Lab: Auto Scaling Configuration

Lab Objective

Design and configure a complete Auto Scaling solution for a web application with variable traffic patterns.

Part 1: Scenario

Context

NewsPortal is a news site that experiences unpredictable traffic spikes during breaking news. The technical team wants to automate scaling to:

Maintain performance during spikes
Reduce costs during off-peak hours

Traffic Data

┌─────────────────────────────────────────────────────────────┐
│              NEWS PORTAL TRAFFIC PATTERNS                   │
├─────────────────────────────────────────────────────────────┤
│                                                              │
│   NORMAL DAY                                                 │
│   ───────────────                                           │
│                                                              │
│   Visitors ▲                                               │
│            │           ┌────┐                               │
│    50,000 ─┤          ┌┘    └┐                              │
│            │         ┌┘      └┐      ┌──┐                   │
│    30,000 ─┤     ┌──┘        └──────┘  └┐                  │
│            │  ┌──┘                       └──┐               │
│    10,000 ─┤──┘                             └──             │
│            │                                                 │
│            └─────┬─────┬─────┬─────┬─────┬─────► Hour      │
│                 6h    9h    12h   18h   21h               │
│                                                              │
│   BREAKING NEWS (unpredictable)                             │
│   ───────────────────────────                               │
│                                                              │
│   Visitors ▲                                               │
│            │           ▲ Sudden spike x10                  │
│   200,000 ─┤          ╱╲                                   │
│            │         ╱  ╲                                   │
│   100,000 ─┤        ╱    ╲                                 │
│            │       ╱      ╲                                 │
│    20,000 ─┤──────╱        ╲──────────                     │
│            │                                                 │
│            └─────────────────────────────────► Time        │
│                                                              │
└─────────────────────────────────────────────────────────────┘

Requirements

Aspect	Requirement
Availability	99.9%
Response time	< 500ms (P95)
Min capacity	5,000 visitors/min
Max capacity	200,000 visitors/min
Budget	Optimize costs outside peaks

Part 2: Design Exercises

Exercise 2.1: Sizing

Knowing that a t3.medium instance can handle 500 requests/second, calculate:

Question	Your Answer
Minimum instances (normal)	?
Instances for x10 spike	?
Recommended min for HA	?
Recommended max	?

💡 Solution

Normal traffic: 50,000 visitors/min = 833 req/sec
Instances needed: 833 / 500 = 2 instances

x10 spike traffic: 200,000 visitors/min = 3,333 req/sec
Instances needed: 3,333 / 500 = 7 instances (rounded)

Recommended min: 2 (HA Multi-AZ)
Recommended max: 10 (safety margin)

Desired initial: 2

Exercise 2.2: Policy Choice

Which scaling policy(ies) do you recommend and why?

Policy	Appropriate?	Justification
Target Tracking CPU	?	?
Target Tracking Requests	?	?
Scheduled	?	?
Step Scaling	?	?

💡 Solution

Policy	Appropriate?	Justification
Target Tracking CPU	⚠️ Partial	Useful but CPU not always correlated to requests
Target Tracking Requests	✅ YES	Directly related to user traffic
Scheduled	⚠️ Partial	Predictable day/night patterns, but not breaking news
Step Scaling	✅ YES	Quick response to sudden spikes

Recommendation: Combine Target Tracking (requests) + Scheduled (base)

Exercise 2.3: Launch Template Configuration

Complete the Launch Template configuration:

# Launch Template Configuration
LaunchTemplateName: newsportal-lt
  
# To complete:
AMI: _______________
InstanceType: _______________
SecurityGroupIds: 
  - _______________
KeyName: _______________
UserData: |
  #!/bin/bash
  _______________
  _______________
  _______________

💡 Solution

LaunchTemplateName: newsportal-lt
  
AMI: ami-0123456789 (Amazon Linux 2, preconfigured)
InstanceType: t3.medium
SecurityGroupIds: 
  - sg-web-servers
KeyName: newsportal-key
UserData: |
  #!/bin/bash
  yum update -y
  yum install -y httpd
  systemctl start httpd
  systemctl enable httpd
  # Or app deployment via CodeDeploy
  aws s3 cp s3://newsportal-deploy/latest.tar.gz /tmp/
  tar -xzf /tmp/latest.tar.gz -C /var/www/html/

Exercise 2.4: ASG Configuration

Complete the Auto Scaling Group configuration:

