AWS Auto Scaling: Breaking it down

AWS Auto Scaling: Breaking it down
By Jay Smith / on 25 Aug, 2023

AWS Auto Scaling allows you to automatically scale your application across multiple AWS services like EC2, DynamoDB, and Aurora. It provides a simple interface to optimize resource utilization and performance.

Key capabilities:

  • Application scaling across services

  • Manage and optimize cloud resources

  • Maintain performance and availability

  • Predictive scaling based on demand forecasts

  • Cost optimization - pay only for required capacity

  • Flexibility and ease of setup

With Auto Scaling, you can ensure your application has the right amount of resources to maintain optimal performance at the lowest possible cost.

Key Components of Auto Scaling

There are several key components that make up the Auto Scaling service:

Auto Scaling Groups (ASGs)

  • Logical pools of resources like EC2 instances

  • Defined with min, max, desired capacity

  • Launches/terminates instances based on demand

Launch Configurations

  • Template that defines an EC2 instance

  • Specifies AMI, instance type, key pair, security groups, etc.

Launch Templates

  • Newer way to configure instances

  • Supports versioning, multiple instance types

  • More advanced features than launch configs

Scaling Policies

Rules that define when/how to scale ASG

Types:

  • Target tracking - scale based on metric

  • Step scaling - scale in/out in increments

  • Simple scaling - scale by set adjustment

  • Scheduled - scale on schedule

  • Predictive - scale based on forecasts

With these core components, Auto Scaling provides a flexible and automated way to manage scaling events. By defining ASGs, launch configs/templates and scaling policies, you can ensure optimal performance and cost efficiency.

How Auto Scaling Works

Auto Scaling dynamically adjusts capacity by performing scale out and scale in events:

Scale Out

Adds capacity to the ASG. Triggered by:

  • Manual capacity increase

  • Scaling policy threshold breached

  • Scheduled scaling event

When a scale out event occurs, the ASG launches new instances using the launch config/template.

Scale In

Removes capacity from the ASG by terminating instances. Triggered by:

  • Manual capacity decrease

  • Scaling policy threshold breached

  • Scheduled scaling event

Maintaining Performance

Auto Scaling ensures optimal performance and availability using:

  • Target tracking policies to maintain utilization levels

  • Predictive scaling to forecast demand changes

  • Automatically replace failed instances

  • Distribute traffic via load balancing

Advanced Features

  • Lifecycle hooks to perform actions during scale events

  • Integration with other AWS services like SQS -Notifications on scaling events

Auto Scaling provides automated and efficient management of resources. By leveraging features like predictive scaling, lifecycle hooks, and load balancing, Auto Scaling can maintain high performance and availability as demand fluctuates.

IV. Benefits of Using Auto Scaling

Auto Scaling provides many benefits:

Flexibility and Ease of Setup

  • Unified interface to scale multiple resources

  • Automatic discovery of scalable resources

  • Predefined strategies to optimize for performance or cost

  • Quickly view utilization and scale resources across services

  • Fully managed - automatically creates scaling policies

Auto Scaling makes it easy to get started and manage scaling with minimal effort.

Cost Optimization

  • Scale resource capacity up or down to precisely meet demand

  • Predictive scaling provisions the right capacity in advance

  • Only pay for the resources you need

  • Reduce costs by leveraging Spot instances

Auto Scaling enables you to maximize utilization and only pay for the capacity you require.

Automation and Efficiency

  • Maintain performance by automatically scaling capacity

  • Replace failed instances without manual intervention

  • Forecast demand and proactively scale

  • Automatically scale a variety of resources like EC2, DynamoDB, Aurora

  • Streamline and automate scaling workflows

By handling scalability efficiently and automatically, Auto Scaling allows you to focus on your applications rather than infrastructure management.

High Availability

  • Minimize downtime by automatically replacing failed instances

  • Distribute traffic via load balancing integration

  • Provide excess capacity for fault tolerance

  • Smoothly handle spikes in traffic or load

Auto Scaling keeps your applications highly available and resilient to changes in demand.

Auto Scaling for EC2

Auto Scaling is commonly used to scale EC2 capacity:

Fleet Management

Auto Scaling manages EC2 instances as a fleet and performs actions like:

  • Automatically replace failed instances

  • Distribute instances across availability zones

  • Integrate with load balancers

  • Manage health checks and instance lifecycle

This provides resilience and high availability.

