curl -sSL https://gist.githubusercontent.com/drnic/9c5f2d58865c8595fe3aa77672f3ebc8/raw/cf7b10072da392c07257ee33367f3daab2d484d7/k3sup-gce.sh | bash -s up

k3sup-gce.sh

#!/bin/bash

set -u

up() {
    INSTANCE_TYPE=${INSTANCE_TYPE:-n1-standard-1}

    (
    set -x
    gcloud compute instances create k3s-1 \
        --machine-type  "$INSTANCE_TYPE" \
        --tags k3s,k3s-master

    gcloud compute instances create k3s-2 k3s-3 \
        --machine-type  "$INSTANCE_TYPE" \
        --tags k3s,k3s-worker

    gcloud compute config-ssh
    )

    primary_server_ip=$(gcloud compute instances list \
    --filter=tags.items=k3s-master \
    --format="get(networkInterfaces[0].accessConfigs.natIP)")

    (
    set -x
    k3sup install --ip "${primary_server_ip}" --context k3s --ssh-key ~/.ssh/google_compute_engine --user $(whoami)

    gcloud compute firewall-rules create k3s --allow=tcp:6443 --target-tags=k3s

    gcloud compute instances list \
        --filter=tags.items=k3s-worker \
        --format="get(networkInterfaces[0].accessConfigs.natIP)" | \
            xargs -L1 k3sup join \
            --server-ip $primary_server_ip \
            --ssh-key ~/.ssh/google_compute_engine \
            --user $(whoami) \
            --ip
    )

    export KUBECONFIG=`pwd`/kubeconfig
    kubectl get nodes
}

down() {
    set -x
    gcloud compute instances list \
        --filter=tags.items=k3s --format="get(name)" | \
            xargs gcloud compute instances delete -q

    gcloud compute firewall-rules delete k3s
}

usage() {
    echo "Bootstrap or tear down a k3s cluster on GCE"
    echo "  up"
    echo "  down"
}

case "${1:-usage}" in
  up)
    shift
    up "$@"
    ;;
  down)
    shift
    down "$@"
    ;;
  *)
    usage
    exit 1
    ;;
esac

In the latest gcloud version, you need to specify the zone. Thanks for the gist, it is pretty handy.