AutoScalingGroupName: newsportal-asg

# Capacity
MinSize: ___
MaxSize: ___
DesiredCapacity: ___

# Network (2 AZ minimum)
VPCZoneIdentifier:
  - _______________
  - _______________

# Health Checks
HealthCheckType: _______________
HealthCheckGracePeriod: ___

# Target Group
TargetGroupARNs:
  - _______________

💡 Solution

AutoScalingGroupName: newsportal-asg

MinSize: 2
MaxSize: 10
DesiredCapacity: 2

VPCZoneIdentifier:
  - subnet-private-az-a
  - subnet-private-az-b

HealthCheckType: ELB  # Uses ALB health checks
HealthCheckGracePeriod: 300  # 5 minutes for app startup

TargetGroupARNs:
  - arn:aws:elasticloadbalancing:...:targetgroup/newsportal-tg/xxx

Part 3: Policy Configuration

Exercise 3.1: Target Tracking

Create a Target Tracking policy to maintain 1000 requests per target:

# Complete the command
aws autoscaling put-scaling-policy \
    --auto-scaling-group-name newsportal-asg \
    --policy-name _______________ \
    --policy-type _______________ \
    --target-tracking-configuration '{
        "TargetValue": ___,
        "PredefinedMetricSpecification": {
            "PredefinedMetricType": "_______________",
            "ResourceLabel": "app/newsportal-alb/xxx/targetgroup/newsportal-tg/yyy"
        },
        "ScaleOutCooldown": ___,
        "ScaleInCooldown": ___
    }'

💡 Solution

aws autoscaling put-scaling-policy \
    --auto-scaling-group-name newsportal-asg \
    --policy-name request-target-tracking \
    --policy-type TargetTrackingScaling \
    --target-tracking-configuration '{
        "TargetValue": 1000.0,
        "PredefinedMetricSpecification": {
            "PredefinedMetricType": "ALBRequestCountPerTarget",
            "ResourceLabel": "app/newsportal-alb/xxx/targetgroup/newsportal-tg/yyy"
        },
        "ScaleOutCooldown": 60,
        "ScaleInCooldown": 300
    }'

Exercise 3.2: Scheduled Scaling

Configure scheduled scaling for day/night patterns:

# Morning scale up (8h UTC, Mon-Fri)
aws autoscaling put-scheduled-update-group-action \
    --auto-scaling-group-name newsportal-asg \
    --scheduled-action-name _______________ \
    --recurrence "_______________ " \
    --min-size ___ \
    --max-size ___

# Evening scale down (22h UTC, every day)
aws autoscaling put-scheduled-update-group-action \
    --auto-scaling-group-name newsportal-asg \
    --scheduled-action-name _______________ \
    --recurrence "_______________" \
    --min-size ___ \
    --max-size ___

💡 Solution

# Morning scale up (8h UTC, Mon-Fri)
aws autoscaling put-scheduled-update-group-action \
    --auto-scaling-group-name newsportal-asg \
    --scheduled-action-name morning-scale-up \
    --recurrence "0 8 * * MON-FRI" \
    --min-size 3 \
    --max-size 10

# Evening scale down (22h UTC, every day)
aws autoscaling put-scheduled-update-group-action \
    --auto-scaling-group-name newsportal-asg \
    --scheduled-action-name evening-scale-down \
    --recurrence "0 22 * * *" \
    --min-size 2 \
    --max-size 5

Part 4: Monitoring and Alerts

Exercise 4.1: CloudWatch Dashboard

List the essential metrics to monitor:

Metric	Namespace	Alert Threshold
?	AWS/EC2	?
?	AWS/ApplicationELB	?
?	AWS/AutoScaling	?
?	Custom	?

💡 Solution

Metric	Namespace	Alert Threshold
CPUUtilization	AWS/EC2	> 80%
TargetResponseTime	AWS/ApplicationELB	> 500ms
RequestCount	AWS/ApplicationELB	info only
HealthyHostCount	AWS/ApplicationELB	< 2
GroupDesiredCapacity	AWS/AutoScaling	info only
GroupInServiceInstances	AWS/AutoScaling	< min
HTTPCode_Target_5XX_Count	AWS/ApplicationELB	> 10/min

Exercise 4.2: Scaling Alert

Create an SNS alert to notify during scaling events:

# 1. Create the SNS topic
aws sns create-topic --name _______________

# 2. Subscribe via email
aws sns subscribe \
    --topic-arn arn:aws:sns:...:_______________ \
    --protocol email \
    --notification-endpoint _______________

