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Cover image for Part-67: 🌍 Mastering Google Cloud Global Load Balancers: Regional MIG + Global HTTP Demo
Latchu@DevOps
Latchu@DevOps

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Part-67: 🌍 Mastering Google Cloud Global Load Balancers: Regional MIG + Global HTTP Demo

#googlecloud #devops #cloud #learning

Google Cloud - Regional Managed Instance Groups

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Step-01: Introduction

i. Creatre VPC: vpc3-custom
ii. Create Firewall Ingress Rules

  • Allow ICMP
  • Allow SSH 22
  • Allow all ip, all ports between VM instances in a VPC network
  • Allows traffic from the Google Cloud health checking systems (130.211.0.0/22 and 35.191.0.0/16)

iii. Create two subnets in two regions

  • us-central1-subnet
  • us-east1-subnet

iv. Create Instance Template in us-central1, us-east1 regions
v. Create Global Health check (applicable for both us-east1 and us central1 regions)
vi. Create Managed Instance Groups in us-central1, us-east1 regions

  • Create Managed Instance Group (MIG)
  • Create Named port for MIG

Step-02: Create VPC Network

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# Set Project
gcloud config set project PROJECT_ID
gcloud config set project gcpdemos

# Create VPC Network
gcloud compute networks create vpc3-custom --subnet-mode=custom --bgp-routing-mode=global
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Step-03: Create VPC Firewall Rules

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# Firewall Rule-1: Allows ICMP connections from any source to any instance on the network
gcloud compute firewall-rules create vpc3-custom-allow-icmp \
  --network=vpc3-custom \
  --description=Allows\ ICMP\ connections\ from\ any\ source\ to\ any\ instance\ on\ the\ network \
  --direction=INGRESS \
  --priority=65534 \
  --source-ranges=0.0.0.0/0 \
  --action=ALLOW \
  --rules=icmp

# Firewall Rule-2: Allows TCP connections from any source to any instance on the network using port 22.
gcloud compute firewall-rules create vpc3-custom-allow-ssh \
  --network=vpc3-custom \
  --description=Allows\ TCP\ connections\ from\ any\ source\ to\ any\ instance\ on\ the\ network\ using\ port\ 22. \
  --direction=INGRESS \
  --priority=65534 \
  --source-ranges=0.0.0.0/0 \
  --action=ALLOW \
  --rules=tcp:22 

# (OPTIONAL) Firewall Rule-3: Allows connection from any source to any instance on the network using custom protocols
gcloud compute firewall-rules create vpc3-custom-allow-custom \
  --network=vpc3-custom \
  --description=Allows\ connection\ from\ any\ source\ to\ any\ instance\ on\ the\ network\ using\ custom\ protocols. \
  --direction=INGRESS \
  --priority=65534 \
  --source-ranges=10.128.0.0/9 \
  --action=ALLOW \
  --rules=all   

# Firewall Rule-4: Ingress rule that allows traffic from the Google Cloud health checking systems (130.211.0.0/22 and 35.191.0.0/16).
gcloud compute firewall-rules create vpc3-custom-allow-health-check \
  --network=vpc3-custom \
  --description=Allows\ traffic\ from\ Google\ Cloud\ health\ checking\ systems \
  --direction=ingress \
  --source-ranges=130.211.0.0/22,35.191.0.0/16 \
  --action=allow \
  --rules=tcp:80
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Step-04: Create Subnets

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# Subnet1: Create Subnet in us-central1 region 
gcloud compute networks subnets create us-central1-subnet \
  --description=us-central1-subnet \
  --range=10.135.0.0/20 \
  --stack-type=IPV4_ONLY \
  --network=vpc3-custom \
  --region=us-central1

# Subnet2: Create Subnet in us-east1 region
gcloud compute networks subnets create us-east1-subnet \
  --description=us-east1-subnet \
  --range=10.145.0.0/20 \
  --stack-type=IPV4_ONLY \
  --network=vpc3-custom \
  --region=us-east1
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Step-05: Create Health Check - Global

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# Create health check - global
gcloud compute health-checks create http global-http-health-check --port 80
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Step-06: Review Startup Script

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#!/bin/bash
sudo apt install -y telnet
sudo apt install -y nginx
sudo systemctl enable nginx
sudo chmod -R 755 /var/www/html
HOSTNAME=$(hostname)
sudo echo "<!DOCTYPE html> <html> <body style='background-color:rgb(250, 210, 210);'> <h1>Welcome to Latchu@DevOps - WebVM App1 </h1> <p><strong>VM Hostname:</strong> $HOSTNAME</p> <p><strong>VM IP Address:</strong> $(hostname -I)</p> <p><strong>Application Version:</strong> V1</p> <p>Google Cloud Platform - Demos</p> </body></html>" | sudo tee /var/www/html/index.html
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Make ensure this nginx-webserver.sh file should be available in GCloud Shell

Step-07: us-central1: Create Instance Template and Managed Instance Group

  • Important Note:

i. Upload nginx-webserver.sh to Google Cloud shell if running gcloud commands on cloud shell
ii. Ensure nginx-webserver.sh is present in the current directory where you are running this gcloud command

  • Create Instance Template
  • Create Managed Instance Group

i. Create Managed Instance Group (MIG)
ii. Create Named port for MIG

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# 1. us-central1: Create Instance Template
gcloud compute instance-templates create it-lbdemo-us-central1 \
   --region=us-central1 \
   --network=vpc3-custom \
   --subnet=us-central1-subnet \
   --machine-type=e2-micro \
   --metadata-from-file=startup-script=nginx-webserver.sh