Dynamic and Predictive Scaling

Auto Scaling allows you to:

  • Scale EC2s based on metrics like CPU utilization

  • Define automatic scaling policies to react to changes

Types of scaling policies:

  • Target tracking

  • Step scaling

  • Simple scaling

  • Leverage predictive scaling to forecast demand

  • Schedule scaling events on a regular basis

Optimizing Cost Efficiency

  • Pay-per-use pricing of EC2s

  • Combine EC2 On-Demand, Reserved and Spot Instances

  • Leverage Spot and Reserved pricing with auto scaling

  • Purchase Savings Plans for additional discounts

  • Scale instances down when not needed to stop hourly charges

  • Analyze Spend with tools like Cost Explorer

Auto Scaling for EC2 enables both performance optimization and cost efficiency.

Additional Auto Scaling Services

Beyond EC2, Auto Scaling supports:

Application Auto Scaling

Scales other AWS resource types:

  • Amazon ECS services

  • AWS Fargate tasks

  • Amazon DynamoDB throughput capacity

  • Aurora Replicas

  • Amazon SQS queue throughput

  • Custom resources from AWS Lambda

Application Auto Scaling provides granular scaling for individual resources.

Amazon EC2 Auto Scaling

  • Focussed specifically on EC2 instances

  • Provides advanced fleet management capabilities

Integrates with EC2 purchasing options:

  • On-Demand Instances

  • Reserved Instances

  • Savings Plans

  • Spot Instances

AWS Auto Scaling

Unified service that includes:

  • Application Auto Scaling

  • Amazon EC2 Auto Scaling

  • Features like automatic discovery, strategies, predictive scaling

Provides a central interface to scale both EC2 and other AWS resource types.

Integrations

Other services Auto Scaling integrates with:

  • Amazon CloudWatch - for monitoring and alarms

  • AWS Lambda - run code in response to scaling activities

  • Amazon SNS - notifications on scaling events

  • AWS CloudTrail - track API calls and events

Best Practices

To optimize Auto Scaling, follow these best practices:

Defining Scaling Policies

  • Choose metrics with 1 minute frequency for fast scaling

  • Set policies based on business needs and technical limits

  • Evaluate different policy types like target tracking and step scaling

  • Test policies in “forecast only” mode before automated scaling

  • Add scale-in policies to match scale-out events

Properly configured policies ensure scaling occurs when truly needed.

Monitoring and Notifications

  • Review CloudWatch alarms and metrics regularly

  • Enable ASG notifications for scale events via SNS

  • Monitor billing and usage with Cost Explorer

  • Use instance status checks and ELB health checks

  • Tag instances for easier tracking

Monitoring provides visibility into scaling activities.

Performance Optimization

  • Use detailed monitoring for 1 minute metrics

  • Distribute instances across availability zones

  • Ensure enough capacity to handle traffic spikes

  • Pre-warm instances using predictive scaling

  • Load test your architecture and tune ASG limits

Performance testing aids in sizing and configuring for peak efficiency.

Cost Optimization

  • Use EC2 reservation discounts and savings plans

  • Combine On-Demand, Reserved, Spot, and Savings Plans

  • Scale in/out based on demand patterns

  • Right size instances based on actual usage

  • Use EC2 instance scheduling to stop instances

  • Analyze spend and configure budgets

Continuously evaluate and optimize costs as needs change.

Auto Scaling Configuration

Key steps to configure Auto Scaling:

Create Launch Template

Defines the configuration for instances. Specifies:

  • AMI

  • Instance type

  • Storage

  • Security groups

  • Purchase options (on-demand, spot, reserved)

  • Network settings

  • Monitoring settings

  • Tags

Launch templates support versioning and multiple instance types.

Configure Auto Scaling Group

Defines the scale-out settings:

  • Name

  • Launch template or configuration

  • VPC and subnets

  • Load balancers

  • Min, max, desired capacity

  • Scaling policies

  • Health checks

  • Notifications and tags

Launch and configure resources based on rules.

