how to setup jail
--
1 Place the stuff you want to run and the stuff it needs to run somewhere on your filesystem. # host filesystem (one folder or safer zfs mount point)
2 Add some basic configuration for the jail in jail.conf # host /etc/jail.conf
3 Fire up the jail #exec it

1
~ # zfs create -p zroot/srv/jails/bsd-test01
~ # zfs set mountpoint=/srv zroot/srv
~ # fetch ftp://ftp.freebsd.org/pub/FreeBSD/releases/amd64/amd64/11.1-RELEASE/base.txz -o base-11.1-RELEASE.txz 
~ # tar xf base-11.1-RELEASE.txz -C /srv/jails/bsd-test01

2 
vi /etc/jail.conf

bsd-test01 {
        exec.start  = "/bin/sh /etc/rc";
        exec.stop   = "/bin/sh /etc/rc.shutdown";
        exec.clean;

        mount.devfs;

        path = "/srv/jails/bsd-test01";

        host.hostname = "bsd-test01.local";
}

3
~ # jail -c bsd-test01
~ # jls
~ # jexec bsd-test01