Q&A: Sun exec ponders OpenSolaris, Linux (ComputerWorld)

Yes, the extra probes are already OSS. DTrace is already OSS (CDDL), as is the whole Solaris
kernel, including ZFS.

The OpenSolaris OS is mostly OSS, except for a few programs. Work is underway to eliminate
that (for all I know, there could already be a distro that ships the CDDL kernel with a 100%
OSS userland).

http://www.opensolaris.org/os/downloads/

The packages available for OpenSolaris tend to be crufty (old, not much selection if you are
into 'new' tools such as nginx or git.)