How to expand swap partition after system installation

expand_swap_partition_LVM_LUKS.txt

# How to expand swap partition after system installation
# Supposed that installing Ubuntu with LVM and Encrypted with LUKS default. So, current swap is 1G and /dev/sda4 is encrypted. You want to add +3G to become +4G. 

# Open encrypted partition, it is /dev/sda4 in this case
sudo cryptsetup luksOpen /dev/sda4 encrypted
sudo vgscan
sudo vgchange --activate y vgubuntu
sudo pvs
sudo vgs
sudo lvs

# Check and reduce /dev/mapper/vgubuntu-root
sudo e2fsck -f /dev/mapper/vgubuntu-root
sudo resize2fs /dev/mapper/vgubuntu-root  5G
# Remember 5G > 3G to safely reduce LVM Logical Volume.
sudo lvreduce -L -3G /dev/mapper/vgubuntu-root
sudo resize2fs /dev/mapper/vgubuntu-root

# Extend /dev/mapper/vgubuntu-swap_1
sudo lvextend -l +100%FREE /dev/mapper/vgubuntu-swap_1
sudo  lvs
sudo mkswap /dev/mapper/vgubuntu-swap_1

# Close encrypted partition
sudo vgchange --activate n vgubuntu
sudo cryptsetup luksClose encrypted

# Reboot and check
df -h
free -h

# Reference: https://sleeplessbeastie.eu/2020/07/29/how-to-expand-swap-partition-after-system-installation/