FreeBSD Crossbow

Once I started learning about containers and surrounding technologies, I heard about Solaris Zones and Crossbow. In short, zones are containers, like jails, and crossbow is something like a vnet. They say it's way more flexible and powerful. One of the things it can do is prevent you from setting up static IP. I thought that's pretty important thing and I wanted to have that. With CBSD/Reggae I'm a little closer to saying "we have it". Reggae sets up a jail named cbsd and inside it /dev/pf and DHCP server are configured in a very special way. Because DHCP process is running as dhcp user, and that user can not run pfctl, unless /dev/pf owning group is the same as DHCP process group. Luckily, devfs.rules allows one set of rules for host and other set for the jail. That means /dev/pf on host is owned by root:root while it's owned by root:unbound inside the jail and mode is 660. Of course, DHCP runs under group unbound. The reason is that unbound files from host are nullfs mounted inside the jail. That way DHCP can edit unbound zones and add leased addresses to PF table. On host, that PF table is used to configure NAT, so basically allowing jails to reach Internet.

Let's face it. What I just described is nowhere near to Solaris crossbow, but it's the closest I can get.