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Amazon EC2 Essentials

Essential AWS Elastic Compute Cloud concepts for virtual server management

March 10, 2024
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Updated regularly

Amazon EC2 Essentials

Quick reference guide for AWS Elastic Compute Cloud (EC2).

What is Amazon EC2?

Amazon EC2 provides scalable virtual servers in the cloud:

  • Virtual machines (instances) in the AWS cloud
  • Complete control over operating system and software
  • Flexible sizing (CPU, memory, storage, networking)
  • Pay-as-you-go or reserved pricing
  • Global infrastructure with multiple regions and availability zones
  • Auto Scaling for dynamic workloads

    • Instance Types

    General Purpose

    T-Series (Burstable)
├── t4g: ARM-based, best value (up to 40% cost savings)
├── t3: Intel/AMD, balanced performance
└── t2: Previous generation

M-Series (Balanced)
├── m7g: ARM-based, latest generation
├── m6i: Intel, general purpose
└── m5: Previous generation Intel

    Use Cases: Web servers, development environments, small databases

    Compute Optimized

    C-Series
├── c7g: ARM-based, highest performance
├── c6i: Intel, compute intensive
└── c5: Previous generation

    Use Cases: Batch processing, high-performance web servers, gaming servers

    Memory Optimized

    R-Series (Memory Intensive)
├── r7g: ARM-based, large memory
├── r6i: Intel, memory optimized
└── r5: Previous generation

X-Series (Extreme Memory)
└── x2: Up to 4TB RAM

    Use Cases: In-memory databases (Redis, SAP HANA), big data analytics

    Storage Optimized

    I-Series (High IOPS)
└── i4i: NVMe SSD storage

D-Series (Dense Storage)
└── d3: HDD-based, large capacity

    Use Cases: NoSQL databases, data warehousing, log processing

    Accelerated Computing

    P-Series (GPU - ML/AI)
├── p4: NVIDIA A100 GPUs
└── p3: NVIDIA V100 GPUs

G-Series (GPU - Graphics)
└── g5: NVIDIA A10G GPUs

    Use Cases: Machine learning, video processing, gaming

    Launching Instances

    AWS CLI - Launch Instance

    # ========== Launch Basic Instance ==========
aws ec2 run-instances \
  --image-id ami-12345678 \
  --instance-type t3.micro \
  --key-name my-key-pair \
  --security-group-ids sg-12345678 \
  --subnet-id subnet-12345678 \
  --count 1 \
  --tag-specifications 'ResourceType=instance,Tags=[{Key=Name,Value=MyInstance}]'

# ========== Launch with User Data ==========
aws ec2 run-instances \
  --image-id ami-12345678 \
  --instance-type t3.micro \
  --key-name my-key-pair \
  --security-group-ids sg-12345678 \
  --subnet-id subnet-12345678 \
  --user-data file://user-data.sh

# ========== Launch with Multiple Storage Volumes ==========
aws ec2 run-instances \
  --image-id ami-12345678 \
  --instance-type t3.medium \
  --key-name my-key-pair \
  --block-device-mappings '[
    {
      "DeviceName": "/dev/xvda",
      "Ebs": {
        "VolumeSize": 30,
        "VolumeType": "gp3",
        "DeleteOnTermination": true,
        "Encrypted": true
      }
    },
    {
      "DeviceName": "/dev/sdf",
      "Ebs": {
        "VolumeSize": 100,
        "VolumeType": "gp3",
        "DeleteOnTermination": false
      }
    }
  ]'

    User Data Script

    #!/bin/bash
# This script runs on instance first launch

# Update packages
yum update -y

# Install web server
yum install -y httpd

# Start web server
systemctl start httpd
systemctl enable httpd

# Create simple webpage
echo "<h1>Hello from EC2!</h1>" > /var/www/html/index.html

# Install CloudWatch agent
wget https://s3.amazonaws.com/amazoncloudwatch-agent/amazon_linux/amd64/latest/amazon-cloudwatch-agent.rpm
rpm -U ./amazon-cloudwatch-agent.rpm

