Reinstall base Ubuntu without formatting or removing manually installed packages

Question

Because I played around too much with the proposed repository (on 14.04), I want to go back to step 1: remove every package on the system except those I've manually installed and reinstall the base system, without going through the hassle of reinstalling.

Basically, is there anyway to safely and remotely over ssh:

remove all packages except manually installed ones
reinstall everything from the kernel to ubuntu-desktop (preferably automagically without any further packages getting marked as manually installed)
install dependencies of the manually installed packages

N.B. I've intentionally left out 14.04 in hopes of getting answers unspecific to any particular version(s).

It seems I haven't described what I want simply enough, I think these two points would take care of the above:

purge all auto-installed packages (@kos answered that on @Fabby's answer)
install the packages that makes up a fresh Ubuntu install

And I'm guessing if the dependencies of manually installed packages do get uninstalled, apt-get -f will help me with them.

@j0h 1. Nothing important in /home, but there are important configuration in manually installed packages, 2. Yes, but as I said user files are not the worry, 3. Yes, it's enabled, 4. And yes, there's virtualization support as well. — Oxwivi, Oct 30 '15 at 02:35
This is a bit over my level of expertise, but wouldn't it be easier to get a packages list from a fresh install, diff it against your current install to get a list of everything added. Then do a fresh install and automagically add back in all the custom stuff - possibly with a restore of some or all of the config files in $HOME? You get the lists by running dpkg -l. This will probably mark a lot of the additional stuff as manually installed - rather than as dependencies which could go away if the package that needed them is deleted later. — Joe, Oct 30 '15 at 08:02

score 5 · Answer 1 · edited Apr 13 '17 at 12:23

5

For the future:

If you have a remote server in a Data centre 1000 miles away you'd better have an IPKVM switch installed so you don't have to rely solely on ssh to reach it.

If the server is on Mount Everest: add an Iridium phone and a modem as well...

Then you can have a bootable 512MB FAT CloneZilla partition on that machine (I use an SLC USB stick) and use the console to boot to that and back-up an image of your system partition(s) to your data drive and then copy the previous system image on the secondary partition of your USB stick before you start adding trusty-proposed to the server. (I keep most of my system back-ups on the data drive: they're only 6GB)

For now:

Take an apt-backup
Go through your /var/log/apt/history*
Make your own automagical script that does an apt-get purge of all the stuff you really don't want/need any more from the data in the previous step
Execute the script while praying to Linus of the Torvalds
Update your repositories like you want them to be (like removing trusty-proposed)
Reboot while praying to Richard of the Stallmans
If everything works out: implement the IPKVM switch solution above.

edited Apr 13 '17 at 12:23

Community

1

answered Oct 25 '15 at 14:45

Fabby

34,259

No automagical command of delete everything except this that? :( Do IPKVM switch come with dynamic DNS function? Worthless otherwise in this case. – Oxwivi Oct 25 '15 at 16:53
The above is the most automagical you'll get. Fully automatic like a Windows restore point: nope, that's what system back-ups are for... IPKVM switches can use DHCP, so by using an external Dynamic DNS service: "yes, kinda"... – Fabby Oct 25 '15 at 19:02
Nah, I hate Windows restore point thingy. No idea what goes in there. (More like, I've come to hate the whole frickin' Windows product line) The only automagical part I want is figuring out all manual packages and the command to uninstall everything except those. – Oxwivi Oct 25 '15 at 19:21
I deleted Windows about 2 years ago... Have you even tried looking in history.log??? :P – Fabby Oct 25 '15 at 19:43
@Oxwivi You want apt-mark showauto, and to purge all the package in the output by feeding the list to apt-cache purge: apt-mark showauto | xargs sudo apt-get --dry-run purge. I voluntarily added the --dry-run switch in case you're tempetd to try it, so that you can actually see what's happening: doing something like that breaks your installation, because it removes every package dependent on any of the package removed by the command. Just take a look at the output of the dry run. – kos Oct 28 '15 at 22:15
@Oxwivi My sincere suggestion is: either uninstall the packages selectively like suggested in this answer, or do a fresh reintall. – kos Oct 28 '15 at 22:15
@kos You should post your own answer. If I follow your lines, how can I reinstall all the auto packages that's installed on a fresh install? Will ubuntu-desktop install all the necessary kernel packages and stuff? I kinda doubt that. – Oxwivi Oct 30 '15 at 02:29
And both of you should calm down. I'm not about to execute this on the target machine without testing it out first... – Oxwivi Oct 30 '15 at 02:30
@Oxwivi that's why kos gave you the --dry-run switch: we're staying extremely calm and trying to help you succeed in your endeavours. – Fabby Oct 30 '15 at 08:12

score 1 · Answer 2 · answered Oct 29 '15 at 05:04

OK, My answer assumes you can, and have backed up your user directory, and everything you want to save. which reduces your question to how do I install Ubuntu on a remote server? To which there are many solutions.

For this, you could use DRBL, to remotely deploy an operating system, with a variety of options for booting. You can look into it here: http://drbl.org/installation/

There is Clobber: http://cobbler.github.io/manuals/quickstart/

There is cloneZilla, which can back up and restore over a network. The link is for windows, but the same methods apply for linux. Alternatively, you could make an ubuntu boot image locally, and install it using clonezilla. http://opensourceforu.efytimes.com/2013/12/restore-partitions-network-using-clonezilla/

Alternatively, you could try using dd_rescue, or netcat

A useful search term might be "Server Provisioning". There are more options then these.

There are bruteforce methods too.

$ ls /
bin  boot  cdrom  dev  etc  home  initrd.img  initrd.img.old  lib  lib64  lost+found  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var  vmlinuz  vmlinuz.old

and your PATH were like this:

echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games

if your root directory were something like this, if you over wrote /etc, and /usr with "clean" versions, you would be overwriting, pretty much every piece of installed software, and the config files for it. That would be hackerish to say the least, if not a completely horrible idea. Running apt-get purge would be much safer, Or perhaps you could fine tune the process a little bit. You might then also want to include a clone of your old ssh config file in /etc/ssh/ before trying to restart the services with new config files.

There is also a tool that lets you dump a running kernel and upgrade without rebooting. For that you could check out Kslpice, or kGraft

If all you are having trouble with is repos and package management, I'm not sure why you would want to dump the kernel, mbr, boot partition etc..

So any how, I hope Ive given you some ideas to look into. There are many ways to depoly a server remotely.

Reinstall base Ubuntu without formatting or removing manually installed packages

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