Unfortunately there is not really one. I always treated jails as VM's. You could create the jails on ZFS and do a send and receive, or use something like Jenki

Unfortunately there is not really one. I always treated jails as VM's. You could create the jails on ZFS and do a send and receive, or use something like Jenkins to build and deploy. However jails are like LXC on Linux, not like docker. You could use nanoBSD in the source tree to create a minimal mostly immutable image with your application. It will still be like a VM though and need deployed somewhere (this is how i run my DNS servers at home, they are about 120MB each and can run on pretty much any VM host (or bare metal)). But docker does have that market better (hence why i have a small swarm at home to play on). There is also docker for FreeBSD, still in testing but works pretty good it you build your own native images. I build a memcached image and was running that for a while.