How to create custom filesystem partitions (/var, /home/, /var/log etc) on a AWS EBS disk during boot process using hashicorp packer

Question

To elaborate, I would like to partition the root disk and create separate partitions for /var, /var/log, /home etc. as part of the AMI build process and create a custom image. I do not want all the filesystems to be part of /. I would like to know if this can be accomplished using packer in a straight forward way instead of exporting and importing OVA disks/images.