Re: Squeeze dpkg --get-selections usable in any way in Wheezy?

On Tue, Dec 3, 2013 at 5:39 PM, Neal Murphy <neal.p.murphy@alum.wpi.edu> wrote:

On Tuesday, December 03, 2013 05:26:37 PM Lisi Reisz wrote:
> I have had another failed upgrade. Before I tried to upgrade, I ran
> dpkg --get-selections and saved the result in a file.
>
> I am obviously going to have to install Wheezy from scratch. Is there
> any way I can make use of Squeeze's package list to give the owner of
> the box the same applications/packages as she had in Squeeze, mutatis
> mutandis?

This topic was recently discussed, I think within the last 2-3 weeks. ... Ah,
11/4: "Re: Installing same packages in a Squeeze installation in a new Wheezy
installation". Excerpt from a thread summary I posted:

----
The theory is that --get-selections will list all installed pkgs in a form
that can be used by --set-selections to (re)install them.

So, on the existing system:
# Mount a thumb drive; change 'sdg' as needed
mount /dev/sdg1 /mnt

# Save the list of pkgs
dpkg --get-selections > /mnt/current_installed_pkgs.txt

# Umount, then unplug the drive
umount /mnt

And on the new system, first netinstall a basic system. Then
# Mount the thumb drive; change 'sdd' as needed
mount /dev/sdd1 /mnt

# Set the list of pkgs to install
dpkg --set-selections < /mnt/current_installed_pkgs.txt

# Unmount and remove the thumb drive
umount /mnt

# Start the 'upgrade'
apt-get dselect-upgrade
When done, the new system should have the same pkgs as the old system. It
won't be identical, but it'll be close.

Neal beat me to the punch, Lisi.

One point I would like to make is that it is probably not a bad idea to capture this from all of your machines as a starting point to have a pool of machine "types." For instance, being a believer in bastion hosts, I have a separate firewall, backup machine, fileserver, workstations, laptop, and containers (OpenVZ) for, for instance, mediawiki box, puppet master, etc. Each machine runs a script (installed by puppet) that runs at 4am that does an dpkg --get-selections and writes it to the filesytem. This is backed up daily. This way, if I am building a new box of a type, I have a base config from which to work.

--b