Best way to Restore EC2 Instance

There are indeed two main approaches to restoring an EC2 instance, and you've correctly identified them. Let's explore the differences and considerations for each method:

1. Restoring from an AMI (Amazon Machine Image):

   • This method creates a new EC2 instance based on the AMI.
   • It's a more comprehensive approach, as it captures the entire instance configuration, including all attached volumes, instance type, and other settings.
   • Ideal for full instance recovery or when you need to replicate the entire environment.
   • The restored instance will have a new private IP address by default, but you can retain the original private IP if needed (more on this later).
   • This method is generally faster for full instance recovery.

2. Restoring from EBS snapshots:

   • This approach allows you to restore individual volumes.
   • It's more flexible, as you can choose to restore only specific volumes or even individual files and directories.
   • Useful when you need to recover specific data rather than the entire instance.
   • You can create new volumes from the snapshots and attach them to an existing instance.
   • This method can be more time-consuming if you need to restore multiple volumes and reconfigure the instance.

Additional considerations:

• If you need to retain the same private IP address when restoring from an AMI, you can do so by configuring the Elastic Network Interface (ENI) attached to the original EC2 instance not to be deleted when the instance is terminated. Then, when launching the new instance from the AMI, you can select that ENI to inherit the same IP address.

• When restoring from snapshots, you have the flexibility to restore to different instance types or even create larger volumes if needed.

• For both methods, it's crucial to regularly test your restore process in non-production environments to ensure it meets your recovery point objective (RPO) and recovery time objective (RTO).

• If you're using Elastic Load Balancing with multiple instances, you can take a failed or impaired instance out of service and restore a new one to replace it without disrupting user traffic.

• When choosing an instance type for the restored instance, select one that matches or exceeds the specifications of the original virtual machine to ensure optimal performance.

In summary, using an AMI is generally the best approach for full instance recovery, while snapshot-based restoration offers more flexibility for recovering specific data or volumes. The choice between the two methods depends on your specific recovery needs and the level of granularity required in the restore process.

Sources
Restore an Amazon EC2 instance - AWS Backup
Restoring an Amazon EBS volume or an EC2 instance - AWS Prescriptive Guidance
how to Restore EC2 ( windows OS ) From AMI image and retain private IP Address | AWS re:Post
Restore a virtual machine using AWS Backup - AWS Backup

Hello,
Basically, restoring using AMI will restore the whole instance with its associated volumes.
Restoring using snapshots will restore the EBS volumes and not the instance itself.

For full instance recovery, better to use AMI.
For rolling back specific volume or restoring data, better to use snapshots.
Amazon EC2 backup and recovery with snapshots and AMIs

You can consider using AWS Backup to backup your EC2 instance.

When restoring, AWS Backup will select for you the instance type, VPC, subnet, security group, and instance IAM role that is associated with your original EC2 instance. When you restore from AMI or snapshot, you have to manually select these values yourself.