DTrace in the zone

When the zones facility was originally developed many years ago, our focus on integrating it with respect to DTrace was firmly on the global zone: we wanted to be sure that we could use DTrace from the global zone to instrument the entire system, across all zones. This was (and remains) unique functionality — no other implementation of OS-based virtualization has the whole-system dynamic instrumentation to go with it. But as that focus implies, the ability to use DTrace in anything but the global zone was not a consideration. Fortunately, in 2006, Dan Price on the zones team took it upon himself to allow DTrace to be used in the non-global zone.