Amazon Elastic File System (EFS) is a fully managed, scalable file storage service designed to be used with Amazon EC2. It allows multiple instances to share data easily by providing a file system that can be mounted across different EC2 instances.

Steps to Create and Mount AWS EFS

1. Create an EFS File System:

   • Go to the AWS Management Console.
   • Navigate to EFS (Elastic File System).
   • Click Create file system.
   • Choose the appropriate VPC and subnets. Ensure that your EC2 instances are in the same VPC.
   • Configure security groups and permissions for access to the file system.
   • Click Create to complete the EFS creation.

2. Launch Two EC2 Instances:

   • Navigate to the EC2 Dashboard.
   • Launch two EC2 instances in the same VPC and subnets that were used for the EFS.
   • Make sure both instances have appropriate IAM roles and security groups to allow NFS (Network File System) traffic.

3. Mount the EFS on Both EC2 Instances:

   • SSH into your first EC2 instance.
   • Create a directory to mount the EFS:

     sudo mkdir /efs
     

   • Use the command taken from EFS -> Attach section in AWS.
   • Repeat the same steps for the second EC2 instance to mount the same EFS.

4. Verify Shared Access:

   • On the first EC2 instance, create a file inside the /efs directory:

     echo "Hello from instance 1" > /efs/shared-file.txt
     

   • On the second EC2 instance, check if the file exists inside /efs:

     cat /efs/shared-file.txt
     

   Both instances should have access to the same file, confirming that the data is shared between them.