ZFS-JAIL(8) System Manager's Manual ZFS-JAIL(8)

Attaches and detaches ZFS filesystems from FreeBSD jails. A ZFS dataset can be attached to a jail by using the “zfs-jail jail” subcommand. You cannot attach a dataset to one jail and the children of the same dataset to another jail. You can also not attach the root file system of the jail or any dataset which needs to be mounted before the zfs rc script is run inside the jail, as it would be attached unmounted until it is mounted from the rc script inside the jail. To allow management of the dataset from within a jail, the jailed property has to be set and the jail needs access to the /dev/zfs device. The quota property cannot be changed from within a jail. See jail(8) for information on how to allow mounting ZFS datasets from within a jail.
A ZFS dataset can be detached from a jail using the “zfs-jail unjail” subcommand.
After a dataset is attached to a jail and the jailed property is set, a jailed file system cannot be mounted outside the jail, since the jail administrator might have set the mount point to an unacceptable value.

zfs jail jailid|jailname filesystem

zfs unjail jailid|jailname filesystem

zfs jail jailid filesystem
Attaches the specified filesystem to the jail identified by JID jailid. From now on this file system tree can be managed from within a jail if the jailed property has been set. To use this functuinality, the jail needs the allow.mount and allow.mount.zfs parameters set to 1 and the enforce_statfs parameter set to a value lower than 2.
See jail(8) for more information on managing jails and configuring the parameters above.
zfs unjail jailid filesystem
Detaches the specified filesystem from the jail identified by JID jailid.

jail(8), zfsprops(8)
December 9, 2019 FreeBSD