These are the notes of a training course on systemd I gave as part of my work with Truelite.
.mount and .swap units
Describe mount points similarly as what /etc/fstab, but with more
functionality and integration with the dependency system.
It is possible to define, for example, a filesystem that should be mounted only when the network is available and a given service has successfully started, and a service that should be started only after a given filesystem has been successfully mounted.
At boot, systemd uses systemd-fstab-generator
to generate mount and swap units from /etc/fstab, so that the usual fstab
configuration file can still be used to configure the file system layout.
See man systemd.mount, and
man systemd.swap.
See systemctl --all -t mount and systemctl --all -t swap for examples.