# 3. Configure ASG notifications
aws autoscaling put-notification-configuration \
    --auto-scaling-group-name newsportal-asg \
    --topic-arn arn:aws:sns:...:_______________ \
    --notification-types \
        "autoscaling:EC2_INSTANCE_LAUNCH" \
        "autoscaling:EC2_INSTANCE_TERMINATE" \
        "_______________"

💡 Solution

# 1. Create the SNS topic
aws sns create-topic --name newsportal-scaling-alerts

# 2. Subscribe via email
aws sns subscribe \
    --topic-arn arn:aws:sns:us-east-1:123456789:newsportal-scaling-alerts \
    --protocol email \
    --notification-endpoint ops@newsportal.com

# 3. Configure ASG notifications
aws autoscaling put-notification-configuration \
    --auto-scaling-group-name newsportal-asg \
    --topic-arn arn:aws:sns:us-east-1:123456789:newsportal-scaling-alerts \
    --notification-types \
        "autoscaling:EC2_INSTANCE_LAUNCH" \
        "autoscaling:EC2_INSTANCE_TERMINATE" \
        "autoscaling:EC2_INSTANCE_LAUNCH_ERROR"

Part 5: Validation Tests

Test Plan

Test	Method	Expected Result
Scale Out	Generate load	New instances in < 5 min
Scale In	Stop load	Reduction after cooldown
Failover	Terminate instance	Auto replacement
Health Check	Stop app	Instance marked unhealthy

Load Test Script

#!/bin/bash
# test-load.sh - Simulate a traffic spike

ALB_DNS="newsportal-alb-xxx.region.elb.amazonaws.com"
DURATION=300  # 5 minutes
CONCURRENCY=100

echo "Starting load test..."
echo "URL: http://$ALB_DNS"
echo "Duration: $DURATION seconds"
echo "Concurrency: $CONCURRENCY"

# Use Apache Bench or hey
hey -z ${DURATION}s -c $CONCURRENCY http://$ALB_DNS/

echo "Test completed. Check CloudWatch and ASG."

Validation Checklist

┌─────────────────────────────────────────────────────────────┐
│              VALIDATION CHECKLIST                            │
├─────────────────────────────────────────────────────────────┤
│                                                              │
│   ☐ Scale out works (new instances)                         │
│   ☐ Scale in works (terminated instances)                   │
│   ☐ ALB health checks detect failures                       │
│   ☐ Unhealthy instances automatically replaced              │
│   ☐ SNS notifications received                              │
│   ☐ Metrics visible in CloudWatch                           │
│   ☐ Scheduled actions respected                             │
│   ☐ Response time maintained < 500ms under load             │
│                                                              │
└─────────────────────────────────────────────────────────────┘

Final Deliverable

Document to Produce

Auto Scaling Architecture (diagram)
Complete Configuration (Launch Template + ASG)
Scaling Policies (Target Tracking + Scheduled)
Monitoring Plan (metrics + alerts)
Test Results (CloudWatch screenshots)

Evaluation Criteria

Criterion	Points
Correct sizing	/15
Complete ASG configuration	/25
Policies suited to scenario	/20
Monitoring and alerts	/15
Documented tests	/15
Document quality	/10
Total	/100

Next week: MODULE 10 - Route 53

Lab Objective​

Part 1: Scenario​

Context​

Traffic Data​

Requirements​

Part 2: Design Exercises​

Exercise 2.1: Sizing​

Exercise 2.2: Policy Choice​

Exercise 2.3: Launch Template Configuration​

Exercise 2.4: ASG Configuration​

Part 3: Policy Configuration​

Exercise 3.1: Target Tracking​

Exercise 3.2: Scheduled Scaling​

Part 4: Monitoring and Alerts​

Exercise 4.1: CloudWatch Dashboard​

Exercise 4.2: Scaling Alert​

Part 5: Validation Tests​

Test Plan​

Load Test Script​

Validation Checklist​

Final Deliverable​

Document to Produce​

Evaluation Criteria​

Lab Objective

Part 1: Scenario

Context

Traffic Data

Requirements

Part 2: Design Exercises

Exercise 2.1: Sizing

Exercise 2.2: Policy Choice

Exercise 2.3: Launch Template Configuration

Exercise 2.4: ASG Configuration

Part 3: Policy Configuration

Exercise 3.1: Target Tracking

Exercise 3.2: Scheduled Scaling

Part 4: Monitoring and Alerts

Exercise 4.1: CloudWatch Dashboard

Exercise 4.2: Scaling Alert

Part 5: Validation Tests

Test Plan

Load Test Script

Validation Checklist

Final Deliverable

Document to Produce

Evaluation Criteria