# 2. Create the managed instance group and select the instance template.
gcloud compute instance-groups managed create mig1-us-central1 \
    --template=it-lbdemo-us-central1 \
    --size=2 \
    --zones=us-central1-b,us-central1-c \
    --health-check=global-http-health-check

# 3. Add a named port to the instance group
gcloud compute instance-groups set-named-ports mig1-us-central1 \
    --named-ports webserver80:80 \
    --region us-central1
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Step-04: us-east1: Create Instance Template and Managed Instance Group

  • Create Instance Template
  • Create Managed Instance Group

i. Create Managed Instance Group (MIG)
ii. Create Named port for MIG

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# 1. us-east1: Create Instance Template
gcloud compute instance-templates create it-lbdemo-us-east1 \
   --region=us-east1 \
   --network=vpc3-custom \
   --subnet=us-east1-subnet \
   --machine-type=e2-micro \
   --metadata-from-file=startup-script=nginx-webserver.sh 

# 2. us-east1: Create the managed instance group and select the instance template.
gcloud compute instance-groups managed create mig2-us-east1 \
    --template=it-lbdemo-us-east1 \
    --size=2 \
    --zones=us-east1-c,us-east1-d \
    --health-check=global-http-health-check

# 3. us-east1: Add a named port to the instance group
gcloud compute instance-groups set-named-ports mig2-us-east1 \
    --named-ports webserver80:80 \
    --region us-east1
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Step-05: Verify the following resources

  1. VPC
  2. Subnets
  3. Firewalls
  4. Health Checks
  5. Instance Templates
  6. Managed Instance Groups

Cloud Load Balancing - Application Load Balancer (HTTP/S)

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  • Application Load Balancer (HTTP/S)
  • Proxy-based Layer 7 load balancers
  • Proxy-based means - Client traffic terminated on Load Balancer and new Connection created from load balancer to backends

  • Provides - content-based routing and Application-aware health checks

  • External & Internal

Global - support backends in multiple regions
Regional - support backends in a single region only
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  • Accessibility 
External: Accessible via internet
Internal: Accessible to systems in VPC or systems connected to VPC
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  • Ideal for web applications, APIs and microservices

Global External Application Load balancer HTTP

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Implement a Google Cloud - Global External Application Load Balancer HTTP

Step-01: Introduction

Pre-requisite-1: Create Instance Templates, Create Managed Instance Groups as we created in first stage
Create Global Application Load Balancer - HTTP

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Step-02: Create Global HTTP Load Balancer

Application Load Balancer (HTTP/S)

  1. Go to Network Services -> Load Balancing -> CREATE LOAD BALANCER
  2. Select Application Load Balancer (HTTP/S): START CONFIGURATION
  3. Internet facing or internal only: From Internet to my VMs or serverless services
  4. Global or Regional: Global external Application Load Balancer
  5. Click on CONTINUE
  6. Load Balancer name: global-lb-external-http

Frontend Configuration

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  1. Click on ADD FRONTEND IP AND PORT
  2. Name: frontend-http
  3. Description: frontend-http
  4. Protocol: HTTP
  5. IP Version: IPv4
  6. IP Address: global-lb-ip1 CREATE NEW EXTERNAL STATCI IP
  7. Port: 80
  8. Click on DONE

Backend Configuration

  • CLick on CREATE A BACKEND SERVICE
  • Name: mybackend-svc1
  • Description: mybackend-svc1
  • Backend type: Instance Group
  • Protocol: HTTP
  • Named Port: webserver80 (AUTO-POPULATED WHEN BACKEND IS SELECTED AS mig1-lbdemo)
  • Timeout: 30
  • BACKENDS 
Instance Group: mig1-us-central1
Port Numbers: 80
REST ALL LEAVE TO DEFAULTS
Click on DONE
Instance Group: mig1-us-east1
Port Numbers: 80
REST ALL LEAVE TO DEFAULTS
Click on DONE
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  • Disable Cloud CDN
  • Health Check: http-health-check
  • Security: 
Cloud Armor backend security policy: NONE
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  • Click on CREATE

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Routing Rules

  • Mode: Simple host and path rule
  • REST ALL LEAVE TO DEFAULTS

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Review and Finalize

  • Review all settings
  • Click on CREATE

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Step-03: Verify Load Balancer

  • Go to Network Services -> Load Balancing -> global-lb-external-http
  • Review the Tabs 
LOAD BALANCERS
BACKENDS
FRONTENDS
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Step-04: Access Application using LB IP on browser

Important Note: WAIT FOR 3 to 5 Minutes before Load Balancer is fully operational

# Access Application
http://LB-IP
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Step-05: Test multi-region functionality (Send traffic to region closest to client)

To simulate a user in a different geography, you can connect to one of your virtual machine instances in a different region, and then run a curl command from that instance to see the request go to an instance in the region closest to it.

# Set Project
gcloud config set project PROJECT_ID
gcloud config set project gcpdemos

# Region: us-central1
gcloud compute ssh --zone "us-central1-c" "mig1-us-central1-xq12" 
curl http://LB-IP
curl http://34.36.49.82/

# Region: us-east1
gcloud compute ssh --zone "us-east1-d" "mig2-us-east1-693l" 
curl http://LB-IP
curl http://34.36.49.82/
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Step-06: Delete Load Balancer

  • Delete the Load balancer created as part of this demo.
  • Don't delete Backend services as we need to use in upcoming demo

🌟 Thanks for reading! If this post added value, a like ❤️, follow, or share would encourage me to keep creating more content.

— Latchu | Senior DevOps & Cloud Engineer

☁️ AWS | GCP | ☸️ Kubernetes | 🔐 Security | ⚡ Automation
📌 Sharing hands-on guides, best practices & real-world cloud solutions

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