Most of you have probably always faced the question of which solution to use for your virtualization needs in order to build a personal lab for playing around. The two most common ones seen so far would most probably end up being Cisco VIRL (cloud and offline/your server versions) and Unetlab/EVE-NG . There are other variants related more or less to Eve-NG that also seem to do partially the job ( GNS3 ) but we won’t be talking about them here. Purpose is to show how to modify the templates of Unetlab in order to add the Juniper VMX phase 2, to show how one can debug Unetlab errors when trying to start your virtual devices (in order to figure out what the right parameters to put in the template are) and also add new options in the HTML interface (VMX with dual RE for example).