ESXi is bare-metal hypervisor, which supports FreeBSD.
VMware tools is an optional set of drivers and utilities that improves the interaction between the host and the guest, as well as improves performance. There are currently 3 different "flavors" of VMware Tools for FreeBSD:
- Official VMware Tools
Official tools by VMware. Easy to install. Just click the "Install VMware Tools" button in the GUI, mount the virtual CDROM, copy the tar.gz file, extract and run the installation. Requires lang/perl and misc/compat6x.
- With CURRENT (10.x), official tools and memory ballooning can produce kernel panics, mostly noted when there's no load.
- Open Virtual Machine Tools
GPL licensed tools, also from VMware. Available in ports as emulators/open-vm-tools and emulators/open-vm-tools-nox11. Installing from ports will also install several dependencies, which is a bit annoying. Contributions to the code base are accepted, but one needs to sign an agreement and send it to VMware. The FreeBSD ports are also quite outdated.
- OpenBSD vmt(4) VMware Tools driver
BSD licensed kernel level implementation of VMware Tools. With this driver several features work out of the box without the need for installing any packages/ports. vmt(4) is not available in stock FreeBSD at the moment, but a non-working FreeBSD driver is available in a projects/ branch. It may be a good starting point for porting this driver over to FreeBSD. If we want working tools out of the box in the future, this is probably the way forward.