The health endpoint

Document updated on May 2, 2021

If you place a balancer in front of KrakenD, such as an ELB, you can check KrakenD health using a TCP port check. If, on the other hand, you need an HTTP endpoint in systems like Kubernetes, use the internal endpoint /__health.

The /__health endpoint

The health endpoint, or the ping endpoint, works without any specific configuration as KrakenD automatically adds it.

For instance, see the simplest possible krakend.json:

$cat krakend.json
{ "version: 2 }

Start this server and query the /__health endpoint. You’ll have a 200 response code from KrakenD with the following content:

$curl http://localhost:8080/__health
{"status":"OK"}

Custom alternatives to the health endpoint

If, for any reason, you don’t want to use the /__health endpoint and its content and want to have your custom response, the simplest solution is to use stub data to alter the response.

A custom health configuration could look like this:

    {
        "version": 2,
        "port": 8080,
        "endpoints": [
        {
            "endpoint": "/health",
            "extra_config": {
                "github.com/devopsfaith/krakend/proxy": {
                    "static": {
                    "data": {
                        "custom": "response",
                        "foo": "bar"
                    },
                    "strategy": "always"
                    }
                }
            },
            "backend": [
            {
                "url_pattern": "/__health",
                "host": [
                    "http://localhost:8080"
                ]
            }
            ]
        }
        ]
    }

In this configuration, KrakenD connects to itself, but instead of returning the content of the internal health endpoint, it sets the data defined in the static structure. Notice that the listening port in the configuration and the host match your deployed KrakenD.

The response content of this custom /health endpoint is:

$curl http://localhost:8080/health
{"custom": "response","foo": "bar"}