Re: Guix vs GuixSD - upgrade Debian to Guix

[myglc2]

address@hidden writes:

> Hello,
>
> I have read this:
>
>> I am saying you can "upgrade" your computer from, say, Guix on Debian to
>> GuixSD by doing ...
>> 
>>      mount /dev/sdX /mnt
>>      guix system init /mnt/etc/config.scm /mnt
>> 
>> ... where /dev/sdX is a new system disk. With more complicated maneuvers
>> you can no doubt convert an existing system disk.
>
> So, would it be possible to upgrade Debian to Guix without
> completely new install from USB/CD?
>
> Louis

Hi Louis.

Yes. I confirmed that this works today.

Background: 6 weeks ago I installed GuixSD on one of my headless servers
using the USB key. A few weeks ago I installed Guix on another one that
is running Debian 8. Today I performed a successful "Guix/Debian -->
GuixSD Upgrade".

Experience: I found the Guix Binary install much easier than the USB key
GuixSD install.  I also found today's "GuixSD Upgrade" much easier than
the USB install, primarily because I was working in a fully functional
machine rather than a crippled install image. I don't know if the binary
install plus upgrade is quicker than an USB install. But if you already
have Guix installed on your machine, this will definately be easier than
the USB install.

Safety: Use a spare disk. This way you can always keep running
Guix/Debian if anything goes wrong.. But, you must be sure not to get
your physical disks mixed up because, if you do, you can BLOW YOUR
GUIX/DEBIAN SYSTEM AWAY. As always, you should have a backup before you
start something like this.

Disclaimer: This approach is not in the doc. I don't know how receptive
the Guix team is to this approach or to questions or bug reports that it
may generate.

My notes on what worked for me today are attached below.

Good luck! - George


** Guix/Debian --> GuixSD Upgrade

#+BEGIN_EXAMPLE

## starting with Guix installed and working on Debian 8

## note: operations below are performed as root

## note: this example installs GuixSD on a spare disk

## take stock of disks
lsblk

## pick a disk to receive guixSD. 
## In this example we use /dev/sdc

## unmount /dev/sdc if necessary

## wipe possible raid reminants
wipefs -af /dev/sdc

## wipe the MBR, if any
dd if=/dev/zero of=/dev/sdc bs=512 count=1

## create 1 256GB partition on the disk
sfdisk -u S /dev/sdc << EOF
2048,500116144,L
EOF

## double check our work
parted /dev/sdc print
## or
sfdisk -l -u S /dev/sdc

## make a root file system
mkfs.ext4 -L my-root /dev/sdc1

## mount the root file system
mkdir /mnt/guix-root
mount  -L my-root /mnt/guix-root

## edit bare-bones.scm 
## - change occurences of "sdX" to "sdc"
## - change the ssh port from "2222" to "22"
## - hostname
## - timezone
## - locale
## - make alice a sudo

## update guix version
guix pull

## install guixSD onto /dev/sdc
guix system init bare-bones.scm /mnt/guix-root

## copy bare-bones.scm to the new drive
cp bare-bones.scm /mnt/guix-root/etc/

## shutdown
shutdown now

## pull out the old disks or change to the new boot disk in the bios

## restart

## at the console 
## - random typing on the keyboard to make the system happy
## log in to root
passwd root
passwd alice

## ssh from another system
ssh address@hidden

## enjoy
#+END_EXAMPLE