AWS EC2

Deploy and manage Amazon EC2 compute instances for production, staging, and development workloads.

When to Use This Skill

• Launching new compute instances for application hosting
• Building golden AMIs for consistent deployments
• Setting up auto-scaling groups behind load balancers
• Migrating workloads to Spot instances for cost savings
• Troubleshooting instance connectivity, performance, or launch failures
• Creating launch templates for repeatable infrastructure

Prerequisites

• AWS CLI v2 installed and configured (aws configure)
• IAM permissions: ec2:*, autoscaling:*, elasticloadbalancing:*, iam:PassRole
• An existing VPC with subnets (see aws-vpc)
• SSH key pair created (aws ec2 create-key-pair --key-name my-key --query 'KeyMaterial' --output text > my-key.pem)

Instance Type Selection Guide

Category	Types	Use Case
General Purpose	t3, t3a, m6i, m7g	Web servers, small databases, dev/test
Compute Optimized	c6i, c7g	Batch processing, media encoding, ML inference
Memory Optimized	r6i, r7g, x2idn	In-memory caches, large databases
Storage Optimized	i3, i4i, d3	Data warehousing, distributed file systems
Accelerated	p4d, g5, inf2	ML training, GPU rendering, inference
Burstable	t3.micro-t3.2xlarge	Low-steady-state with occasional bursts

Launch an Instance

# Launch a production web server
aws ec2 run-instances \
  --image-id ami-0abcdef1234567890 \
  --instance-type t3.medium \
  --key-name my-key \
  --security-group-ids sg-12345678 \
  --subnet-id subnet-12345678 \
  --iam-instance-profile Name=EC2AppProfile \
  --metadata-options "HttpTokens=required,HttpEndpoint=enabled" \
  --block-device-mappings '[{
    "DeviceName": "/dev/xvda",
    "Ebs": {
      "VolumeSize": 30,
      "VolumeType": "gp3",
      "Iops": 3000,
      "Throughput": 125,
      "Encrypted": true
    }
  }]' \
  --tag-specifications 'ResourceType=instance,Tags=[
    {Key=Name,Value=web-server-01},
    {Key=Environment,Value=production},
    {Key=Team,Value=platform}
  ]' \
  --user-data file://userdata.sh

# Launch with IMDSv2 required (security best practice)
aws ec2 run-instances \
  --image-id ami-0abcdef1234567890 \
  --instance-type t3.micro \
  --metadata-options "HttpTokens=required,HttpPutResponseHopLimit=1,HttpEndpoint=enabled" \
  --tag-specifications 'ResourceType=instance,Tags=[{Key=Name,Value=secure-instance}]'

User Data Scripts

#!/bin/bash
# userdata.sh - Bootstrap a web server on Amazon Linux 2023
set -euxo pipefail

# System updates
dnf update -y

# Install and start web server
dnf install -y nginx
systemctl enable nginx
systemctl start nginx

# Install CloudWatch agent
dnf install -y amazon-cloudwatch-agent
/opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl \
  -a fetch-config -m ec2 \
  -s -c ssm:AmazonCloudWatch-linux

# Install CodeDeploy agent
dnf install -y ruby wget
cd /home/ec2-user
wget https://aws-codedeploy-us-east-1.s3.us-east-1.amazonaws.com/latest/install
chmod +x ./install
./install auto

# Signal CloudFormation (if launched via CFN)
# /opt/aws/bin/cfn-signal -e $? --stack ${AWS::StackName} --resource ASG --region ${AWS::Region}

Launch Templates

# Create a launch template with full configuration
aws ec2 create-launch-template \
  --launch-template-name web-server-template \
  --version-description "v1 - AL2023 with nginx" \
  --launch-template-data '{
    "ImageId": "ami-0abcdef1234567890",
    "InstanceType": "t3.medium",
    "KeyName": "my-key",
    "SecurityGroupIds": ["sg-12345678"],
    "IamInstanceProfile": {"Name": "EC2AppProfile"},
    "MetadataOptions": {
      "HttpTokens": "required",
      "HttpEndpoint": "enabled"
    },
    "BlockDeviceMappings": [{
      "DeviceName": "/dev/xvda",
      "Ebs": {
        "VolumeSize": 30,
        "VolumeType": "gp3",
        "Encrypted": true
      }
    }],
    "TagSpecifications": [{
      "ResourceType": "instance",
      "Tags": [
        {"Key": "Environment", "Value": "production"},
        {"Key": "ManagedBy", "Value": "launch-template"}
      ]
    }],
    "Monitoring": {"Enabled": true},
    "UserData": "'"$(base64 -w0 userdata.sh)"'"
  }'

