Istio Multicluster Examples

This is a set of demo/example scripts demonstrating how to setup various forms of Istio multicluster connectivity and/or enable multicluster for existing Istio installations.

Prerequisites/requirements:

• Two Kubernetes clusters with admin RBAC credentials granted to the current user. Credentials need to be fetched and available in a form of one single or two separate kubeconfig files. Those steps are cloud provider specific, most likely you will want to use default kubeconfig file and obtain names of cluster contexts for corresponding cluster from the output of kubectl config get-contexts command.
• The following tools need to be available in the PATH (somewhat varies depending on which example you want to use):
  • bash
  • kubectl
  • helm
  • curl
  • sed
  • openssl (N/A at the moment -- example certs are currently hardcoded)

Usage:

Make sure prerequisites are met, have the names of corresponding kubeconfig files and/or context names handy, run one or more executable scripts passing the arguments in a form of environment variables (listed on top of each script).

Example:

$ ISTIO_VERTION=1.1.3 \
  KUBECONTEXT1=gke_istio-test-230101_us-central1-a_mc-vpn-c1 \
  KUBECONTEXT2=gke_istio-test-230101_us-central1-a_mc-vpn-c2 \
  ./vpn.sh

Available Istio builds (i.e. values for ISTIO_VERSION) can be found here:

• https://gcsweb.istio.io/gcs/istio-release/releases/
• https://gcsweb.istio.io/gcs/istio-prerelease/daily-build/

For more details refer to the corresponding sections of Istio documentation:

• https://istio.io/docs/concepts/multicluster-deployments/
• https://istio.io/docs/setup/kubernetes/install/multicluster/
• https://istio.io/docs/examples/multicluster/

Table of contents:

Script name	Description
vpn.sh	Spins up two fresh Istio installations with that are using VPN connectivity mode
gateway.sh	Spins up two fresh Istio installations demonstrating how a remote service from another cluster can be called via a multicluster gateway connectivity mode
disconnected.sh	Sping up two disconnected Istio installation in order to use them with retrofit.sh
retrofit.sh	Demonstrates how to join two existing disconnected Istio installations into a multicluster mesh using VPN connectivity mode