Auto Scaling Multiple Instance Types

Auto Scaling is a fundamental feature of Amazon EC2 that allows you to automatically adjust the number of EC2 instances in your application based on demand. This lesson focuses on how to implement Auto Scaling for multiple instance types, giving you flexibility and cost efficiency.

2.1. Auto Scaling Group

An Auto Scaling Group (ASG) is a collection of EC2 instances that are managed together. You can define scaling policies to add or remove instances based on CloudWatch metrics.

2.2. Launch Configuration

A Launch Configuration is an instance configuration template that an ASG uses to launch EC2 instances. It defines instance type, AMI, key pair, security groups, and block storage.

2.3. Instance Types

AWS provides various instance types optimized for different use cases. When using multiple instance types, you can balance performance and cost more effectively.

3.1. Create a Launch Template

Create a launch template that specifies multiple instance types.

aws ec2 create-launch-template \
    --launch-template-name MyLaunchTemplate \
    --version-description Version1 \
    --launch-template-data '{
        "instanceType": "t2.micro",
        "imageId": "ami-0abcdef1234567890",
        "instanceMarketOptions": {
            "marketType": "spot"
        }
    }'
        

3.2. Create an Auto Scaling Group

Use the launch template to create an Auto Scaling Group.

aws autoscaling create-auto-scaling-group \
    --auto-scaling-group-name MyAutoScalingGroup \
    --launch-template "LaunchTemplateName=MyLaunchTemplate,Version=1" \
    --min-size 1 \
    --max-size 10 \
    --desired-capacity 3 \
    --vpc-zone-identifier "subnet-0bb1c79de3EXAMPLE"
        

3.3. Set Scaling Policies

Define scaling policies to manage instance scaling.

aws autoscaling put-scaling-policy \
    --auto-scaling-group-name MyAutoScalingGroup \
    --policy-name ScaleOut \
    --scaling-adjustment 1 \
    --adjustment-type ChangeInCapacity
        

• Use a mix of instance types to optimize performance.
• Set up health checks to replace unhealthy instances automatically.
• Consider using Spot Instances to reduce costs.
• Test your Auto Scaling configuration regularly to ensure it meets your application needs.