Part-72: To Create a Zonal MIG's and Implement a Regional External Load balancer in GCP Cloud

#googlecloud #devops #learning #cloud

Create a Zonal Managed Instance Group (MIGs)

In Google Cloud Platform (GCP), a Managed Instance Group (MIG) is a collection of identical virtual machine (VM) instances managed as a single entity.

When we say zonal managed instance group, it means:

The instances in the group are all created within a single zone (e.g., us-central1-a).
The group is tied to that zone, so all resources (VMs, disks, etc.) belong there.
If that zone has an outage, all VMs in the MIG will be affected.

Step-01: Introduction

Create Regional Health check
Create Firewall rule
Create Instance Template
Create Zonal Managed Instance Group

Step-02: Create Regional Health Check - TCP

# Create Regional Health Check
gcloud compute health-checks create tcp regional-tcp-health-check \
  --port=80 \
  --region=us-central1

Step-03: Create Firewwall Rules

# Firewall Rule-1: 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

Step-04: Create Instance Template

Make ensure the nginx-webserver.sh file should available in Gcloud shell

#!/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.htm

Create a Instance Template

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

Step-05: Create Zonal Managed Instance Groups

# Zone: us-central1-a: Create Managed Instance Groups in the Zone
gcloud compute instance-groups managed create zmig-us-1 \
    --zone us-central1-a \
    --size 2 \
    --template it-rlbdemo-us-central1 

# Zone: us-central1-c: Create Managed Instance Groups in the Zone
gcloud compute instance-groups managed create zmig-us-2 \
    --zone us-central1-c \
    --size 2 \
    --template it-rlbdemo-us-central1

Create a Google Cloud - Regional Application Load Balancer HTTP

Step-01: Introduction

Pre-requisite-1: Create Instance Templates, Create Managed Instance Groups - We created already
Create Regional Application Load Balancer - HTTP

Step-02: Pre-requisite-2: Reserve proxy-only subnet exclusively for regional load balancing proxies.

Goto VPC Networks -> vpc3-custom -> SUBNETS -> ADD SUBNET
Name: lb-subnet-proxyonly-us-central1
Description: lb-subnet-proxyonly-us-central1
Region: us-central1
Purpose: Regional Managed Proxy
Role: Active
IPv4 Range: 10.129.0.0/23
Click on ADD

Step-03: Pre-requisite-3: Create Firewall rule

fw-allow-proxy-only-subnet: An ingress rule that allows connections from the proxy-only subnet to reach the backends.

# Firewall Rule: Allow connections from Proxy Only Subnets for All Instances in the network
gcloud compute firewall-rules create vpc3-custom-allow-proxy-only-subnet \
    --network=vpc3-custom \
    --action=allow \
    --direction=ingress \
    --source-ranges=10.129.0.0/23 \
    --rules=tcp:80,tcp:443,tcp:8080

Step-04: Pre-requisite-4: Create Regional Health Check - HTTP

# Create Regional Health Check
gcloud compute health-checks create http regional-http-health-check --port=80 --region=us-central1

Step-05: Create Regional Application Load Balancer - HTTP

Go to Network Services -> Load Balancing -> CREATE LOAD BALANCER
Select Application Load Balancer (HTTP/S): START CONFIGURATION
Internet facing or internal only: From Internet to my VMs or serverless services
Global or Regional: Regional external Application Load Balancer
Load Balancer name: regional-lb-external-http
Region: us-central1
Network: vpc3-custom

Frontend Configuration

Click on ADD FRONTEND IP AND PORT
Name: frontend-http
Description: frontend-http
Protocol: HTTP
IP Version: IPv4
IP Address: regional-lb-ip1 CREATE NEW EXTERNAL STATCI IP
Port: 80
Click on DONE

Backend Configuration

CLick on CREATE A BACKEND SERVICE
Name: regional-mybackend-svc1
Description: regional-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: zmig-us-1
Port Numbers: 80
REST ALL LEAVE TO DEFAULTS
Click on DONE
Instance Group: zmig-us-2
Port Numbers: 80
REST ALL LEAVE TO DEFAULTS
Click on DONE