# Create a new version of the launch template
aws ec2 create-launch-template-version \
  --launch-template-name web-server-template \
  --source-version 1 \
  --version-description "v2 - updated AMI" \
  --launch-template-data '{"ImageId": "ami-0newami1234567890"}'

# Set the default version
aws ec2 modify-launch-template \
  --launch-template-name web-server-template \
  --default-version 2

Auto Scaling Group

# Create ASG with mixed instances (on-demand + spot)
aws autoscaling create-auto-scaling-group \
  --auto-scaling-group-name web-asg \
  --mixed-instances-policy '{
    "LaunchTemplate": {
      "LaunchTemplateSpecification": {
        "LaunchTemplateName": "web-server-template",
        "Version": "$Default"
      },
      "Overrides": [
        {"InstanceType": "t3.medium"},
        {"InstanceType": "t3a.medium"},
        {"InstanceType": "m5.large"}
      ]
    },
    "InstancesDistribution": {
      "OnDemandBaseCapacity": 2,
      "OnDemandPercentageAboveBaseCapacity": 25,
      "SpotAllocationStrategy": "capacity-optimized"
    }
  }' \
  --min-size 2 --max-size 10 --desired-capacity 4 \
  --vpc-zone-identifier "subnet-aaa,subnet-bbb" \
  --target-group-arns "arn:aws:elasticloadbalancing:us-east-1:123456789012:targetgroup/web-tg/abc123" \
  --health-check-type ELB \
  --health-check-grace-period 300 \
  --tags '[
    {"Key":"Name","Value":"web-asg","PropagateAtLaunch":true},
    {"Key":"Environment","Value":"production","PropagateAtLaunch":true}
  ]'

# Create target tracking scaling policy (target 60% CPU)
aws autoscaling put-scaling-policy \
  --auto-scaling-group-name web-asg \
  --policy-name cpu-target-tracking \
  --policy-type TargetTrackingScaling \
  --target-tracking-configuration '{
    "PredefinedMetricSpecification": {
      "PredefinedMetricType": "ASGAverageCPUUtilization"
    },
    "TargetValue": 60.0,
    "ScaleInCooldown": 300,
    "ScaleOutCooldown": 60
  }'

# Create scheduled scaling for known traffic patterns
aws autoscaling put-scheduled-update-group-action \
  --auto-scaling-group-name web-asg \
  --scheduled-action-name scale-up-morning \
  --recurrence "0 8 * * MON-FRI" \
  --min-size 4 --max-size 20 --desired-capacity 8

aws autoscaling put-scheduled-update-group-action \
  --auto-scaling-group-name web-asg \
  --scheduled-action-name scale-down-evening \
  --recurrence "0 20 * * MON-FRI" \
  --min-size 2 --max-size 10 --desired-capacity 2

Spot Instances

# Request Spot instances
aws ec2 request-spot-instances \
  --spot-price "0.05" \
  --instance-count 3 \
  --type "one-time" \
  --launch-specification '{
    "ImageId": "ami-0abcdef1234567890",
    "InstanceType": "c5.xlarge",
    "KeyName": "my-key",
    "SecurityGroupIds": ["sg-12345678"],
    "SubnetId": "subnet-12345678"
  }'

# Check current Spot prices
aws ec2 describe-spot-price-history \
  --instance-types t3.medium t3a.medium m5.large \
  --availability-zone us-east-1a \
  --product-descriptions "Linux/UNIX" \
  --start-time "$(date -u +%Y-%m-%dT%H:%M:%SZ)" \
  --query "SpotPriceHistory[].{Type:InstanceType,Price:SpotPrice,AZ:AvailabilityZone}" \
  --output table

# Create a Spot Fleet request
aws ec2 request-spot-fleet \
  --spot-fleet-request-config '{
    "IamFleetRole": "arn:aws:iam::123456789012:role/aws-ec2-spot-fleet-role",
    "TargetCapacity": 10,
    "SpotPrice": "0.10",
    "AllocationStrategy": "capacityOptimized",
    "LaunchSpecifications": [
      {"ImageId": "ami-xxx", "InstanceType": "c5.xlarge", "SubnetId": "subnet-aaa"},
      {"ImageId": "ami-xxx", "InstanceType": "c5a.xlarge", "SubnetId": "subnet-bbb"}
    ]
  }'

AMI Management

# Create an AMI from a running instance
aws ec2 create-image \
  --instance-id i-0abc123def456 \
  --name "web-server-$(date +%Y%m%d)" \
  --description "Web server golden AMI" \
  --no-reboot \
  --tag-specifications 'ResourceType=image,Tags=[
    {Key=Name,Value=web-server-golden},
    {Key=Version,Value=2026.03.24}
  ]'

