Amazon AWS EC2 Dashboard and SSH - Saving Text Files to Volumes

Question

As a new user of SSH and the Amazon AWS EC2 Dashboard, I am trying to test to see whether I can, in one instance, save data onto a volume, then access that data from another instance by adding the volume to the instance (after terminating the first instance).

When I create the first instance, the AMI is "Amazon Linux AMI 2014.03.2 (HVM)" and the family is "general purpose" with EBS storage only. I automatically assign a public IP address to the instance. I configure the root volume so that it does NOT delete on termination.

As soon as the instance is launched, I open up PuTTY and set the host name to the instance's Public IP Address under Port 22, and authenticate using a private key saved onto the disc that I have already generated earlier.

Upon signing into the instance, I create a text file by typing the following code: echo "testing">test.txt

I then confirm that the text "testing" is saved to the file "test.txt": less test.txt

I see the text "testing", thus confirming that it is saved to the file. (I am assuming at this point that it is saved onto the volume, but I am not entirely sure.)

I then proceed to terminate the instance. I launch another one using the same AMI, same instance type, and a different public IP address. In addition to the root volume, I attempt to add the volume that was used as the root volume for the previous instance. (Oddly enough, the snapchat IDs for the previous volume and the root volume of the new instance are identical.) In addition, I use the same tag instance, the same security group and the same key pair as the previous instance.

I open up PuTTY again, this time using the Public IP Address of the new instance, but still using the same private key and port used for the previous instance. Opening logging in, I type: less test.txt but I am greeted with this message: test.txt: No such file or directory

Is there any advice that anyone can offer me regarding this issue. Is it even possible to store a text file onto a volume? If so, am I performing this operation incorrectly?

Answer 1

As the secondary volume has the same UUID and the Amazon Linux used UUID based identification for root, then there might be a chance that the secondary volume was taken as the root volume. This may be the reason why there would be a mess up in choosing the root volume and the initial attempt to find test.txt would fail.

The reboot might have allowed it to take a different order which is why you were able to find it.