Creates a http/https load balancer in GCE using provided parameters

create-multi-region-l7-lb.sh

#! /bin/bash

# sourced from https://gist.github.com/bprashanth/3827059fc46cba4ffbe1651ee3e9a78f#gistcomment-1828832
show_usage() {
  echo ""
  echo -e "Usage: $0 balancer-name \"ig1,ig1_zone;ig2,ig2_zone[;ig3...]\" project static-ip hc-path port certname"
  echo ""
  echo "List manage instance groups: gcloud compute instance-groups managed list"
  echo "List project global IPs: gcloud compute addresses list --global --project $PROJECT"
  echo "Reserve a new IP: gcloud compute addresses create <name> --global --project $PROJECT"
  echo "List certificates: gcloud compute ssl-certificates list"
}
function check_jq {
  which jq 2>&1 > /dev/null
  local havejq=$?
  if [ $havejq -ne 0 ]; then
    echo
    echo "==============================================================="
    echo "jq required but not found - please install jq (brew install jq)"
    echo "==============================================================="
    echo
    exit 1
  fi
}

if [ $# -ne 7 ]
then
  show_usage
  exit 1
fi
# Name of the app as "app-env, i.e. blm-dev, blm-qa"
APP=$1
# The instance group(s) of the associated GKE cluster
IGS=$2
# project of GKE cluster
PROJECT=$3
# This static ip must already exist. It's used to create the forwarding rule.
STATIC_IP=$4
# This path must serve a 200 on </path> for UA (GoogleHC/1.0)
HEALTH_CHECK_PATH=$5
# NodePort of the Kubernetes service.
# kubectl get svc ${SVC} -o yaml | grep -i nodeport
# or
# kubectl get svc ${SVC} --template='{{range $i, $n := .spec.ports}}{{$n.nodePort}} {{end}}'
SVC_NODE_PORT=$6
# This certificate must already exist.
CERTNAME=$7


#function join_by { local IFS="$1"; shift; echo "$*"; }
#dink=$(join_by , "${pairs[@]}")
#echo $dink
#exit

function debug {
echo
echo APP is $APP
echo IGS is $IGS
echo PROJECT is $PROJECT
echo STATIC_IP is $STATIC_IP
echo HEALTH_CHECK_PATH is $HEALTH_CHECK_PATH
echo SVC_NODE_PORT is $SVC_NODE_PORT
echo CERTNAME is $CERTNAME
echo
}
# uncomment this to print variables
#debug

IFS=';' read -ra K8S_MIGS <<< "$IGS"

declare K8S_MIGS[]
function createl7 {
echo "# Create the firewall rule to allow health check traffic from LB pool"
echo gcloud compute --project $PROJECT firewall-rules create allow-l7-$1 --source-ranges 130.211.0.0/22 --allow tcp:$1
echo
for IG in ${K8S_MIGS[@]}; do
  IFS=',' read -ra PAIR <<< "$IG"
  echo "# Append the named port ($APP-$1) on ${PAIR[0]}"
  declare -a pairs
  read -ra pairs <<< $(gcloud compute instance-groups get-named-ports ${PAIR[0]} --zone ${PAIR[1]} --format json | jq -j '.[] | "\(.name):\(.port),"')
  echo gcloud compute --project $PROJECT instance-groups set-named-ports ${PAIR[0]} --zone ${PAIR[1]} --named-ports ${pairs}$APP-$1:$1
  echo
done
echo "# Create the health check"
echo gcloud compute --project $PROJECT http-health-checks create "$APP-hc-$1" --port $1 --request-path "$HEALTH_CHECK_PATH"
echo
echo "# Create the backend service, using health check $APP-hc-$1"
echo gcloud compute --project $PROJECT backend-services create "$APP-be-$1" --port-name $APP-$1 --protocol "HTTP" --http-health-checks "$APP-hc-$1"
echo
for IG in ${K8S_MIGS[@]}; do
  IFS=',' read -ra BE <<< "$IG"
  echo "# Add the instance group \"${BE[0]}\" in ${BE[1]} to the backend service"
  echo gcloud compute --project $PROJECT backend-services add-backend "$APP-be-$1" --instance-group-zone ${BE[1]} --balancing-mode "UTILIZATION" --instance-group ${BE[0]}
  echo
done
echo "# Create the url map"
echo gcloud compute --project $PROJECT url-maps create "$APP-lb" --default-service "$APP-be-$1"
echo
echo "# Create the http proxy"
echo gcloud compute --project $PROJECT target-http-proxies create "$APP-$1-http" --url-map "$APP-lb"
echo
echo "# Create the https proxy"
echo gcloud compute --project $PROJECT target-https-proxies create "$APP-$1-https" --ssl-certificate $CERTNAME --url-map "$APP-lb"
echo
echo "# Create the http forwarding rule"
echo gcloud compute forwarding-rules create $APP-$1-http --target-http-proxy=$APP-$1-http --address $STATIC_IP --ports=80 --global
echo
echo "# Create the https forwarding rule"
echo gcloud compute forwarding-rules create $APP-$1-https --target-https-proxy=$APP-$1-https --address $STATIC_IP --ports=443 --global
echo
}
check_jq
createl7 $SVC_NODE_PORT