#!/bin/bash
# AMI Update Helper Scripts for Auto Scaling Groups
# Region: ap-south-1
# Generated: January 22, 2026
set -e
REGION="ap-south-1"
COLOR_GREEN='\033[0;32m'
COLOR_YELLOW='\033[1;33m'
COLOR_RED='\033[0;31m'
COLOR_RESET='\033[0m'
# Function to print colored output
print_info() {
echo -e "${COLOR_GREEN}[INFO]${COLOR_RESET} $1"
}
print_warning() {
echo -e "${COLOR_YELLOW}[WARNING]${COLOR_RESET} $1"
}
print_error() {
echo -e "${COLOR_RED}[ERROR]${COLOR_RESET} $1"
}
# ============================================================================
# 1. Find Latest AMI
# ============================================================================
find_latest_ecs_ami() {
local arch=$1 # x86_64 or arm64
print_info "Finding latest ECS-optimized Amazon Linux 2023 AMI for ${arch}..."
if [ "$arch" == "arm64" ]; then
aws ssm get-parameter \
--name /aws/service/ecs/optimized-ami/amazon-linux-2023/arm64/recommended \
--region $REGION \
--query 'Parameter.Value' \
--output text | jq -r '.image_id, .image_name'
else
aws ssm get-parameter \
--name /aws/service/ecs/optimized-ami/amazon-linux-2023/recommended \
--region $REGION \
--query 'Parameter.Value' \
--output text | jq -r '.image_id, .image_name'
fi
}
find_latest_eks_ami() {
local k8s_version=$1 # e.g., 1.32
local arch=$2 # x86_64 or arm64
print_info "Finding latest EKS-optimized AMI for Kubernetes ${k8s_version} (${arch})..."
aws ssm get-parameter \
--name "/aws/service/eks/optimized-ami/${k8s_version}/amazon-linux-2023/${arch}/recommended" \
--region $REGION \
--query 'Parameter.Value' \
--output text | jq -r '.image_id, .image_name'
}
# ============================================================================
# 2. Get ASG Current Configuration
# ============================================================================
get_asg_info() {
local asg_name=$1
print_info "Getting information for ASG: ${asg_name}"
aws autoscaling describe-auto-scaling-groups \
--auto-scaling-group-names "$asg_name" \
--region $REGION \
--query 'AutoScalingGroups[0].[AutoScalingGroupName,MinSize,MaxSize,DesiredCapacity,LaunchTemplate.LaunchTemplateId,LaunchTemplate.Version]' \
--output table
}
get_current_ami() {
local asg_name=$1
print_info "Getting current AMI for ASG: ${asg_name}"
# Get launch template ID
local lt_id=$(aws autoscaling describe-auto-scaling-groups \
--auto-scaling-group-names "$asg_name" \
--region $REGION \
--query 'AutoScalingGroups[0].LaunchTemplate.LaunchTemplateId' \
--output text)
if [ "$lt_id" == "None" ] || [ -z "$lt_id" ]; then
print_error "No launch template found for ASG: ${asg_name}"
return 1
fi
# Get AMI from launch template
aws ec2 describe-launch-template-versions \
--launch-template-id "$lt_id" \
--versions '$Latest' \
--region $REGION \
--query 'LaunchTemplateVersions[0].[LaunchTemplateId,VersionNumber,LaunchTemplateData.ImageId]' \
--output table
# Get AMI details
local ami_id=$(aws ec2 describe-launch-template-versions \
--launch-template-id "$lt_id" \
--versions '$Latest' \
--region $REGION \
--query 'LaunchTemplateVersions[0].LaunchTemplateData.ImageId' \
--output text)
aws ec2 describe-images \
--image-ids "$ami_id" \
--region $REGION \
--query 'Images[0].[ImageId,Name,CreationDate,Architecture]' \
--output table
}
# ============================================================================
# 3. Update Launch Template
# ============================================================================
update_launch_template() {
local asg_name=$1
local new_ami_id=$2
print_info "Updating launch template for ASG: ${asg_name}"
# Get launch template ID
local lt_id=$(aws autoscaling describe-auto-scaling-groups \
--auto-scaling-group-names "$asg_name" \
--region $REGION \
--query 'AutoScalingGroups[0].LaunchTemplate.LaunchTemplateId' \
--output text)
if [ "$lt_id" == "None" ] || [ -z "$lt_id" ]; then
print_error "No launch template found for ASG: ${asg_name}"
return 1
fi
print_info "Launch Template ID: ${lt_id}"
print_info "New AMI ID: ${new_ami_id}"
# Create new version
print_info "Creating new launch template version..."
aws ec2 create-launch-template-version \
--launch-template-id "$lt_id" \
--source-version '$Latest' \
--launch-template-data "{\"ImageId\":\"${new_ami_id}\"}" \
--region $REGION
# Set as default
print_info "Setting new version as default..."
aws ec2 modify-launch-template \
--launch-template-id "$lt_id" \
--default-version '$Latest' \
--region $REGION
print_info "Launch template updated successfully!"
