With a standard Kubernetes deployment on Google Container Engine, to include services configured with the Kubernetes load balancer settings which creates network load balancers, is it possible to access the user's (or referring) IP address in an application? In the case of PHP, checking common headers in the $_SERVER superglobal only results in the server and internal network addresses being available.
Not yet. Services go through kube_proxy, which answers the client connection and proxies through to the backend (your PHP server). The address that you'd see would be the IP of whichever kube-proxy the connection went through.
Work has been done, and a tracking issue is still open to switch over to an iptables-only proxy. That would allow your PHP server to get the actual client IP.
来源：https://stackoverflow.com/questions/32723675/gce-k8s-accessing-referral-ip-address