_upstream:

      cURL
    

      HTTPie
    
curl -X POST http://localhost:8001/upstreams \
  --data name=example_upstream
http POST :8001/upstreams \
  name=example_upstream

Update the service you created previously to point to this upstream:

      cURL
    

      HTTPie
    
curl -X PATCH http://localhost:8001/services/example_service \
  --data host='example_upstream'
http PATCH :8001/services/example_service \
  host='example_upstream'

Add two targets to the upstream, each with port 80: httpbun.com:80 and httpbin.konghq.com:80:

      cURL
    

      HTTPie
    
curl -X POST http://localhost:8001/upstreams/example_upstream/targets \
  --data target='httpbun.com:80'

curl -X POST http://localhost:8001/upstreams/example_upstream/targets \
  --data target='httpbin.konghq.com:80'
http POST :8001/upstreams/example_upstream/targets \
  target=httpbun.com:80
http POST :8001/upstreams/example_upstream/targets \
  target=httpbin.konghq.com:80

In your kong.yaml file, create an Upstream with two targets, each with port 80: httpbun.com:80 and httpbin.konghq.com:80.

 upstreams:
 - name: example_upstream
   targets:
     - target: httpbin.konghq.com:80
       weight: 100
     - target: httpbun.com:80
       weight: 100

Update the service you created previously, pointing the host to this Upstream:

 services:
   host: example_upstream
   name: example_service
   port: 80
   protocol: http

After these updates, your file should now look like this:

 _format_version: "1.1"
 services:
 - host: example_upstream
   name: example_service
   port: 80
   protocol: http
   routes:
   - name: mocking
     paths:
     - /mock
     strip_path: true
     plugins:
     - name: key-auth
       enabled: false
 consumers:
 - custom_id: consumer
   username: consumer
   keyauth_credentials:
   - key: apikey
 upstreams:
 - name: example_upstream
   targets:
     - target: httpbin.konghq.com:80
       weight: 100
     - target: httpbun.com:80
       weight: 100
 plugins:
 - name: rate-limiting
   config:
     minute: 5
     policy: local
 - name: proxy-cache
   config:
     content_type:
     - "application/json; charset=utf-8"
     cache_ttl: 30
     strategy: memory

Sync the configuration:
```
 deck sync
```

You now have an Upstream with two targets, httpbin.konghq.com and httpbun.com, and a service pointing to that Upstream.

Validate the Upstream Services

With the Upstream configured, validate that it’s working by visiting the route http://localhost:8000/mock using a web browser or CLI.
Continue hitting the endpoint and the site should change from httpbin to httpbin.

Summary and next steps

In this topic, you:

Created an Upstream object named example_upstream and pointed the Service example_service to it.
Added two targets, httpbin.konghq.com and httpbun.com, with equal weight to the Upstream.

If you have a Kong Konnect subscription, go on to Managing Administrative Teams.