Ravindra BagaleCourses & study guides

Chapter 14: EC2 Operations — Elastic IP, AMI, Snapshots and Vertical Scaling

Common Mistakes I See Students Make

By Last updated:

  • Allocating Elastic IPs and never releasing them — idle EIPs are still charged.
  • Forgetting to update SSH/DNS after associating an EIP — the old public IP is gone.
  • Deregistering an AMI but leaving its snapshots, which keep costing money.
  • Creating an AMI with "No reboot" from a busy database server and getting a corrupted copy.
  • Creating a volume from a snapshot in a different AZ from the instance — it cannot be attached.
  • Running mkfs on a volume restored from a snapshot, wiping the very data they wanted to recover.
  • Mounting an XFS copy on the same instance without nouuid and getting a "duplicate UUID" error.
  • Changing an x86 instance to a Graviton type and expecting it to boot.
  • Forgetting that the public IP changes after a type change and thinking the server is dead.
  • Scaling up beyond free-tier types and leaving it running.