I have been trying to get a preseed configuration working for a few days and have finally gotten to the point where it mostly works. However, the last logical volume in the partitioning takes up the remaining space in the volume group, irrespective of settings. It appears to be the exact same issue as a previous bug.

I have copied my config for your reference.

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=904184

By design, partman-auto allocates all remaining free space in the disk
or VG to the last partition regardless of the specified minimum and
maximum sizes. See create_partitions() in lib/auto-shared.sh. Whether
this is a bug or not is open to debate.

When using guided partitioning with LVM, you can specify the amount of
volume group space to use in partman-auto-lvm/guided_size, either as an
absolute size or a percentage of available space. Else, a workaround is
to create a last dummy partition and delete it afterwards.

Pascal Hambourg <pascal@plouf.fr.eu.org> writes:

You may find this element of my preseeding framework useful:

https://hands.com/d-i/preseed/classes/partition/_/unfilled/

which is the bit of a recipe, and the preseed & late script bits, to
create and then remove such a partition.

Cheers, Phil.

P.S. The rest of the framework is probably overkill if you have already
got your preseed script done, but it's got quite a lot of examples
hidden in there that may be of interest:

https://hands.com/d-i

BTW If you're wondering how the above "_/unfilled" bit gets used, one
can specify it as a dependency, usually in partition classes, thus:

https://hands.com/d-i/classes/partition/multi/spare/filter

which means that if one specifies e.g. `partition/multi/spare` as a
class that you're using for the install, and you'll get a multi
partition layout with a spare bit.

Cheers, Phil.