"No endpoints" issue

[justinsb]

We were hitting the "no endpoints for X" issue after upgrading from beta.5 to beta.7.

I think the problem is that there are too many names floating around, but I think that actually ingress has made a mistake here: https://github.com/kubernetes/ingress/blob/master/core/pkg/ingress/controller/controller.go#L840-L848

	for _, servicePort := range svc.Spec.Ports {
		// targetPort could be a string, use the name or the port (int)
		if strconv.Itoa(int(servicePort.Port)) == backendPort ||
			servicePort.TargetPort.String() == backendPort ||
			servicePort.Name == backendPort {

So backendPort is the backendPort of the ingress. We match against the service's exposed port (good), or the service's Name (good) or the service's TargetPort (which I think is wrong, but is not the issue here).

			endps := ic.getEndpoints(svc, servicePort.TargetPort, api.ProtocolTCP, hz)
			if len(endps) == 0 {
				glog.Warningf("service %v does not have any active endpoints", svcKey)
			}

We then get the endpoints using servicePort.TargetPort ... but that is not correct. It should be servicePort.Name, because it is the service port Name that is stored in the Endpoint, not the targetport Name.

https://github.com/kubernetes/kubernetes/blob/master/pkg/api/types.go#L2833-L2835

Also note that there might be no name at all, if the service only defines a single port.

(For the record, I also thought it was the TargetPort in the Endpoint)

[aledbf]

Closing. Fixed in #846