berylcc/k8s-custom-iptables repository overview

⁠k8s-custom-iptables Helm chart

A Helm chart to help with adding custom IP tables rules to nodes in a Kubernetes cluster. This collection of scripts and templates create a NAT (MASQ) rule for outbound traffic to a TARGETS CIDR range(s) given to the script.

This is only necessary on Google Container Engine (GKE) if your cluster isn't a VPC-native cluster using alias IP address ranges. For more information see: https://cloud.google.com/kubernetes-engine/docs/how-to/alias-ips⁠

Helm chart based on https://v3.helm.sh/docs/topics/chart_repository/#github-pages-example⁠ and https://github.com/technosophos/tscharts⁠.

Kubernetes templates and scripts based on https://github.com/bowei/k8s-custom-iptables⁠

⁠Repo URL

https://team-blaze.github.io/helm-k8s-custom-iptables⁠

⁠Configuration

The following table lists the configurable parameters of the k8s-custom-iptables chart and their default values, and can be overwritten via the helm --set flag.

You'll definitely need to update the nat_ip_ranges to match the ones in your cloud VPC. In my case that was finding out the IP of the database – say 10.146.11.3 – and then defining a reasonable CIDR range which would include it – say 10.146.11.0/24.

I've pushed the image built off the Dockerfile in this repo into a public repo under my personal Docker Hub account which will work, but you should push into and use your private cloud registry. If you do so, you'll need to set imagePullSecrets for Kubernetes to be authenticated to pull the image when deploying, see: https://kubernetes.io/docs/tasks/configure-pod-container/pull-image-private-registry/⁠

⁠TODO

• Add a way to clear IP tables when removing chart based on https://github.com/bowei/k8s-custom-iptables/blob/master/uninstall.sh⁠