Create a K3s cluster very quickly in Hezner cloud

create-k3s-cluster.sh

#!/bin/bash

POSITIONAL=()
while [[ $# -gt 0 ]]
do
key="$1"

case $key in
  --context)
    CONTEXT_NAME="$2"
    shift # past argument
    shift # past value
  ;;
  --kubeconfig-path)
    KUBECONFIG_PATH="$2"
    shift # past argument
    shift # past value
  ;;
  --token)
    TOKEN="$2"
    shift # past argument
    shift # past value
  ;;
  --master)
    MASTER="$2"
    shift
    shift
  ;;
  --workers)
    IFS=','
    read -ra WORKERS <<<"$2"
    shift
    shift
  ;;
  --flannel-interface)
    FLANNEL_INTERFACE="$2"
    shift
    shift
  ;;
  --cluster-cidr)
    FLANNEL_INTERFACE="$2"
    shift
    shift
  ;;
  --ssh-user)
    SSH_USER="$2"
    shift
    shift
  ;;
  *)
    POSITIONAL+=("$1")
    shift
  ;;
esac
done
set -- "${POSITIONAL[@]}" # restore positional parameters

[[ -z "$CONTEXT_NAME" ]] && { echo "Please specify the context name with '--context <name>'" ; exit 1; }

[[ -z "$KUBECONFIG_PATH" ]] && { echo "Please specify the path where to save the kubeconfig with '--kubeconfig-path <path>'" ; exit 1; }

[[ -z "$TOKEN" ]] && { echo "Please specify the token with '--token <token>'" ; exit 1; }

[[ -z "$MASTER" ]] && { echo "Please specify the public ip of the master with '--master <public-ip1>,<public-ip2>,...'" ; exit 1; }

[[ -z "$FLANNEL_INTERFACE" ]] && { echo "Please specify the Flannel interface with '--flannel-interface <interfacce>'" ; exit 1; }

if [ ${#WORKERS[@]} -eq 0 ]; then
    echo "Please specify one or more workers with '--workers <public-ip>'"
    exit 1
fi

CLUSTER_CIDR=${CLUSTER_CIDR:-"10.244.0.0/16"}
SSH_USER=${SSH_USER:-"root"}

MASTER_PRIVATE_IP=$(ssh $SSH_USER@$MASTER "hostname -I" | awk '{print $2}')

  cat << EOF > /tmp/master.sh
  FLANNEL_INTERFACE="$FLANNEL_INTERFACE"
  CLUSTER_CIDR="$CLUSTER_CIDR"
K3S_TOKEN="$TOKEN"
EOF

  cat << 'EOF' >> /tmp/master.sh
  curl -sfL https://get.k3s.io | K3S_TOKEN=$K3S_TOKEN INSTALL_K3S_EXEC="server \
    --disable-cloud-controller \
    --disable servicelb \
    --disable traefik \
    --disable local-storage \
    --write-kubeconfig-mode=644 \
    --node-name="$(hostname -f)" \
    --cluster-cidr=$CLUSTER_CIDR \
    --tls-san=$(hostname -I | awk '{print $1}') \
    --kubelet-arg="cloud-provider=external" \
    --node-ip=$(hostname -I | awk '{print $2}') \
    --node-external-ip=$(hostname -I | awk '{print $1}') \
    --flannel-iface=$FLANNEL_INTERFACE" sh -
EOF

echo
echo "Setting up master..."

scp /tmp/master.sh $SSH_USER@$MASTER:/tmp/master.sh > /dev/null 2>&1
ssh $SSH_USER@$MASTER /bin/bash /tmp/master.sh
echo "...master up and running."

ssh $SSH_USER@$MASTER "cat /etc/rancher/k3s/k3s.yaml" | sed "s/default/$CONTEXT_NAME/g" | sed "s/127.0.0.1/$MASTER/g" > $KUBECONFIG_PATH



for WORKER in "${WORKERS[@]}"
do
  :
  cat << EOF > /tmp/worker.sh
  MASTER_PRIVATE_IP="$MASTER_PRIVATE_IP"
  FLANNEL_INTERFACE="$FLANNEL_INTERFACE"
  CLUSTER_CIDR="$CLUSTER_CIDR"
  K3S_TOKEN="$TOKEN"
EOF

  cat << 'EOF' >> /tmp/worker.sh
  curl -sfL https://get.k3s.io | K3S_TOKEN=$K3S_TOKEN K3S_URL=https://$MASTER_PRIVATE_IP:6443 INSTALL_K3S_EXEC="agent \
    --node-name="$(hostname -f)" \
    --kubelet-arg="cloud-provider=external" \
    --node-ip=$(hostname -I | awk '{print $2}') \
    --node-external-ip=$(hostname -I | awk '{print $1}') \
    --flannel-iface=$FLANNEL_INTERFACE" sh -
EOF

  echo
  echo "Setting up worker on $WORKER..."

  scp /tmp/worker.sh $SSH_USER@$WORKER:/tmp/worker.sh > /dev/null 2>&1
  ssh $SSH_USER@$WORKER /bin/bash /tmp/worker.sh
  echo "...worker $WORKER up and running."

  echo

done

echo
echo "Finished building k3s cluster."