Add Load Balancing (Optional)

  • Create Elastic Load Balancer

  • Attach ASG to ELB

  • ELB distributes traffic across ASG instances

  • Supports high availability and fault tolerance

Define Scaling Policies

Rules that trigger scale out/in events:

  • Target tracking policies

  • Step scaling policies

  • Simple scaling policies

  • Scheduled actions

Automatically adjust capacity based on demand.

Test and Configure

  • Simulate load to test performance

  • Monitor metrics and tune ASG

  • Adjust policies based on actual data

  • Enable detailed monitoring

  • Tag resources and set notifications

Use Cases

Common Auto Scaling use cases:

Unpredictable/Fluctuating Workloads

  • Applications with variable traffic patterns

  • Maintain performance during traffic spikes

  • Reduce costs during low-traffic periods

  • Leverage predictive scaling to forecast demand

  • Automatically scale based on metrics like CPU utilization

Auto Scaling shines for workloads with unpredictable usage.

High Availability Applications

  • Automatically replace failed instances

  • Distribute instances across availability zones

  • Integrate with load balancers

  • Ensure additional capacity for failover

  • Minimize downtime through redundancy

Critical applications benefit from Auto Scaling’s reliability capabilities.

Leveraging Spot Instances

  • Reduce costs by using EC2 Spot instances

  • Predict Spot interruptions and rebalance load

  • Replace interrupted Spot Instances automatically

  • Combine Spot, On-Demand and Reserved instances

Smartly leverage Spot along with other purchase options.

Optimizing Costs

  • Pay based on actual usage by scaling dynamically

  • Schedule ASG to follow usage patterns

  • Leverage Reserved Instance discounts

  • Right-size instances to needs

  • Use Savings Plans for additional discounts

  • Analyze spend and configure budgets

Optimize costs by scaling usage precisely to current demand.

Conclusion

In summary, AWS Auto Scaling is a robust and fully-managed service to dynamically scale capacity across various resources. By automatically launching or terminating instances based on demand, Auto Scaling maintains high performance, availability, and efficient infrastructure utilization. Auto Scaling streamlines infrastructure management through automation, allowing you to focus on your applications and optimize costs. With capabilities like predictive scaling, flexible instance management, and automated workload provisioning, Auto Scaling is a powerful tool for workloads of all types.

Here are 10 Frequently Asked Questions and Answers using markdown formatting and incorporating LSI keywords:

Frequently Asked Questions

What is AWS Auto Scaling?

AWS Auto Scaling allows you to automatically scale your resources and EC2 capacity up or down based on demand. It helps maintain optimal performance and availability while optimizing costs.

What are the benefits of Auto Scaling?

Key benefits include:

  • Achieve high availability and performance

  • Automatic scaling to precisely meet demand

  • Optimize costs by using only needed capacity

  • Easy to set up and manage

  • Predictive scaling to forecast demand changes

What AWS resources can I scale with Auto Scaling?

You can use Auto Scaling to dynamically scale:

  • EC2 instances

  • DynamoDB capacity

  • Aurora replicas

  • ECS services

  • Custom resources via AWS Lambda

How does Auto Scaling work?

It works by performing scale out and scale in events automatically based on metrics, utilization, and scaling policies. This maintains optimal capacity as demand fluctuates.

What are Auto Scaling Groups (ASGs)?

ASGs are logical pools of resources like EC2 instances that can be scaled together. ASGs are defined with min, max, and desired capacity.

How do I get started with Auto Scaling?

Key steps are:

  1. Create a launch template

  2. Define an ASG

  3. Add optional scaling policies

  4. Test performance and configure

What are the best practices for Auto Scaling?

Best practices include:

  • Choose fast 1 minute metrics

  • Test scaling policies before automated use

  • Distribute instances across availability zones

  • Monitor metrics, set alarms, and enable notifications

How can I optimize costs with Auto Scaling?

Cost optimization tips:

  • Scale based on demand patterns

  • Use EC2 Reserved Instance discounts

  • Combine instance types (On-Demand, Reserved, Spot)

  • Analyze spend and configure budgets

Does Auto Scaling work with Spot Instances?

Yes, you can use EC2 Auto Scaling to leverage Spot Instances. Features like predictive rebalancing help manage Spot interruptions.

What is Predictive Scaling?

Predictive Scaling uses ML to forecast demand changes. It automatically scales capacity in advance based on predicted metrics.