in short resize a partition non-interactive to its maximum size
Since using fdisk in this case is pretty complicated due to the case that non-interactive ways are probably not possible or very complicated using printf, i want to use parted resizepart for resizing a partition to its maximum size.
This can be used in scenarios like disk-resizes ( hypervisor / virtualization ). Now you need to adjust your logical volume / pv to the new size (LVM case) or you want to adjust the partition size of a normal partition.
So lets assume i want to resize partition /dev/sda1 on disk /dev/sda to its maximum possible size - how would i do this without getting asked any questions at all.
Eventhough parted /dev/sda resizepart 1 exists, it needs me to calculate and enter the maximum disk size - so how to automate this would be the next question - and the answer was the reason parted auto resize has been written.
curl -o /usr/local/bin/resize.sh https://raw.githubusercontent.com/EugenMayer/parted-auto-resize/master/resize.sh- parted 3.0 or higher (otherwise probably rename
parted resizeparttoparted resize)
Save the script above as resize.sh and make it executable
# resize the fourth partition to the maximum size, so /dev/sda4
# this is the sandbox mode, so no changes are actually done - just previewed
./resize.sh /dev/sda 4
# apply those changes
./resize.sh /dev/sda 4 apply
Since debian does not allow you to preseed a LVM configuration, which uses a disk as a pv / vg, but always force you to use a partition, you need a convinient way to resize the pv partition, so you can resize any logical volumes. It can be done using fdisk, but this needs ot be done by hand, interactive with a lot more steps ( usual delete / create / set type to Linux LVM / write / reload partition table
Assuming your pv / vg is created on /dev/sdb1 named vgdata and the LV to resize is named data and you resized your disk using your hypervisor.
Now using this script, all you do is
./resize.sh /dev/sdb 1 apply
pvresize /dev/sdb1
lvextend -r /dev/mapper/vgdata-data -l '+100%FREE'
thats it! Note, if you happen to notice -r in lvextend, yes thats pretty cool, it calls resize2fs /dev/mapper/vgdata-data for us automatically after the partition resize ( to adjust the filesystem size )