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Using ExternalName in Kubernetes Cluster to Map DataKit Service¶

Introduction¶

In a Kubernetes cluster, after deploying DataKit as a DaemonSet, if an application previously pushed trace data to the zipkin service in the istio-system namespace on port 9411, i.e., the access address was zipkin.istio-system.svc.cluster.local:9411.

What if you do not want to change the push address? This is where the ExternalName service type of Kubernetes comes into play. By following these two steps, the application can be connected to DataKit:

First, define a ClusterIP service type to map port 9529 to 9411.
Second, use an ExternalName service to map the ClusterIP service to a DNS name.

1 Define the ClusterIP Service¶

apiVersion: v1
kind: Service
metadata:
  name: datakit-service-ext
  namespace: datakit
spec:
  selector:
    app: daemonset-datakit
  ports:
    - protocol: TCP
      port: 9411
      targetPort: 9529

After deployment, containers within the cluster can access DataKit's port 9529 using datakit-service-ext.datakit.svc.cluster.local:9411.

2 Define the ExternalName Service¶

apiVersion: v1
kind: Service
metadata:
  name: zipkin
  namespace: istio-system
spec:
  type: ExternalName
  externalName: datakit-service-ext.datakit.svc.cluster.local

After deployment, containers within the cluster can push data to DataKit using zipkin.istio-system.svc.cluster.local:9411.