Junos OS with upgraded FreeBSD was first introduced in Junos OS Release 15.1 running on bare metal.
In Junos OS Release 16.1, with the release of virtualized Routing Engines RE-MX-X6, RE-MX-X8, and RE-PTX-X8, Junos OS with upgraded FreeBSD could run as a guest virtual machine (VM) on a Linux VM host.