In this tutorial we will go over the installation of docker in FreeNas (if using jails is not enough). The first step will be to install a host for docker in a virtual machine. In the documentation for FreeNas they propose to use Ubuntu. My actual version of FreeNAS is FreeNAS-11.3-U4.1.(now TrueNAS CORE 12). The video tutorial can be found here https://hometinylab.blogspot.com/2021/01/follow-up-on-using-docker-on-truenas.html . The major job will be to install a virtual machine on the FreeNAS platform. Select Virtual Machines in the FreeNAS menu. In the list you will see the existing docker instance running. Know click on the ADD button and we will create a second one for this tutorial. Step 1 Because we are using Ubuntu 20.04 has guest operating system we will select linux . Know we need to name the machine, for this tutorial it will be dockerblog . It is always handy to use the description field docker on Ubuntu for blog tutorial . All what follows we will keep has is. Click Next