When using GKE, the kubectl context must be called gke1 for other scripts to work. the gke1.sh script helps with the task.
This script also provision ext-dns which automatically create DNS record based on host setting in Istio Gateway object. This component is optional. A google service account credential JSON file is required for this to work.
# retrieve credential for the new cluster and store locally
./gke1.sh
# do all the above create a new cluster called gke1 the do all the above
./gke1.sh -f