Parameters should be allowed to be blank
There are many valid uses for a blank parameter (say, overriding $sudo_users for a host ). However foreman does not accept a blank, and if given "" it returns "\"\"" when used as a external node provisioning tool.
I tried removing the :value checks in in app/models/parameters.rb and it accepts into the database empty values. However it still doesn't work adding a parameter with no value to a host: it doesn't reject it but it doesn't save it either.
#2 Updated by Jisakiel Kiel about 10 years ago
I just checked in my templates... I mainly use it for defining base configs for a whole "zone" (say, sudo_users=["sysadmin1", "sysadmin2"], netbackup=["server1", "server2"] or time_servers=["x.y.z.t"] ), and then overriding it for specific hosts or zones (say, "zone_devel" without backup servers and with diferent sudo_users - in my particular case, sudo_users= and then sudo_users_nopasswd=["whomever"]).
Hope it helps clarifying my use cases...