problem modifying starcluster AMI - ubuntu password change does not persist

From: Dan Tenenbaum <no email>
Date: Tue, 17 Jun 2014 12:17:03 -0700 (PDT)

Hello,

This might sound like an EC2 question that has nothing to do with starcluster, and in fact I have asked it on some AWS forums (there've been no answers). However, I have never encountered this problem before until I started modifying a starcluster AMI, so I wonder if it is related to what's on that AMI.

I made a custom AMI based on the starcluster AMI ami-3393a45a (us-east-1 starcluster-base-ubuntu-13.04-x86_64 (EBS))).

I installed a bunch of additional software and I also set the password of the ubuntu user to (let's say) 'foobar'.

The reason I did that is that I installed a web app that uses unix usernames and passwords for authentication. So I needed the ubuntu user to have a known password.

I then made a new image based on my running instance. Then I started a new instance from that image.
I ssh'd to that instance as the ubuntu user and typed 'passwd'. I was prompted for my existing password and entered 'foobar'. I then got:

passwd: Authentication token manipulation error
passwd: password unchanged

This tells me that the password for ubuntu is not 'foobar'.

Another way to test this is to try 'su - ubuntu'. This prompts for the password, I enter 'foobar' and it says "su: Authentication failure".

So...in a nutshell, when I change the ubuntu password, this change does not survive the process of creating a new AMI.

Could this be due to the way the starcluster AMI is configured? Is there some script that runs when it boots that re-sets that password? I'm not passing any user-data when I start the instance.....(I also tried a crontab _at_reboot job that changes the password and that didn't work either....so maybe whatever is messing me up is happening after that job is run).

Thanks,
Dan
Received on Tue Jun 17 2014 - 15:17:07 EDT