接続と EC2 の基本管理

Your instance is running — now you need to get inside it. This lesson covers connecting securely and managing the basics: starting, stopping, and monitoring.

Your SSH key pair unlocks the instance: the private .pem stays on your machine, the public key lives on the server. SSH uses both to log you in without a password.

On Linux or macOS, connect with the ssh command and your key. First lock down the key's permissions, then point it at your instance's public DNS or IP.

On Windows, WSL lets you use the same ssh command as Linux. PuTTY (convert the key to .ppk first) and Git Bash also work well.

An instance moves through lifecycle states: pending, running, stopping, stopped, shutting-down, and terminated. Stopped still costs storage; terminated is gone for good.

Stopping saves the instance's state to disk so you can restart it — handy for pausing costs or changing instance type. Note: a fresh public IP is assigned on restart unless you use an Elastic IP.

Terminating permanently deletes an instance and its instance-store data; attached EBS volumes persist by default. It's irreversible — always double-check first.

CloudWatch collects metrics from your AWS resources, including EC2. Check the Monitoring tab on an instance for real-time health and performance.

Watch the key EC2 metrics: CPU utilization (high means under-resourced), network in/out for traffic bottlenecks, and disk read/write operations.

Your EC2 instance is currently in the Stopped state. Which of the following is TRUE about its current status and billing?

Recap: connect over SSH with a key pair, know the lifecycle states and their cost and data implications, and watch CloudWatch metrics like CPU and network.