How to fix gzip: stdout: No space left on device in APT

First, determine how much space is available and what is consuming it:

df -h

Look for the /boot line. If it shows 100% or close to it (e.g., "/dev/sda1 228M 218M 0 100% /boot"), you need to free space immediately.

df -h | grep boot

Also check inode usage:

df -i /boot

If the IUse% is 100%, you have an inode problem rather than disk space.

See which kernel versions are currently installed:

dpkg -l 'linux-image-*' | grep '^ii'

This lists all installed kernel images. You'll see output like:

ii  linux-image-5.15.0-76-generic   5.15.0-76.83~20.04.1   amd64
ii  linux-image-5.15.0-78-generic   5.15.0-78.85~20.04.1   amd64
ii  linux-image-5.15.0-84-generic   5.15.0-84.93~20.04.1   amd64

Typically, you only need the currently running kernel and perhaps the previous one. All others are safe to remove.

Find your currently running kernel:

uname -r

Remove all but the currently running kernel. Replace X.X.X-XX with an old kernel version:

sudo apt-get remove linux-image-5.15.0-76-generic

Or remove multiple old kernels at once:

sudo apt-get remove linux-image-5.15.0-76-generic linux-image-5.15.0-78-generic

After removing each kernel, you should see space freed. Verify with:

df -h | grep boot

Remove kernels until /boot is below 80% capacity.

Once you've freed enough space, clean up dangling dependencies and old kernel-related packages:

sudo apt-get autoremove

This removes:
- Unused kernel headers
- Unused linux-modules packages
- Other orphaned dependencies

Then clean the package cache:

sudo apt-get clean

Verify /boot space again:

df -h | grep boot

If apt-get upgrade was interrupted, complete the installation:

sudo apt-get -f install

Or finish a stalled dpkg configuration:

sudo dpkg --configure -a

Then retry the upgrade:

sudo apt-get upgrade

Prevent this issue in the future by automatically removing old kernels when new ones arrive.

Option 1: Using apt-get autoremove automatically

Enable Debian's automatic cleanup by editing /etc/apt/apt.conf.d/50unattended-upgrades:

sudo nano /etc/apt/apt.conf.d/50unattended-upgrades

Ensure this line is uncommented:

Unattended-Upgrade::Remove-Unused-Kernel-Packages "true";
Unattended-Upgrade::Remove-Unused-Dependencies "true";

Option 2: Using ubuntu-kernel-purge (Ubuntu only)

sudo apt install ubuntu-kernel-purge

This tool automatically purges old kernel versions while keeping the current and at least one backup kernel.

Option 3: Manual cron job

Create a daily cleanup job:

sudo crontab -e

Add this line:

0 2 * * * apt-get autoremove -y >> /var/log/kernel-cleanup.log 2>&1

This runs autoremove daily at 2 AM.

If you frequently run out of space despite removing kernels, your /boot partition is too small. This is a more advanced fix.

Check current /boot size:

lsblk
# or
fdisk -l | grep boot

Resize the partition (requires downtime and can be risky):

Option A: Merge /boot with root filesystem (recommended for new systems)
- This requires reinstalling or using complex partition tools
- Not recommended unless you're rebuilding the system

Option B: Expand the existing /boot partition
- Requires live USB/boot media
- Use tools like GParted or fdisk
- Extends the partition and filesystem

For new installations: Use a larger /boot partition (500 MB to 1 GB). Most modern installers default to only 100-200 MB.

# View recommended size (modern kernels)
ls -lah /boot/

Sum of all kernel versions typically = 50 MB × (number of kernels). For 3-5 kernels, allocate 500 MB minimum.