Changing Partition UUIDs

[Mandar Joshi]

This is in continuation to the discussion on changing the partition
UUIDs on a fresh install of a Fedora 22 ARM install using the
changeuuid.py script in RootFS Build Factory.
Links:

You need to follow up from this message
https://lists.centos.org/pipermail/arm-dev/2015-December/001478.html

I know its a bit unusual to change mailing lists but I thought that if
we were discussing a Fedora Image, we should do so on a Fedora mailing
list.

Regards
Mandar Joshi

[1] https://github.com/mndar/rbf
[2] https://github.com/mndar/rbf/tree/master/commonscripts

[Robert Moskowitz]

On 12/28/2015 07:44 PM, Mandar Joshi wrote:
> This is in continuation to the discussion on changing the partition
> UUIDs on a fresh install of a Fedora 22 ARM install using the
> changeuuid.py script in RootFS Build Factory.
> Links:
>
> You need to follow up from this message
> https://lists.centos.org/pipermail/arm-dev/2015-December/001478.html
>
> I know its a bit unusual to change mailing lists but I thought that if
> we were discussing a Fedora Image, we should do so on a Fedora mailing
> list.

I will explain a bit about what we have stumbled on over on Centos-arm 
that impacts the Fedora-arm images.

Basically it came about me realizing the obvious that all systems would 
have the same UUIDs for the partitions and asking if that was a problem.

Karanbir contributed that this is a problem stating:

"this is a bad idea, it means you cant ( or will haveto do some work )
if you ever intend to share media. onprem, lesser issue ( likely only
when disaster recovery is involved ), but this is a much bigger issue
in offprem, where block device mobility is part of the larger picture
and taken for granted.

so, we should fix it."

So we have been looking in how to alter the UUID of the 3 partitions 
after the image is dd to the media.  I did some initial testing, and 
Mandar has contributed our first script for this.  I would see for 
Fedora-arm, this functionality being added to fedora-arm-installer script.

Any and all help you can provide for this should make it better for all.

thank you

[Mandar Joshi]

> My system (F22) started developing problems and I finally had to reboot.  I run the script a number of times and
> strangeness was occuring, ending with /dev/sdb not disapearing after removing one mSD card, and then could
> no longer dd to new cards that were trying to mount as /dev/sdb.  I don't know if the script was at fault or
> something, else.  But things definitely went south.

Just wanted to clarify, did you try to run the changeuuid.py script on
the same card as the one running the OS?
> One clear problem with this script is that the [INFO] messages report the old UUID wrong after the first time
> run.  Each time it lists the old UUIDs as the last UUIDs.  Not the UUIDs on the device.

The output of the changeuuid.py script would be really useful in debugging.