FileSystem has duplicate UUID can’t mount in Linux (Amazon AWS)

Issue

FileSystem has duplicate UUID can’t mount when the root volume of an instance attached to another instance to fix an issue with an /etc/fstab file in Amazon AWS.

See the below screenshots for more information.

The /var/log/messages shows the below error.

Short Description

In Amazon AWS, a RHEL7 machine didn’t come up after a reboot. When I looked at the EC2 Get System Log and Get Instance Screenshot I found there is an issue with the /etc/fstab file

So, decided to use the AWS EC2 Root Volume Recovery Process where we used to follow to correct the KeyPair lose or OS config file update

After attaching our EBS root volume to a new instance and when I try to mount the disk with a temporary directory. I got a strange error as I mentioned above.

The above error shows it is happening because of the FileSystem duplicate UUID. When I did little further deep into it, I found the current instance and the old problem instance is using the same AMI and they had the same duplicate UUID for their root devices hence this issue arises.

Resolution

We have multiple ways to fix this issue.

  1. Use the -o nouuid option in mount command.
    mount -o nouuid /dev/xvdf2 /temp10
  1. Launch a brand new instance using AWS designated AMI or some trusted community AMI which you want to use for this recovery process

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