My /boot partition hit 100% and now I can't upgrade. Can't remove old kernels to make room

Freeing Up Space on the Root File System

To free up space on the root file system you can try to execute apt-get clean.

If that doesn't work you can go to /var/cache/apt/archives and manually remove a few files from the cache to get some space back, e.g.:

sudo rm linux-headers-*

It won't hurt to remove all of the .deb files here if you need to - that is what apt-get clean does. They will be automatically be re-downloaded by apt if they are needed again.

Freeing Up Space on the /boot File System

The Original Poster has a separate /boot partition, and that is what is full and preventing the apt system from working. It will be necessary for him to free up space there.

If there almost enough space, go to /boot and remove a config file or two:

sudo rm config-3.2.0-19-generic-pae

for example, but using the name of one of the kernel versions you intend to remove anyway. This will free up a little space (about 144K apiece).

If you need more space individually remove old vmlinuz, initrd, abi and System.map files until you have enough space (about 22M for one of my i386 kernel versions).

Whatever you do, don't remove them all. You should at least keep the latest two matching versions of each kind of file, for each kind of kernel you use.

Then proceed with your apt-get install commands. As mentioned above they may have to re-download some of the debs you deleted, but if so that will happen automatically. When you have apt working again, clean up by using apt-get to remove the packages corresponding to the files you removed - so everything matches.

The config file in /boot is the kernel config that was used by the kernel team to build the kernel of the same name. It should be harmless to remove unless you want it for reference or to aid you in building your own kernels.

Finally you are manually removing an old kernel package or two from the /boot partition to make even more room for the new one.

In my case, the apt commands and dpkg command could not finish, and could not remove. The autoupdate had failed on installing 2.6.32-56-server.

My first step, was to identify space to be used,

cd /boot
du -sk *|sort -n

I had about 30 kernels and supporting files.

I did a uname -a to get the running kernel, I identified that I was on Linux alternate 2.6.32-43-server and did a tar of 6 of the versions that were not running, and were old.

tar -cvf ~username/boot.tar *2.6.32-44-server *2.6.32-45-server *2.6.32-46-server *2.6.32-47-server *2.6.32-48-server *2.6.32-49-server

I then did a rm -rf of what I had backed up:

rm -rf *2.6.32-44-server *2.6.32-45-server *2.6.32-46-server *2.6.32-47-server *2.6.32-48-server *2.6.32-49-server

I am showing these commands as examples, you will have to decide what you will work with for your situation.

Now that I had some space on /boot, I was able to run

apt-get -f install 

To clean up the failed install of 2.6.32-56-server.

I then did a

apt-get remove linux-headers-2.6.32-38 linux-headers-2.6.32-38-server linux-image-2.6.32-38-server
apt-get remove linux-headers-2.6.32-39 linux-headers-2.6.32-39-server linux-image-2.6.32-39-server

This gave me room to put back what I had backed up.

tar -xf ~username/boot.tar
rm  ~username/boot.tar    

To clean up, I then could run:

apt-get autoremove

I rebooted and am now down to using 4% of /boot.

You can use dpkg instead of apt-get to remove older kernels:

sudo dpkg -r linux-image-3.2.0-29-generic

I noticed there were still some files of the old versions in the boot directory:

$ ls /boot
vmcoreinfo-2.6.31-17-server

And the package manager would list the old versions:

dpkg -l | grep linux-image

I therefore used this command (autoremove would also remove more recent images I don't want to remove)

sudo apt-get purge linux-image-2.6.31-17-server

I had still some headers left:

dpkg -l | grep linux-headers

So I did this:

sudo apt-get purge linux-headers-2.6.32-34

Finally there was one package left I couldn't remove with apt-get purge:

$ dpkg -l | grep linux-image
rc  linux-image-2.6.28-11-server

Source: Remove a package marked as rc by dpkg

sudo dpkg --purge linux-image-2.6.28-11-server

I found that the only thing that worked for me was using Aptitude.

sudo aptitude

Then when it opens it will usually say something about unmet dependencies on the bottom. You can hit the letter g to proceed with the suggested removal. It will take you to a page where it lists what is going to happen.