}
# ============================================================================
# 4. Start Instance Refresh
# ============================================================================
start_instance_refresh() {
local asg_name=$1
local min_healthy_pct=${2:-90}
local warmup=${3:-300}
print_info "Starting instance refresh for ASG: ${asg_name}"
print_warning "Min Healthy Percentage: ${min_healthy_pct}%"
print_warning "Instance Warmup: ${warmup} seconds"
aws autoscaling start-instance-refresh \
--auto-scaling-group-name "$asg_name" \
--preferences "{
\"MinHealthyPercentage\": ${min_healthy_pct},
\"InstanceWarmup\": ${warmup},
\"CheckpointPercentages\": [50, 100],
\"CheckpointDelay\": 300
}" \
--region $REGION
print_info "Instance refresh started! Monitor with: check_refresh_status ${asg_name}"
}
# ============================================================================
# 5. Monitor Instance Refresh
# ============================================================================
check_refresh_status() {
local asg_name=$1
print_info "Checking instance refresh status for ASG: ${asg_name}"
aws autoscaling describe-instance-refreshes \
--auto-scaling-group-name "$asg_name" \
--region $REGION \
--query 'InstanceRefreshes[0].[Status,StatusReason,PercentageComplete,InstancesToUpdate]' \
--output table
}
watch_refresh_status() {
local asg_name=$1
local interval=${2:-30}
print_info "Watching instance refresh for ASG: ${asg_name} (checking every ${interval}s)"
print_warning "Press Ctrl+C to stop watching"
while true; do
clear
echo "=== Instance Refresh Status for ${asg_name} ==="
echo "Time: $(date)"
echo ""
check_refresh_status "$asg_name"
local status=$(aws autoscaling describe-instance-refreshes \
--auto-scaling-group-name "$asg_name" \
--region $REGION \
--query 'InstanceRefreshes[0].Status' \
--output text)
if [ "$status" == "Successful" ]; then
print_info "Instance refresh completed successfully!"
break
elif [ "$status" == "Failed" ] || [ "$status" == "Cancelled" ]; then
print_error "Instance refresh ${status}!"
break
fi
sleep $interval
done
}
# ============================================================================
# 6. Cancel Instance Refresh (Rollback)
# ============================================================================
cancel_instance_refresh() {
local asg_name=$1
print_warning "Cancelling instance refresh for ASG: ${asg_name}"
aws autoscaling cancel-instance-refresh \
--auto-scaling-group-name "$asg_name" \
--region $REGION
print_info "Instance refresh cancelled!"
}
# ============================================================================
# 7. Rollback Launch Template
# ============================================================================
rollback_launch_template() {
local asg_name=$1
local version=${2:-'$Latest-1'}
print_warning "Rolling back launch template for ASG: ${asg_name}"
# Get launch template ID
local lt_id=$(aws autoscaling describe-auto-scaling-groups \
--auto-scaling-group-names "$asg_name" \
--region $REGION \
--query 'AutoScalingGroups[0].LaunchTemplate.LaunchTemplateId' \
--output text)
if [ "$version" == '$Latest-1' ]; then
# Get current version number and subtract 1
local current_version=$(aws ec2 describe-launch-template-versions \
--launch-template-id "$lt_id" \
--versions '$Latest' \
--region $REGION \
--query 'LaunchTemplateVersions[0].VersionNumber' \
--output text)
version=$((current_version - 1))
fi
print_info "Rolling back to version: ${version}"
aws ec2 modify-launch-template \
--launch-template-id "$lt_id" \
--default-version "$version" \
--region $REGION
print_info "Launch template rolled back to version ${version}"
}
# ============================================================================
# 8. Batch Update for Phase 1 (Scaled-to-Zero ASGs)
# ============================================================================
update_phase1_asgs() {
local new_ami_id=$1
if [ -z "$new_ami_id" ]; then
print_error "Please provide new AMI ID"
echo "Usage: update_phase1_asgs <AMI_ID>"
return 1
fi
print_info "Starting Phase 1 updates (scaled-to-zero ASGs)"
print_info "New AMI: ${new_ami_id}"
local asgs=(
"live-bootcamp"
"live-desk-allocation"
"live-newi"
"live-v1-growth"
)
for asg in "${asgs[@]}"; do
print_info "Processing ASG: ${asg}"
update_launch_template "$asg" "$new_ami_id"
echo ""
done
print_info "Phase 1 updates completed!"
