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Health Checks UI automatic Kubernetes services discovery

HealthChecks UI supports automatic discovery of k8s services exposing pods that have health checks endpoints. This means, you can benefit from it and avoid registering all the endpoints you want to check and let the UI discover them using the k8s api.

k8s-discovery

The default mechanism to register the target endpoints to be queried for health is using the UI project appsettings.json and declare our named endpoints:

Example:

{
  "HealthChecksUI": {
    "HealthChecks": [
      {
        "Name": "Http and UI on single project",
        "Uri": "http://localhost:6001/healthz"
      }
    ],
    "Webhooks": [],
    "EvaluationTimeOnSeconds": 10,
    "MinimumSecondsBetweenFailureNotifications": 60
  }
}

To enable Kubernetes discovery you just need to configure some settings inside the UI project appsettings.json:

{
  "HealthChecksUI": {
    "KubernetesDiscoveryService": {
          "Enabled": true,
          "ClusterHost": "https://myaks-962d02ba.hcp.westeurope.azmk8s.io:443",
          "Token": "eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.eyJpc3M...",      
          "HealthPath": "healthz"      
    }
  }
}

Parameters description

Here are all the available parameters detailed:

Parameter Description Default Value
Enabled Establishes if the k8s discovery service is enabled of disabled false
ClusterHost The uri of the kubernetes cluster
Token The token that will be sent to the cluster for authentication
HealthPath The url path where the UI will call once the service is discovered hc
ServicesLabel The labeled services the UI will look for in k8s HealtChecks
RefreshTimeOnSeconds Healthchecks refresh time in seconds 300

Labeling Services for discovery in Kubernetes

The ServicesLabel option provided in the discovery settings (by default HealthChecks) is the label that will be used to filter k8s services.

If you want to tag a service just execute the k8s command line tool (kubectl) using the following command:

kubectl label service service-name HealthChecks=true

Change HealthChecks=true by your configured ServiceLabel if you gave another value for it.

How it works

The kubernetes service discovery will retrieve from the k8s api all the labelled services and from the metadata it will try to build the target url to query for health.

If you have exposed a deployment using for example a LoadBalancer on port 50000 and your configured HealthPath is "healthz" the target url to be queried would be : (ip/host):50000/healthz

NOTE: Remember if you are using kubectl proxy you can configure your cluster address as http://localhost:8001.