There should be a minus - next to the broken kernels. Press g again and it will remove the broken kernels. Press q to quit. Then you should be able to use sudo apt-get autoremove to get rid of the old kernels and free up space.

UPDATE 2022: Another way is to manually remove some kernel files, especially if aptitude isn't installed:

First check your running kernel to make sure you don't delete it:

uname -r

Then list the modules directory:

ls /usr/lib/modules/

For example, here is a list from one of my servers:

drwxr-xr-x 5 root root 4096 Mar  2 14:16 5.4.0-100-generic
drwxr-xr-x 2 root root  250 Apr 27  2021 5.4.0-26-generic
drwxr-xr-x 2 root root  250 May 13  2021 5.4.0-28-generic
drwxr-xr-x 2 root root  250 Oct 26 14:01 5.4.0-72-generic
drwxr-xr-x 2 root root  250 Oct 26 14:01 5.4.0-73-generic
drwxr-xr-x 2 root root  250 Oct 26 14:01 5.4.0-80-generic
drwxr-xr-x 2 root root  250 Mar 11 16:20 5.4.0-84-generic
drwxr-xr-x 2 root root  250 Mar 11 16:20 5.4.0-89-generic
drwxr-xr-x 2 root root  250 Mar 11 16:20 5.4.0-91-generic
drwxr-xr-x 5 root root 4096 Feb  1 14:15 5.4.0-97-generic

Remove all but the newest 2 from this directory. For example:

sudo rm -rf 5.4.0-26-generic 5.4.0-28-generic 5.4.0-72-generic 5.4.0-73-generic 5.4.0-80-generic 5.4.0-84-generic 5.4.0-89-generic 5.4.0-91-generic

Also check the /boot directory and do the same process there.

Then check to see if some space was freed up:

df -h

Finally run apt to fix the broken packages:

sudo apt -f install

Check the use of /var/tmp with du -sh /var/tmp/. All files in that folder can be deleted to make space.

You can then run the following to remove the old kernels:

sudo apt-get clean
sudo apt install byobu
sudo purge-old-kernels
sudo apt autoremove
sudo update-grub

Install linux-purge tool like this.

Then run this in terminal:

sudo linux-purge --clear-boot --fix

Then go on removing kernels by e.g.

sudo linux-purge --keep 1 --choose

Extra:

If I recall correctly there is a default setting in Ubuntu 18.04 and later for unattended-upgrades that removes unneeded kernels, but it can not cope with the case that system is already full: The setting is Unattended-Upgrade::Remove-Unused-Kernel-Packages true.

If you want to use linux-purge for unattended kernel removal instead of using unattended-upgrades for that, you should disable removing unused kernels by editing /etc/apt/apt.conf.d/50unattended-upgrades or preferably an overriding separate file (e.g. /etc/apt/apt.conf.d/52unattended-upgrades-local); that means at least setting

Unattended-Upgrade::Remove-Unused-Dependencies false;
Unattended-Upgrade::Remove-Unused-Kernel-Packages false;

Thereafter set up a systemd service executing

/usr/local/bin/linux-purge --auto-only --keep 1 --yes

whenever you want.

You cannot act upon packages, but you can act upon other files. First, go through your home folder and see whether there is anything you can delete. If not, try to move a good amount of files to another partition (or a flash drive) and then try sudo apt-get install -f to clean up the package dependency issues (most likely you installed a .deb file through dpkg), and then purge any old kernels. Once you safely have at least 10 MB, try purging unneeded software or files.

This is what I used:

sudo apt-get autoremove linux-image-xxxx

Do that for all old kernels and only keep the most recent two.

If you want to automatically remove the old kernels and update GRUB see this: Ubuntu Documentation

Run this:

sudo apt-get autoremove
sudo apt-get --purge remove && sudo apt-get autoclean
sudo apt-get -f install
sudo dpkg-reconfigure -a

Source: I get this error after upgade. please help