gce-centos-k8s/scripts/0_env_setup.sh

#!/bin/bash
##
## Script to set up the kubernetes on Google Cloud environment settings
##
main () {
echo "This script will create a file .gce_kubernetes.config in the current directory that
will contain the variables that you are about to set to set up the Kubernetes cluster on 
Google Compute Engine. You should also have already authenticated to the Google Cloud via
the gcloud command line interface."
  
  if [ -f .gce_kubernetes.config ]; then
    read -p "Kubernetes configuration file exists. Do you wish to display the contents? [y]" show_config
    show_config=${show_config:-y}
      if [ "$show_config" == "y" ]; then
        cat .gce_kubernetes.config
        read -p "Do you wish to set up the configuration again? [n]" reset_config
        reset_config=${reset_config:-n}
        if [ "$reset_config" == "n" ]; then
          echo "Exiting"
        else
          config_gather
        fi
      else
        echo "Setting up the configuration ..."
        config_gather
      fi
  else
    echo "Setting up the configuration ..."
    config_gather
  fi 
}

config_gather () {
  read -p "Please enter the Google Compute Region you want to use? [us-west1]" gce_region
  gce_region=${gce_region:-us-west1}
  read -p "Please enter the Google Compute Zone you want to use? [us-west1-c]" gce_zone
  gce_zone=${gce_zone:-us-west1-c}
  read -p "Please enter the Google Compute Project you are going to use? (This should already exist)" gce_project

  read -p "What version of Kubernetes do you want to install? Tested versions: 1.10.3, 1.10.5, and [1.10.6]"
  kube_ver=${kube_ver:-1.10.6}  

  read -p "Please enter the name of GCE network you want to create? [kubernetes]" kube_network
  kube_network=${kube_network:-kubernetes}
  read -p "Please enter the name of the GCE subnet within the $kube_network you want to create? [kubernetes-subnet]" kube_subnet
  kube_subnet=${kube_subnet:-kubernetes-subnet}
  read -p "Please enter the name used for the public IP address object in Google Compute? [kube-public-ip]" kube_pub_ip
  kube_pub_ip=${kube_pub_ip:-kube-public-ip}
  read -p "Please enter the CIDR network address range of the kubernetes subnet? [10.240.0.0/24]" kube_subnet_cidr
  kube_subnet_cidr=${kube_subnet_cidr:-10.240.0.0/24}
  kube_subnet_addr_calc=`ipcalc -n $kube_subnet_cidr | cut -c 9- | rev | cut -c 3- | rev`
  read -p "Please enter the lowest network component of the IP address range [$kube_subnet_addr_calc]?" kube_subnet_addr
  kube_subnet_addr=${kube_subnet_addr:-$kube_subnet_addr_calc}
  read -p "Please enter the pod CIDR network address to be used? [10.200.0.0/16]" kube_pod_cidr
  kube_pod_cidr=${kube_pod_cidr:-10.200.0.0/16}
  kube_pod_addr_calc=`ipcalc -n $kube_pod_cidr | cut -c 9- | rev | cut -c 5- | rev`
  read -p "Please enter the lowest network component of the pod address range [$kube_pod_addr_calc]?" kube_pod_addr
  kube_pod_addr=${kube_pod_addr:-$kube_pod_addr_calc}
  kube_pod_cidr_prefix=`echo $kube_pod_cidr | rev| cut -c -2 | rev`
  kube_pod_node_prefix=$(($kube_pod_cidr_prefix + 8))
  read -p "Best guess at the CIDR prefix used on the nodes for the pod subnets [$kube_pod_node_prefix]" kube_node_pod_prefix
  kube_node_pod_prefix=${kube_node_pod_prefix:-$kube_pod_node_prefix}
  read -p "Firewall rules will be created for internal traffic (all allowed) and external traffic (ssh, ping, kubernetes).
  You can provide a name for the internal traffic rule: [kubernetes-allow-internal]" kube_int_fw_name
  kube_int_fw_name=${kube_int_fw_name:-kubernetes-allow-internal}
  read -p "  You can provide a name for the external traffic rule: [kubernetes-allow-external]" kube_ext_fw_name
  kube_ext_fw_name=${kube_ext_fw_name:-kubernetes-allow-external}
  read -p "Please enter the name used for the Kubernetes Cluster object? [kube-cluster]" kube_cluster
  kube_cluster=${kube_cluster:-kube-cluster}
  read -p "How many master (controller) nodes in the Kubernetes cluster do you want to create (currently a maximum of 9)? [2]" kube_masters
  kube_masters=${kube_masters:-2}
  read -p "How many worker nodes in the Kubernetes cluster do you want to create (currently a maximum of 9)? [2]" kube_workers
  kube_workers=${kube_workers:-2}

  echo "The following variables will be committed to the configuration file:
  GCE region:                               $gce_region
  GCE zone:                                 $gce_zone
  GCE project:                              $gce_project
  Kubernetes Version:                       $kube_ver
  GCE VPC network name:                     $kube_network
  GCE VPC subnet name:                      $kube_subnet
  Kubernetes public IP address object name: $kube_pub_ip
  Kubernetes subnet CIDR address:           $kube_subnet_cidr
  Kubernetes subnet address:                $kube_subnet_addr
  Kubernetes pod subnet CIDR address:       $kube_pod_cidr
  Kubernetes pod address:                   $kube_pod_addr
  Kubernetes node pod CIDR prefix:          $kube_node_pod_prefix
  Kubernetes internal firewall rule:        $kube_int_fw_name
  Kubernetes external firewall rule:        $kube_ext_fw_name
  Kubernetes cluster object name:           $kube_cluster
  Number of controller nodes:               $kube_masters
  Number of worker nodes:                   $kube_workers"

  read -p "Please confirm that these values are correct (y/n) [y]" confirm_values
  confirm_values=${confirm_values:-y}

  if [ "$confirm_values" == "y" ]; then
    cat > .gce_kubernetes.config << EOM
GCE_REGION=$gce_region
GCE_ZONE=$gce_zone
GCE_PROJECT=$gce_project
KUBE_VER=$kube_ver
KUBE_NETWORK=$kube_network
KUBE_SUBNET=$kube_subnet
KUBE_PUB_IP=$kube_pub_ip
KUBE_SUBNET_CIDR=$kube_subnet_cidr
KUBE_SUBNET_ADDR=$kube_subnet_addr
KUBE_POD_CIDR=$kube_pod_cidr
KUBE_POD_ADDR=$kube_pod_addr
KUBE_NODE_POD_PREFIX=$kube_node_pod_prefix
KUBE_INT_FW_NAME=$kube_int_fw_name
KUBE_EXT_FW_NAME=$kube_ext_fw_name
KUBE_CLUSTER=$kube_cluster
KUBE_CONTROLLERS=$kube_masters
KUBE_WORKERS=$kube_workers
EOM
  fi
}

main