Bootstrap k8s clusters on RPi

k8s_pi_bootstrap.sh

#!/bin/bash
# Usage
# Kubernetes master node
# sudo k8s_pi_bootstrap.sh master
#
# Kubernetes worker node
# sudo k8s_pi_bootstrap.sh worker cluster_token master_ip

download_kubeadm () {
  is_kubeadm_installed
  if [[ $? == 0 ]]; then
    echo 'Kubeadm already installed'
  else
    echo 'Downloading kubeadm'
    # trust the kubernetes APT key and add the official APT Kubernetes repository
    curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -
    echo "deb http://apt.kubernetes.io/ kubernetes-xenial main" > /etc/apt/sources.list.d/kubernetes.list
    apt-get update && apt-get install -y kubeadm
  fi
}

is_kubeadm_installed () {
  kubeadm version
}

kubeadmin () {
  if [[ $(is_kubeadm_installed) == 0 ]]; then
    echo 'Kubeadm already installed'
  else
    apt-get update && apt-get install -y kubeadm
  fi
}

initialize_master_node () {
  echo 'Initalizing master node'
  # 10.244.0.0/16
  # Default pod CIDR 10.244.0.0/16
  if [[ -z "$1" ]]; then
    CIDR="10.244.0.0/16"
  else
    CIDR=$1
  fi
  echo "Pod CIDR $CIDR"
  kubeadm init \
    --pod-network-cidr $CIDR \
    --api-external-dns-names=kube-pi.builtbyexp.com \
    --use-kubernetes-version 'v1.5.1'

  set_up_flannel_network
}

set_up_flannel_network () {
  curl -sSL https://rawgit.com/coreos/flannel/master/Documentation/kube-flannel.yml | sed "s/amd64/arm/g" | kubectl create -f -
}

deploy_k8s_dashboard () {
  # Downloading and installing k8s dashboard
  echo 'Installing k8s dashboard'
  curl -sSL https://rawgit.com/kubernetes/dashboard/master/src/deploy/kubernetes-dashboard.yaml | sed "s/amd64/arm/g" | kubectl create -f -

  # create NodePort service for dashboard
  echo 'Creating NodePort k8s service for dashboard'
  kubectl -n kube-system get service kubernetes-dashboard -o template --template="{{ (index .spec.ports 0).nodePort }}" | xargs echo
}

initialize_worker_node () {
  echo 'Initalizing worker with:'
  echo "Token: $1"
  echo "Master IP: $2"

  kubeadm join --token=$1 $2
}

reset_node () {
  # reseting node and cleaning up
  echo 'Reseting node and cleaning up'
  kubeadm reset
  etcdctl rm --recursive registry
  rm -rf /var/lib/cni
  rm -rf /run/flannel
  rm -rf /etc/cni on master and nodes
  ifconfig cni0 down
  brctl delbr cni0
}

# start
download_kubeadm

if [[ $1 == 'master' ]]; then
  initialize_master_node
elif [[ $1 == 'worker' ]]; then
  initialize_worker_node $2 $3
elif [[ $1 == 'reset' ]]; then
  reset_node
else
  echo "Options are 'master' or 'worker' "
fi