Bash script that extend the root filesystem non-interactively and without rebooting the system.

autoextend-rootfs.sh

# Get the root filesystem
FS_TYPE=$(df -T / | grep -v Filesystem | awk '{print $2}')
FS_DEVICE=$(df -T / | grep -v Filesystem | awk '{print $1}')

# Get VG and LV from the root filesystem
VG=$(lvdisplay $FS_DEVICE | grep "VG Name" | awk '{print $3}')

# Get the disk and partition number
DISK=$(pvs | grep $VG | awk '{print $1}' | rev | cut -d/ -f1 | rev | sed 's/[0-9]*//g')
PART=$(pvs | grep $VG | awk '{print $1}' | rev | cut -d/ -f1 | rev | sed 's/^[^0-9]*//')

# Print summary
echo -e "\e[34m --> Summary:\e[0m"
echo -e "\e[34m --> Filesystem: $FS_TYPE\e[0m"
echo -e "\e[34m --> Device: $FS_DEVICE\e[0m"
echo -e "\e[34m --> Volume Group: $VG\e[0m"
echo -e "\e[34m --> Disk: $DISK\e[0m"
echo -e "\e[34m --> Partition: $PART\e[0m"

echo -e "\e[34m --> Make a rescan of the connected disks.\e[0m"
echo 1 | tee /sys/block/$DISK/device/rescan

echo -e "\e[34m --> Clean partition table - Use espect as there is only an interactive cli.\e[0m"
/usr/bin/expect<<EOF
spawn  fdisk /dev/$DISK
match_max 100000
expect "Command (m for help): "
send -- "w\r"
expect eof
EOF

echo -e "\e[34m --> Extend the last partition - Use espect as there is only an interactive cli.\e[0m"
/usr/bin/expect<<EOF
spawn fdisk /dev/$DISK
match_max 100000
expect "Command (m for help): "
send -- "d\r"
expect "Partition number *: "
send -- "\r"
expect "Command (m for help): "
send -- "ne\r"
expect "Partition number *: "
send -- "\r"
expect "First sector *: "
send -- "\r"
expect "Last sector, *: "
send -- "\r"
expect "Do you want to remove the signature? *: "
send -- "n\r"
expect "Command (m for help): "
send -- "t\r"
expect "Partition number *: "
send -- "\r"
expect "Partition type (type L to list all types): "
send -- "lvm\r"
expect "Command (m for help): "
send -- "w\r"
expect eof
EOF

echo -e "\e[34m --> Extend physical volume.\e[0m"
pvresize /dev/$DISK$PART

echo -e "\e[34m --> Extend logical volume.\e[0m"
lvextend -l +100%FREE $FS_DEVICE

echo -e "\e[34m --> Extend filesystem.\e[0m"

if [ $FS_TYPE == "xfs" ]; then
  xfs_growfs $FS_DEVICE
elif [ $FS_TYPE == "ext4" ]; then
  resize2fs $FS_DEVICE
else
  echo -e "\e[31m --> Filesystem $FS_TYPE not supported.\e[0m"
fi