    Instance Management

    Start, Stop, Reboot

    # ========== Start Instance ==========
aws ec2 start-instances --instance-ids i-1234567890abcdef0

# ========== Stop Instance ==========
aws ec2 stop-instances --instance-ids i-1234567890abcdef0

# ========== Reboot Instance ==========
aws ec2 reboot-instances --instance-ids i-1234567890abcdef0

# ========== Terminate Instance ==========
aws ec2 terminate-instances --instance-ids i-1234567890abcdef0

    Describe and List Instances

    # ========== List All Instances ==========
aws ec2 describe-instances

# ========== List Running Instances ==========
aws ec2 describe-instances \
  --filters "Name=instance-state-name,Values=running" \
  --query "Reservations[].Instances[].[InstanceId,InstanceType,PublicIpAddress,Tags[?Key=='Name'].Value|[0]]" \
  --output table

# ========== Get Instance Details ==========
aws ec2 describe-instances \
  --instance-ids i-1234567890abcdef0

# ========== List Instances by Tag ==========
aws ec2 describe-instances \
  --filters "Name=tag:Environment,Values=production"

    Modify Instance

    # ========== Change Instance Type ==========
# 1. Stop the instance
aws ec2 stop-instances --instance-ids i-1234567890abcdef0

# 2. Wait for stopped state
aws ec2 wait instance-stopped --instance-ids i-1234567890abcdef0

# 3. Modify instance type
aws ec2 modify-instance-attribute \
  --instance-id i-1234567890abcdef0 \
  --instance-type "{\"Value\": \"t3.medium\"}"

# 4. Start the instance
aws ec2 start-instances --instance-ids i-1234567890abcdef0

# ========== Enable Termination Protection ==========
aws ec2 modify-instance-attribute \
  --instance-id i-1234567890abcdef0 \
  --disable-api-termination

# ========== Disable Termination Protection ==========
aws ec2 modify-instance-attribute \
  --instance-id i-1234567890abcdef0 \
  --no-disable-api-termination

    Elastic Block Store (EBS)

    Volume Types

    TypeUse CaseIOPSThroughputSize
    gp3General purpose SSD3,000-16,000125-1,000 MB/s1GB-16TB
    gp2General purpose SSD (legacy)100-16,000Up to 250 MB/s1GB-16TB
    io2High performance SSDUp to 64,000Up to 1,000 MB/s4GB-16TB
    st1Throughput optimized HDD500Up to 500 MB/s125GB-16TB
    sc1Cold HDD (lowest cost)250Up to 250 MB/s125GB-16TB

    EBS Commands

    # ========== Create Volume ==========
aws ec2 create-volume \
  --volume-type gp3 \
  --size 100 \
  --availability-zone us-east-1a \
  --encrypted \
  --tag-specifications 'ResourceType=volume,Tags=[{Key=Name,Value=MyVolume}]'

# ========== Attach Volume ==========
aws ec2 attach-volume \
  --volume-id vol-1234567890abcdef0 \
  --instance-id i-1234567890abcdef0 \
  --device /dev/sdf

# ========== Detach Volume ==========
aws ec2 detach-volume \
  --volume-id vol-1234567890abcdef0

# ========== Create Snapshot ==========
aws ec2 create-snapshot \
  --volume-id vol-1234567890abcdef0 \
  --description "Backup before upgrade" \
  --tag-specifications 'ResourceType=snapshot,Tags=[{Key=Name,Value=MySnapshot}]'

# ========== List Snapshots ==========
aws ec2 describe-snapshots --owner-ids self

# ========== Delete Snapshot ==========
aws ec2 delete-snapshot --snapshot-id snap-1234567890abcdef0

# ========== Modify Volume ==========
aws ec2 modify-volume \
  --volume-id vol-1234567890abcdef0 \
  --size 200 \
  --volume-type gp3 \
  --iops 4000

    Mount EBS Volume (Linux)

    # ========== Check Available Disks ==========
lsblk

# ========== Create Filesystem ==========
sudo mkfs -t ext4 /dev/xvdf

# ========== Mount Volume ==========
sudo mkdir /data
sudo mount /dev/xvdf /data

# ========== Persist Mount (Add to /etc/fstab) ==========
# Get UUID
sudo blkid /dev/xvdf

# Add to /etc/fstab
echo "UUID=your-uuid-here /data ext4 defaults,nofail 0 2" | sudo tee -a /etc/fstab

# ========== Verify ==========
df -h

    AMI (Amazon Machine Image)

