localkube (running only in http mode) throws healthcheck errors

[kmova]

BUG REPORT

Environment:

minikube version: v0.25.0

OS:
  NAME="Ubuntu"
  VERSION="16.04.3 LTS (Xenial Xerus)"
  ID=ubuntu
  ID_LIKE=debian
  PRETTY_NAME="Ubuntu 16.04.3 LTS"
  VERSION_ID="16.04"
  HOME_URL="http://www.ubuntu.com/"
  SUPPORT_URL="http://help.ubuntu.com/"
  BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
  VERSION_CODENAME=xenial
  UBUNTU_CODENAME=xenial
VM driver:
  "DriverName": "none",

What happened:
I had a kubernetes cluster that uses insecure deployment (https://kubernetes.io/docs/getting-started-guides/scratch/#security-models), where API server is exposed via http. (No SSL). Some of the operator pods, that were using client-go, InClusterConfig option to communicate with the API server started failing. I wanted to reproduce this environment using minikube (vm-driver=none) so that I could test my changes to the operator without having to recreate the entire setup -- kubernetes the hardway!

Localkube has setting that can be used to apiserver in insecure(http) mode, using the following options:

--apiserver-insecure-address=0.0.0.0 
--apiserver-insecure-port=8080 
--apiserver-port=0 
--generate-kubeconfig=true

When the above changes are made and localkube is restarted, it starts to continuously throw the following error messages and also doesn;t schedule any pods:

Feb  2 09:53:10 kmova-minikube localkube[2570]: I0202 09:53:10.425450    2570 ready.go:30] Performing healthcheck on http://localhost:0/healthz
Feb  2 09:53:10 kmova-minikube localkube[2570]: E0202 09:53:10.425837    2570 ready.go:40] Error performing healthcheck: Get http://localhost:0/healthz: dial tcp 127.0.0.1:0: getsockopt: connection refused

What you expected to happen:
localkube should be functional in insecure only mode and user should be able to run their workloads.

How to reproduce it (as minimally and precisely as possible):

• Start the minikube by following the instructions at https://github.com/kubernetes/minikube for the option of vm-driver=none.
• Update /etc/systemd/system/localkube.service with the above mentioned insecure options.
• Check the /var/log/syslog

Output of minikube logs (if applicable):

Anything else do we need to know:

The issue is related to the way pkg/localkube/apiserver.go uses the APIServerPort.

 func readyFunc(lk LocalkubeServer) HealthCheck {
        return healthCheck(lk.GetAPIServerProtocol()+path.Join(
               net.JoinHostPort("localhost", strconv.Itoa(lk.APIServerPort)), "healthz"), lk)
 }

Even when APIServerPort is set to 0 via the options, health check is performed on the same port.

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