port-forwards should not allocate system ports

[briandealwis]

Our port-forwarding handling for services requests the same local port as the service port:

skaffold/pkg/skaffold/kubernetes/portforward/resource_forwarder.go

Line 144 in 66fe1c7

LocalPort: int(p.Port),

On Windows systems, where system ports can be allocated by ordinary processes, this means that a service can allocate ports 80 or 443 which is generally not desirable. This issue is not normally seen on *nix systems as allocating system ports require running as root.

This can lead to puzzling behaviour as Skaffold's port-forwards listen only on localhost, which allows co-existing with another process that listens on IP_ADDRANY on the same port (such as the k8s cluster's ingress port!).

As a workaround, users can set up explicit port-forwards for the corresponding services.

Information

• Operating system: Windows

Steps to reproduce the behavior

1. Alter Skaffold's example/typescript's k8s/deployment.yaml to use port 80
2. skaffold dev --port-forward
3. See Skaffold port-forward to port 80

[alisters]

Thanks for raising this and the speedy change. This, along with the helm debugging support you've added over time will bring us close to "git pull, skaffold run" across a set of disparate enterprise services and charts. Much appreciated.