    Create AMI

    # ========== Create AMI from Instance ==========
aws ec2 create-image \
  --instance-id i-1234567890abcdef0 \
  --name "MyApp-v1.0-$(date +%Y%m%d)" \
  --description "MyApp production image" \
  --no-reboot

# ========== Create AMI with Reboot ==========
aws ec2 create-image \
  --instance-id i-1234567890abcdef0 \
  --name "MyApp-v1.0" \
  --reboot

# ========== List AMIs ==========
aws ec2 describe-images --owners self

# ========== Deregister AMI ==========
aws ec2 deregister-image --image-id ami-1234567890abcdef0

# ========== Copy AMI to Another Region ==========
aws ec2 copy-image \
  --source-region us-east-1 \
  --source-image-id ami-1234567890abcdef0 \
  --region us-west-2 \
  --name "MyApp-v1.0-west"

    Security Groups

    Security Group Commands

    # ========== Create Security Group ==========
aws ec2 create-security-group \
  --group-name web-sg \
  --description "Security group for web servers" \
  --vpc-id vpc-1234567890abcdef0

# ========== Add Inbound Rules ==========
# Allow HTTP
aws ec2 authorize-security-group-ingress \
  --group-id sg-1234567890abcdef0 \
  --protocol tcp \
  --port 80 \
  --cidr 0.0.0.0/0

# Allow HTTPS
aws ec2 authorize-security-group-ingress \
  --group-id sg-1234567890abcdef0 \
  --protocol tcp \
  --port 443 \
  --cidr 0.0.0.0/0

# Allow SSH from specific IP
aws ec2 authorize-security-group-ingress \
  --group-id sg-1234567890abcdef0 \
  --protocol tcp \
  --port 22 \
  --cidr 203.0.113.0/24

# Allow traffic from another security group
aws ec2 authorize-security-group-ingress \
  --group-id sg-1234567890abcdef0 \
  --protocol tcp \
  --port 3306 \
  --source-group sg-0987654321fedcba0

# ========== Remove Inbound Rule ==========
aws ec2 revoke-security-group-ingress \
  --group-id sg-1234567890abcdef0 \
  --protocol tcp \
  --port 22 \
  --cidr 0.0.0.0/0

# ========== List Security Groups ==========
aws ec2 describe-security-groups

# ========== Delete Security Group ==========
aws ec2 delete-security-group --group-id sg-1234567890abcdef0

    Key Pairs

    Key Pair Management

    # ========== Create Key Pair ==========
aws ec2 create-key-pair \
  --key-name my-key-pair \
  --query 'KeyMaterial' \
  --output text > my-key-pair.pem

# Set proper permissions
chmod 400 my-key-pair.pem

# ========== List Key Pairs ==========
aws ec2 describe-key-pairs

# ========== Delete Key Pair ==========
aws ec2 delete-key-pair --key-name my-key-pair

# ========== Import Existing Key ==========
aws ec2 import-key-pair \
  --key-name imported-key \
  --public-key-material fileb://~/.ssh/id_rsa.pub

    Connect to Instance

    # ========== SSH Connection ==========
ssh -i my-key-pair.pem ec2-user@54.123.45.67

# For Ubuntu
ssh -i my-key-pair.pem ubuntu@54.123.45.67

# ========== SSH with Port Forwarding ==========
ssh -i my-key-pair.pem -L 8080:localhost:80 ec2-user@54.123.45.67

# ========== SCP File Transfer ==========
# Upload file
scp -i my-key-pair.pem file.txt ec2-user@54.123.45.67:/home/ec2-user/

# Download file
scp -i my-key-pair.pem ec2-user@54.123.45.67:/home/ec2-user/file.txt ./

# ========== Session Manager (No SSH Key Needed) ==========
aws ssm start-session --target i-1234567890abcdef0

    Elastic IP (Static IP)

    Elastic IP Commands

    # ========== Allocate Elastic IP ==========
aws ec2 allocate-address --domain vpc

# ========== Associate Elastic IP ==========
aws ec2 associate-address \
  --instance-id i-1234567890abcdef0 \
  --allocation-id eipalloc-12345678

