Ubuntu Server 18.04 LVM out of space with improper default partitioning

Problem Statement:

I installed Ubuntu Server 18.04 with the LVM option and left the default partition setup. Now my main drive only has 4GB in a 1TB hard drive. How can I fix this without starting from scratch?

Results of df -h :

Filesystem Size Used Available Use% Mounted on
udev 16G 0 16G 0% /dev
tmpfs 32G 1.7M 32G 1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv 3.9G 3.6G 92M 98% / 
tmpfs 16G 0 16G 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/loop0 87M 87M 0 100% /snap/core/4917
/dev/loop1 3.2M 3.2M 0 100% /snap/stress-ng/471
/dev/loop2 90M 90M 0 100% /snap/core/6130
/dev/sda2 976M 143M 766M 16% /boot
tmpfs 3.2G 0 3.2G 0% /run/user/1000

Resolution:

Had the exact same problem with a fresh install of Ubuntu Server 18.04.1. What I had to do was:

# We need to resize the logical volume to use all the existing and free space of the volume group

$ lvm
lvm> lvextend -l +100%FREE /dev/ubuntu-vg/ubuntu-lv
lvm> exit

# And then, we need to resize the file system to use the new available space in the logical volume

$ resize2fs /dev/ubuntu-vg/ubuntu-lv

resize2fs 1.44.1 (24-Mar-2018)
Filesystem at /dev/ubuntu-vg/ubuntu-lv is mounted on /; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 58
The filesystem on /dev/ubuntu-vg/ubuntu-lv is now 120784896 (4k) blocks long.

# Finally, you can check that you now have available space:

$ df -h

Filesystem Size Used Avail Use% Mounted on
udev 3.9G 0 3.9G 0% /dev
tmpfs 786M 1.2M 785M 1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv 454G 3.8G 432G 1% /

If you didn’t customize the LVM settings, the names for the volume group and logical volume should be the same as mine (ubuntu-vg and ubuntu-lv respectively).

If your partition is completely full, you could get a no space left error when trying to resize the logical volume like:

lvm> lvextend -l +100%FREE /dev/ubuntu-vg/ubuntu-lv
/etc/lvm/archive/.lvm_computer: write error failed: No space left on device

The easiest way to fix this is by removing apt cache (it will get regenerated next time you do apt update), which should give you more than enough space to complete the operation:

$ rm -rf /var/cache/apt/*