Is it possible to attach one EBS volume to multiple EC2 instances simultaneously in AWS?

A standard EBS volume in AWS cannot be attached simultaneously to multiple EC2 instances in read-write mode. EBS volumes are designed to be attached to a single instance at a time.

However, there are exceptions and alternatives:

• Multi-Attach: For io1 and io2 volume types, Multi-Attach can be enabled, allowing a single volume to be attached to multiple instances simultaneously, but only in read-write mode with applications that support such access (e.g., database clusters).

• EFS (Elastic File System): If a file system with concurrent access from multiple instances is needed, it's better to use EFS — a network file service that supports multiple connections.

Thus, a standard EBS volume does not support simultaneous attachment to multiple EC2 instances, but there are special modes and alternatives for such scenarios.