# ========== Disassociate Elastic IP ==========
aws ec2 disassociate-address --association-id eipassoc-12345678

# ========== Release Elastic IP ==========
aws ec2 release-address --allocation-id eipalloc-12345678

# ========== List Elastic IPs ==========
aws ec2 describe-addresses

    Auto Scaling

    Launch Template

    # ========== Create Launch Template ==========
aws ec2 create-launch-template \
  --launch-template-name my-template \
  --version-description "v1" \
  --launch-template-data '{
    "ImageId": "ami-12345678",
    "InstanceType": "t3.micro",
    "KeyName": "my-key-pair",
    "SecurityGroupIds": ["sg-12345678"],
    "UserData": "IyEvYmluL2Jhc2gKeXVtIHVwZGF0ZSAteQ==",
    "TagSpecifications": [{
      "ResourceType": "instance",
      "Tags": [{
        "Key": "Name",
        "Value": "AutoScaled-Instance"
      }]
    }]
  }'

# ========== Create Auto Scaling Group ==========
aws autoscaling create-auto-scaling-group \
  --auto-scaling-group-name my-asg \
  --launch-template "LaunchTemplateName=my-template,Version=1" \
  --min-size 2 \
  --max-size 10 \
  --desired-capacity 2 \
  --vpc-zone-identifier "subnet-12345,subnet-67890" \
  --health-check-type ELB \
  --health-check-grace-period 300 \
  --tags "Key=Environment,Value=production,PropagateAtLaunch=true"

# ========== Update Auto Scaling Group ==========
aws autoscaling update-auto-scaling-group \
  --auto-scaling-group-name my-asg \
  --desired-capacity 5

# ========== Create Scaling Policy ==========
aws autoscaling put-scaling-policy \
  --auto-scaling-group-name my-asg \
  --policy-name scale-up \
  --policy-type TargetTrackingScaling \
  --target-tracking-configuration '{
    "PredefinedMetricSpecification": {
      "PredefinedMetricType": "ASGAverageCPUUtilization"
    },
    "TargetValue": 70.0
  }'

    Load Balancer Integration

    Application Load Balancer

    # ========== Create Target Group ==========
aws elbv2 create-target-group \
  --name my-targets \
  --protocol HTTP \
  --port 80 \
  --vpc-id vpc-12345678 \
  --health-check-path /health \
  --health-check-interval-seconds 30

# ========== Register Instances ==========
aws elbv2 register-targets \
  --target-group-arn arn:aws:elasticloadbalancing:region:account:targetgroup/my-targets \
  --targets Id=i-1234567890abcdef0 Id=i-0987654321fedcba0

# ========== Create Load Balancer ==========
aws elbv2 create-load-balancer \
  --name my-alb \
  --subnets subnet-12345 subnet-67890 \
  --security-groups sg-12345678

# ========== Create Listener ==========
aws elbv2 create-listener \
  --load-balancer-arn arn:aws:elasticloadbalancing:region:account:loadbalancer/app/my-alb \
  --protocol HTTP \
  --port 80 \
  --default-actions Type=forward,TargetGroupArn=arn:aws:elasticloadbalancing:region:account:targetgroup/my-targets

    Monitoring and Logging

    CloudWatch Metrics

    # ========== Get CPU Utilization ==========
aws cloudwatch get-metric-statistics \
  --namespace AWS/EC2 \
  --metric-name CPUUtilization \
  --dimensions Name=InstanceId,Value=i-1234567890abcdef0 \
  --start-time 2024-01-01T00:00:00Z \
  --end-time 2024-01-02T00:00:00Z \
  --period 3600 \
  --statistics Average

# ========== Create Alarm ==========
aws cloudwatch put-metric-alarm \
  --alarm-name high-cpu \
  --alarm-description "Alert when CPU exceeds 80%" \
  --metric-name CPUUtilization \
  --namespace AWS/EC2 \
  --statistic Average \
  --period 300 \
  --threshold 80 \
  --comparison-operator GreaterThanThreshold \
  --evaluation-periods 2 \
  --dimensions Name=InstanceId,Value=i-1234567890abcdef0 \
  --alarm-actions arn:aws:sns:region:account:my-topic

