title: Upgrading from T2.medium to T3.medium
body: <p>My instance (Amazon AMI) has two network interfaces : eth0 and eth1. I would like to upgrade from T2.Medium to T3.Medium. </p>
  
  <p>But, it gives me an error saying :</p>
  
  <blockquote>
    <p>Enhanced networking with the Elastic Network Adapter (ENA) is
    required for the 't3.medium' instance type. Ensure that your instance
    is enabled for ENA.</p>
  </blockquote>
  
  <p>So, I found out that running the command  <em>"aws ec2 modify-instance-attribute --instance-id instance_id --ena-support"</em> will enable ENA support. </p>
  
  <p>Now, would it enable ENA support for both eth0 and eth1 ?</p>
  
  <p>I have found a script <em><a href="https://github.com/awslabs/aws-support-tools/tree/master/EC2/C5M5InstanceChecks" rel="noreferrer">https://github.com/awslabs/aws-support-tools/tree/master/EC2/C5M5InstanceChecks</a></em> that checks pre-requisites. </p>
  
  <p>It modified the "“/etc/fstab” to replace the device name of each partition with its UUID. Is it a safe operation ?</p>
  
  <p>Do I need to install NVMe module to upgrade from T2 to T3 ?</p>
  
  <p>If anything goes wrong (like I cant boot or status check failed etc), can I switch back to my backup and t2 reliably ?</p>
  
  <p>Thank You.</p>