}
# ============================================================================
# 9. Full Update Workflow
# ============================================================================
full_update_workflow() {
local asg_name=$1
local new_ami_id=$2
if [ -z "$asg_name" ] || [ -z "$new_ami_id" ]; then
print_error "Missing required parameters"
echo "Usage: full_update_workflow <ASG_NAME> <NEW_AMI_ID>"
return 1
fi
print_info "=== Full Update Workflow for ${asg_name} ==="
echo ""
# Step 1: Show current config
print_info "Step 1: Current Configuration"
get_asg_info "$asg_name"
get_current_ami "$asg_name"
echo ""
# Step 2: Confirm
read -p "Continue with update? (yes/no): " confirm
if [ "$confirm" != "yes" ]; then
print_warning "Update cancelled"
return 0
fi
# Step 3: Update launch template
print_info "Step 2: Updating Launch Template"
update_launch_template "$asg_name" "$new_ami_id"
echo ""
# Step 4: Start instance refresh
print_info "Step 3: Starting Instance Refresh"
start_instance_refresh "$asg_name"
echo ""
# Step 5: Watch progress
print_info "Step 4: Monitoring Progress"
watch_refresh_status "$asg_name"
}
# ============================================================================
# 10. List All ASGs with AMI Info
# ============================================================================
list_all_asgs_with_ami() {
print_info "Listing all ASGs with AMI information..."
local asgs=$(aws autoscaling describe-auto-scaling-groups \
--region $REGION \
--query 'AutoScalingGroups[*].AutoScalingGroupName' \
--output text)
echo "ASG_NAME | AMI_ID | AMI_NAME | AMI_AGE"
echo "---------|--------|----------|--------"
for asg in $asgs; do
local lt_id=$(aws autoscaling describe-auto-scaling-groups \
--auto-scaling-group-names "$asg" \
--region $REGION \
--query 'AutoScalingGroups[0].LaunchTemplate.LaunchTemplateId' \
--output text 2>/dev/null)
if [ "$lt_id" != "None" ] && [ -n "$lt_id" ]; then
local ami_id=$(aws ec2 describe-launch-template-versions \
--launch-template-id "$lt_id" \
--versions '$Latest' \
--region $REGION \
--query 'LaunchTemplateVersions[0].LaunchTemplateData.ImageId' \
--output text 2>/dev/null)
if [ -n "$ami_id" ] && [ "$ami_id" != "None" ]; then
local ami_info=$(aws ec2 describe-images \
--image-ids "$ami_id" \
--region $REGION \
--query 'Images[0].[Name,CreationDate]' \
--output text 2>/dev/null)
echo "${asg} | ${ami_id} | ${ami_info}"
fi
fi
done
}
# ============================================================================
# Usage Examples
# ============================================================================
show_usage() {
cat <<'EOF'
AMI Update Helper Scripts
=========================
Available Functions:
1. Find Latest AMIs:
find_latest_ecs_ami arm64
find_latest_ecs_ami x86_64
find_latest_eks_ami 1.32 arm64
2. Get ASG Information:
get_asg_info <ASG_NAME>
get_current_ami <ASG_NAME>
3. Update Launch Template:
update_launch_template <ASG_NAME> <NEW_AMI_ID>
4. Instance Refresh:
start_instance_refresh <ASG_NAME> [MIN_HEALTHY_PCT] [WARMUP_SECONDS]
check_refresh_status <ASG_NAME>
watch_refresh_status <ASG_NAME> [INTERVAL_SECONDS]
5. Rollback:
cancel_instance_refresh <ASG_NAME>
rollback_launch_template <ASG_NAME> [VERSION]
6. Batch Operations:
update_phase1_asgs <NEW_AMI_ID>
list_all_asgs_with_ami
7. Full Workflow:
full_update_workflow <ASG_NAME> <NEW_AMI_ID>
Examples:
---------
# Find latest ECS AMI for ARM64
find_latest_ecs_ami arm64
# Check current AMI for an ASG
get_current_ami live-ldap
# Update an ASG with new AMI
full_update_workflow live-ldap ami-0123456789abcdef0
# Batch update Phase 1 ASGs
update_phase1_asgs ami-0123456789abcdef0
# Monitor refresh progress
watch_refresh_status live-ldap 30
# Rollback if needed
cancel_instance_refresh live-ldap
rollback_launch_template live-ldap
EOF
}
# ============================================================================
# Main
# ============================================================================
# If script is executed (not sourced), show usage
if [ "${BASH_SOURCE[0]}" = "${0}" ]; then
show_usage
fi
