unable to access a service from another pod, using xmlhttprequest object

问题

So, I wrote an API that is listening on the the path /api/v1/books and is deployed as a deployment on my k8s cluster, created service (restapi-service) so that we can call that from another pods. Now I created another deployment (restapi-ui-deployment) that just has a .html page and and its being deployed on nginx, which eventually calls the the service that we have created earlier to get the response. Now, the issue is when I exec into the pods of restapi-ui-deployment I am successfully able to curl http://restapi-service:8081/api/v1/books. But if we are trying to do the same thing from .html page that is deployed I get

GET http://restapi-service:8081/api/v1/books net::ERR_NAME_NOT_RESOLVED

Below is the code that is being deployed as restapi-ui-deployment

if (xmlObj != null){
      xmlObj.open("GET", "http://restapi-service:8081/api/v1/books", true)
      xmlObj.onreadystatechange = processResponse;
      xmlObj.send(null)
    }
    else{
      console.log("There was an error getting the object.")
    }
    function processResponse(){
      if (xmlObj.status == 200 && xmlObj.readyState == 4){
        console.log("Got the response successfully")
        response = xmlObj.responseText
      }
      else{
        console.log("There was an issue getting the response.")
      }
    }

回答1:

I am afraid that you are confused about the way your application works. The XmlHttpRequest is originating in a webbrowser, therefore outside of the kubernetes cluster, not from nginx inside your cluster. (nginx serves the html page) The kubernetes dns is not available outside of kubernetes, nor would a connection to a ClusterIP work from the outside. Solution: Create an appropriate Ingress and call that from your frontend or provide a proxy on your nginx where you got the frontend delivered. (That would lead to really getting the request origin as your nginx)

来源：https://stackoverflow.com/questions/57348029/unable-to-access-a-service-from-another-pod-using-xmlhttprequest-object

标签

Kubernetes

kubernetes-service