Answer by Thomas for How do you automatically set infiniband mode to connected?

Since netplan does not support the pre-up scripts, you do have two options here:

1. Get rid of netplan

   Modify /etc/default/grub and add netcfg/do_not_use_netplan=true to GRUB_CMDLINE_LINUX. Then run update-grub.

   GRUB_CMDLINE_LINUX="netcfg/do_not_use_netplan=true"

   After a reboot /etc/network/interfaces is used again.

2. Use networkd as netplan's renderer

   Basically, it is networkd-dispatcher which will provide the functionality to call scripts. A detailed description can be found here.