Gremoire

Complete Guide: Setting up EC2 Instances Using AWS CLI ​

This guide explains how to launch, manage, and connect to EC2 instances using the AWS CLI.

Step 0 — Prerequisites ​

  1. AWS Account
  2. AWS CLI Installed & Configured
bash
aws configure
  • Enter your Access Key ID, Secret Access Key, region, and output format (json)
  1. Key Pair for SSH Access
  • You will need a key pair to connect via SSH.

Step 1 — Create a Key Pair ​

bash
aws ec2 create-key-pair --key-name MyKeyPair --query 'KeyMaterial' --output text > MyKeyPair.pem
  • Make the key private:
bash
chmod 400 MyKeyPair.pem

Step 2 — Choose an AMI (Amazon Machine Image) ​

  • List available AMIs:
bash
aws ec2 describe-images --owners amazon --filters "Name=name,Values=amzn2-ami-hvm-*-x86_64-gp2" --query 'Images[*].[ImageId,Name]' --output table
  • Note the ImageId you want (e.g., ami-0abcdef1234567890).

Step 3 — Create a Security Group ​

bash
aws ec2 create-security-group --group-name MySecurityGroup --description "My EC2 security group"
  • Add inbound rule to allow SSH:
bash
aws ec2 authorize-security-group-ingress --group-name MySecurityGroup --protocol tcp --port 22 --cidr 0.0.0.0/0
  • Add inbound rule for HTTP (optional):
bash
aws ec2 authorize-security-group-ingress --group-name MySecurityGroup --protocol tcp --port 80 --cidr 0.0.0.0/0

Step 4 — Launch an EC2 Instance ​

bash
aws ec2 run-instances \
    --image-id ami-0abcdef1234567890 \
    --count 1 \
    --instance-type t2.micro \
    --key-name MyKeyPair \
    --security-groups MySecurityGroup

  • Options:

    • --count → number of instances
    • --instance-type → instance size (t2.micro is free tier eligible)

  • After launching, note the InstanceId.

Step 5 — Describe Instances ​

bash
aws ec2 describe-instances --query 'Reservations[*].Instances[*].[InstanceId,State.Name,PublicIpAddress]' --output table
  • Check Public IP to connect via SSH.

Step 6 — Connect via SSH ​

bash
ssh -i "MyKeyPair.pem" ec2-user@<Public-IP>
  • For Amazon Linux, default username is ec2-user.
  • For Ubuntu, use ubuntu.

Step 7 — Stop, Start, and Terminate Instances ​

Stop an instance ​

bash
aws ec2 stop-instances --instance-ids i-0123456789abcdef0

Start an instance ​

bash
aws ec2 start-instances --instance-ids i-0123456789abcdef0

Terminate an instance ​

bash
aws ec2 terminate-instances --instance-ids i-0123456789abcdef0

Step 8 — Optional: Tagging Resources ​

bash
aws ec2 create-tags --resources i-0123456789abcdef0 --tags Key=Name,Value=MyEC2Instance
  • Helps identify instances in AWS console.

Step 9 — Summary Workflow ​

  1. aws ec2 create-key-pair → create key for SSH
  2. aws ec2 describe-images → choose AMI
  3. aws ec2 create-security-group → allow SSH/HTTP
  4. aws ec2 run-instances → launch instance
  5. aws ec2 describe-instances → get Public IP
  6. ssh -i → connect
  7. stop/start/terminate → manage instance lifecycle

✅ Tips ​

  • Use t2.micro for free tier testing.
  • Security groups are like firewall rules; restrict SSH to your IP for safety.
  • Always terminate instances when done to avoid charges.
  • Combine AWS CLI with scripts for automation.