    Instance Metadata

    # ========== Get Instance ID ==========
curl http://169.254.169.254/latest/meta-data/instance-id

# ========== Get Instance Type ==========
curl http://169.254.169.254/latest/meta-data/instance-type

# ========== Get Public IP ==========
curl http://169.254.169.254/latest/meta-data/public-ipv4

# ========== Get User Data ==========
curl http://169.254.169.254/latest/user-data

# ========== IMDSv2 (More Secure) ==========
TOKEN=$(curl -X PUT "http://169.254.169.254/latest/api/token" -H "X-aws-ec2-metadata-token-ttl-seconds: 21600")
curl -H "X-aws-ec2-metadata-token: $TOKEN" http://169.254.169.254/latest/meta-data/instance-id

    Pricing Models

    On-Demand Instances

    Pay per hour/second with no commitment
├── Best for: Short-term, unpredictable workloads
├── Flexibility: Highest
└── Cost: Highest per hour

    Reserved Instances

    1 or 3 year commitment for significant discount (up to 72%)
├── Standard RI: Fixed instance type and region
├── Convertible RI: Can change instance type
└── Scheduled RI: Run on specific schedule

    Savings Plans

    Flexible pricing model (1 or 3 year commitment)
├── Compute Savings Plans: Up to 66% savings
├── EC2 Instance Savings Plans: Up to 72% savings
└── Flexibility: Can change instance type, OS, region

    Spot Instances

    Up to 90% discount, can be interrupted
├── Best for: Fault-tolerant workloads
├── Use cases: Batch processing, data analysis
└── Risk: Can be terminated with 2-minute warning

    Best Practices

    Security

  • Use IAM roles instead of storing credentials on instances
  • Enable encryption for EBS volumes
  • Use Security Groups as firewalls (least privilege)
  • Disable SSH password authentication (key-based only)
  • Use Systems Manager Session Manager instead of SSH
  • Enable VPC Flow Logs for network monitoring
  • Keep instances updated with security patches
  • Use private subnets for backend instances

    • Performance

  • Choose appropriate instance type for workload
  • Use Enhanced Networking (SR-IOV)
  • Enable EBS optimization for disk-intensive workloads
  • Use gp3 volumes for better price/performance
  • Place instances in multiple AZs for high availability
  • Use placement groups for low-latency applications

    • Cost Optimization

  • Right-size instances based on actual usage
  • Stop unused instances instead of leaving them running
  • Use Spot Instances for non-critical workloads
  • Purchase Reserved Instances or Savings Plans
  • Delete unattached EBS volumes
  • Delete old snapshots
  • Use Auto Scaling to match demand
  • Monitor with Cost Explorer and set budgets

    • Reliability

  • Use multiple Availability Zones
  • Create regular AMI backups
  • Automate with CloudFormation/Terraform
  • Enable termination protection for critical instances
  • Use Auto Scaling Groups for self-healing
  • Implement health checks
  • Use Load Balancers for traffic distribution

    • Troubleshooting

    Common Issues

    # ========== Cannot Connect via SSH ==========
# Check security group allows port 22
# Verify key pair permissions (chmod 400)
# Check instance is running
# Verify public IP/DNS

# ========== Instance Status Checks Failing ==========
# System status check: AWS infrastructure issue
# Instance status check: OS/application issue
aws ec2 describe-instance-status --instance-ids i-1234567890abcdef0

# ========== Disk Space Full ==========
df -h
# Clean up logs, delete unused files
# Increase EBS volume size

# ========== High CPU Usage ==========
top
# Identify processes consuming CPU
# Optimize application or upgrade instance type

# ========== View System Logs ==========
aws ec2 get-console-output --instance-id i-1234567890abcdef0

    Tips

  • Tag everything for organization and cost tracking
  • Use Systems Manager for centralized management
  • Enable detailed monitoring for critical instances
  • Automate with CloudFormation or Terraform
  • Use AWS Backup for automated backups
  • Implement proper naming conventions
  • Document your architecture
  • Regular security audits with AWS Config
  • Use AWS Cost Anomaly Detection
  • Leverage AWS Compute Optimizer for recommendations

    • Resources

  • AWS EC2 Documentation
  • EC2 Instance Types
  • EC2 Pricing Calculator
  • AWS Well-Architected Framework
  • EC2 Best Practices

    • Topics

    AWSEC2CloudInfrastructureDevOps
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