b-3-n/k8s-custom-iptables

How to add custom iptables rules to a Kubernetes cluster

k8s-custom-iptables

An example of how to add custom IP tables rules to a Kubernetes cluster. This collection of scripts creates a NAT (MASQ) rule for outbound traffic to a TARGETS CIDR range(s) given to the script.

Installing rules into the cluster.

Install the daemonset that configures the cluster to NAT an IP range.

TARGETS="1.2.3.4/24 4.5.6.7/16" ./install.sh

Uninstall rules from the cluster.

Uninstall the IP tables rules from the cluster.

./uninstall.sh

Configuring

The configuration for which ranges are NAT'd are in the k8s-custom-iptables ConfigMap. Values can be changed via kubectl edit cm/k8s-custom-iptables:

apiVersion: v1
kind: ConfigMap
metadata:
  name: k8s-custom-iptables
data:
  nat.rules: "10.0.0.0/24 192.168.0.0/16"

Creating and pushing the image.

REGISTRY=gcr.io/my-registry make