GKE Cluster routing internet traffic through basic NAT

This set of scripts creates a Google Cloud Container Engine cluster that routes all outbound internet traffic. Traffic heading for the kubernetes master is routed at a higher priority through the default internet gateway. through a NAT instance.

How it works in a nutshell

1. Creates a network
2. Creates a subnet for the cluster
3. Creates a subnet for the nat instance
4. Creates a NAT compute instance
5. Creates Firewall rules for NAT instance
6. Creates the GKE cluster in the cluster's subnet created from step 2 with tag route-through-nat
7. Creates the route from the cluster to the master for instances with tag, route-through-nat
8. Creates the NAT route from the cluster to the NAT for all destinations at a lower priority than the master route above for instances with tag route-through-nat

Creating the cluster

Prerequisites

1. Updated gcloud sdk
2. Updated kubectl cli
3. A Project in Google Cloud in which you want to deploy this cluster
4. Authenticated to google cloud

Creating the network, subnets, nat, routes, firewall rules and gke cluster

$ git clone https://www.github.com/johnlabarge/gke-nat-example.git
$ cd gke-nat-example
$ ./create

This also runs a quick test for you by

1. installing curl on the machine
2. curling a well known website
3. copying the captured traffic (tcpdump) logs from the Nat computer to the local directory.

Deleting the Cluster

Deleting the network, subnets, nat, routes, firewall rules and gke cluster

$ ./delete