# Copy AMI to another region for disaster recovery
aws ec2 copy-image \
  --source-image-id ami-0abcdef1234567890 \
  --source-region us-east-1 \
  --region us-west-2 \
  --name "web-server-dr-copy"

# Deregister old AMIs and delete associated snapshots
aws ec2 deregister-image --image-id ami-old123
aws ec2 delete-snapshot --snapshot-id snap-old123

# Share AMI with another AWS account
aws ec2 modify-image-attribute \
  --image-id ami-0abcdef1234567890 \
  --launch-permission "Add=[{UserId=987654321098}]"

Instance Management

# List running instances with key details
aws ec2 describe-instances \
  --filters "Name=instance-state-name,Values=running" \
  --query "Reservations[].Instances[].{ID:InstanceId,Type:InstanceType,IP:PrivateIpAddress,Name:Tags[?Key=='Name']|[0].Value,State:State.Name}" \
  --output table

# Stop and start instances
aws ec2 stop-instances --instance-ids i-0abc123def456
aws ec2 start-instances --instance-ids i-0abc123def456

# Resize an instance (stop first)
aws ec2 stop-instances --instance-ids i-0abc123def456
aws ec2 wait instance-stopped --instance-ids i-0abc123def456
aws ec2 modify-instance-attribute \
  --instance-id i-0abc123def456 \
  --instance-type '{"Value": "t3.large"}'
aws ec2 start-instances --instance-ids i-0abc123def456

# Get console output for debugging boot issues
aws ec2 get-console-output --instance-id i-0abc123def456

# Get instance screenshot (helps debug GUI issues)
aws ec2 get-console-screenshot --instance-id i-0abc123def456

Terraform EC2 with Auto Scaling

resource "aws_launch_template" "web" {
  name_prefix   = "web-"
  image_id      = data.aws_ami.amazon_linux.id
  instance_type = "t3.medium"

  iam_instance_profile {
    name = aws_iam_instance_profile.web.name
  }

  metadata_options {
    http_tokens   = "required"
    http_endpoint = "enabled"
  }

  block_device_mappings {
    device_name = "/dev/xvda"
    ebs {
      volume_size = 30
      volume_type = "gp3"
      encrypted   = true
    }
  }

  user_data = base64encode(file("userdata.sh"))

  tag_specifications {
    resource_type = "instance"
    tags = {
      Name        = "web-server"
      Environment = "production"
    }
  }
}

resource "aws_autoscaling_group" "web" {
  name                = "web-asg"
  min_size            = 2
  max_size            = 10
  desired_capacity    = 4
  vpc_zone_identifier = [aws_subnet.private_a.id, aws_subnet.private_b.id]
  target_group_arns   = [aws_lb_target_group.web.arn]
  health_check_type   = "ELB"

  launch_template {
    id      = aws_launch_template.web.id
    version = "$Latest"
  }

  tag {
    key                 = "Name"
    value               = "web-asg"
    propagate_at_launch = true
  }
}

resource "aws_autoscaling_policy" "cpu" {
  name                   = "cpu-target-tracking"
  autoscaling_group_name = aws_autoscaling_group.web.name
  policy_type            = "TargetTrackingScaling"

  target_tracking_configuration {
    predefined_metric_specification {
      predefined_metric_type = "ASGAverageCPUUtilization"
    }
    target_value = 60.0
  }
}

Troubleshooting

Problem	Cause	Fix
Instance stuck in pending	Insufficient capacity	Try a different AZ or instance type
Cannot SSH to instance	Security group or NACL blocks port 22	Check SG ingress rules and route tables
Instance immediately terminates	EBS volume limit or AMI issue	Check describe-instances for StateReason
IMDSv1 deprecation warnings	Metadata options not set	Set HttpTokens=required in launch template
User data not running	Script missing shebang or not base64	Verify #!/bin/bash header; check /var/log/cloud-init-output.log
Spot instance terminated	Capacity reclaimed by AWS	Use capacity-optimized allocation and diversify types
ASG not replacing unhealthy	Health check grace period too short	Increase grace period to cover app boot time
EBS throughput bottleneck	gp2 volume too small for IOPS	Migrate to gp3 and set explicit IOPS/throughput

Related Skills

• aws-vpc - VPC networking, subnets, and security groups
• aws-iam - Instance profiles and roles
• aws-cost-optimization - Rightsizing and Spot strategies
• terraform-aws - Infrastructure as Code deployment
• cloudformation - AWS-native IaC templates