What is the difference between volume and blockdevicemapping tags in EC2 CloudFormation

Question

I understand that AWS::EC2::Volume resource type creates an EBS volume.

1. What exactly is the purpose of BlockDeviceMappings property in EC2 then?
2. How can I create multiple volumes in EC2 using AWS CloudFormation?

Answer 1

I hope this diagram helps:

Now to your questions,

1. I understand that AWS::EC2::Volume resource type creates an EBS volume. What exactly is the purpose of BlockDeviceMappings property in EC2 then?

This is better explained in this answer: "With BlockDeviceMappings you can mount ephemeral storage, not only EBS. Volumes is only EBS volumes, and provides better options (like choosing the AZ, or specifying the IOPs if you want to use PIOPs). If all what you want is simple EBS volumes, then there is no difference."

2. How can I create multiple volumes in EC2 using AWS CloudFormation?

Depends on the volume type you want. If you need instance storage, then use the BlockDeviceMappings property of AWS::EC2::Instance. If you need EBS volumes, use either BlockDeviceMapping or AWS::EC2::Volume.