AWS — EC2

What is EC2?

Elastic Compute Cloud provides resizable virtual servers in the cloud.

Instance types

Type	Use Case
t2.micro	Free tier, testing
t3.medium	General purpose
m5.large	Memory intensive
c5.xlarge	Compute optimized
r5.2xlarge	Memory optimized

Launch instance

aws ec2 run-instances \
  --image-id ami-0c55b159cbfafe1f0 \
  --instance-type t2.micro \
  --key-name my-key \
  --security-group-ids sg-12345678 \
  --subnet-id subnet-12345678

Instance states

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

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

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

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

Connect to instance

# SSH
ssh -i key.pem ec2-user@public-dns

# SSM (no SSH needed)
aws ssm start-session --target i-1234567890abcdef0

Security groups

# Create security group
aws ec2 create-security-group \
  --group-name my-sg \
  --description "My security group"

# Add inbound rule
aws ec2 authorize-security-group-ingress \
  --group-id sg-12345678 \
  --protocol tcp \
  --port 22 \
  --cidr 0.0.0.0/0

Elastic IP

# Allocate
aws ec2 allocate-address

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

Best practices

1. Use key pairs for SSH
2. Restrict security groups
3. Use IAM roles
4. Monitor with CloudWatch

Mini Practice

1. Launch an instance
2. Connect via SSH
3. Create a security group
4. Assign an Elastic IP

Up Next

Continue with S3 - Object Storage.