This script triggers and monitors an ASG refresh.

asg_refresh.sh

#!/bin/bash

ASG_NAME=$1
region=$2
profile=$3

export AWS_DEFAULT_REGION=$region
export AWS_PROFILE=$profile


# Start instance refresh with MinHealthyPercentage=100,InstanceWarmup=30
INSTANCE_REFRESH=$(aws autoscaling start-instance-refresh \
    --auto-scaling-group-name $ASG_NAME \
    --preferences MinHealthyPercentage=100,InstanceWarmup=30 \
    --strategy Rolling \
    --query "InstanceRefreshId" --output text)

echo "Started instance refresh with ID: $INSTANCE_REFRESH"

# Monitor instance refresh until refresh Status is Successful
while true; do
    REFRESH_STATUS=$(aws autoscaling describe-instance-refreshes \
        --auto-scaling-group-name $ASG_NAME \
        --query "InstanceRefreshes[?InstanceRefreshId=='$INSTANCE_REFRESH'].Status[]" --output text)

    if [ "$REFRESH_STATUS" == "Successful" ]; then
        echo "Instance refresh completed successfully"
        exit 0
    elif [ "$REFRESH_STATUS" == "Cancelled" ] || [ "$REFRESH_STATUS" == "Failed" ]; then
        echo "Instance refresh failed or was cancelled"
        exit 1
    else
        REFRESH_INFO=$(aws autoscaling describe-instance-refreshes \
            --auto-scaling-group-name $ASG_NAME \
            --query "InstanceRefreshes[?InstanceRefreshId=='$INSTANCE_REFRESH'].[PercentageComplete,Status,StatusReason]" --output text)
        echo "Instance refresh status: $REFRESH_INFO"        
    fi

    sleep 30
done

unset AWS_DEFAULT_REGION
unset AWS_PROFILE