Jails are FreeBSD’s most legendary feature: known to be powerful, tricky to master, and cloaked in decades of dubious lore. Deploying jails calls upon every sysadmin skill you have, and more—but unleashing lightweight virtualization is so worth it.
gManZboy writes "Poul-Henning Kamp, a FreeBSD committer, has an article up about BSD Jails as part of Queue's special report on virtual machines. He describes BSD's interesting 'semi-permeable' approach to VMs, and the importance of security in VM architectures. The article is co-written by Robert Watson, a DARPA principal investigator in the Host Intrusion Protection (HIP) Research Group at Evaluation of containers as a virtualisation alternative into to BSD \jails" in 2000  and Solaris Containers in 2005  providing a more complete set of ne grained resource controls. This led to VM like features such as saving state, and Running Jitsi-Meet in a FreeBSD Jail Jun 19, 2020
20 Years of FreeBSD Jails :: FreeBSD Presentations and Papers
I created two jails in one FreeBSD host. I installed PHP, Apache in one jail and MySQL Server in another. All these components working fine in their own jail. My target is to host a PHP application which will communication with MySQL which located in another jail. For these I need to establish connection between these jails.
Dec 17, 2018 How To Upgrade FreeBSD Jail ( OS Level Virtualization May 06, 2017 FreeBSD Jails the hard way - GitHub Pages