[LEDE-DEV] Why does multiple instance dnsmasq work with jails but not without?

[John Crispin]

On 18/05/2016 08:24, Daniel Dickinson wrote:
> Hi all,
> 
> I had a patch that I submitted to the openwrt list sometime back that
> launched multiple instances of dnsmasq, so long as the instances were
> either tied to specific, non-overlapping, interfaces, or used different
> dns port, but at least in the case of different interfaces it only
> worked (to my dismay) if jails were in use.  Without jails only a single
> instance of dnsmasq would start.
> 
> Does anyone know why this is?
> 
> (The use case is to serve a guest vlan with a dnsmasq instance that
> forced the to use the opendns familyshield filter (since the point of
> guest vlan is you don't necessarily know how far to trust the people on
> the guest vlan (for a separate wifi SSID)).
> 
> Regards,
> 
> Daniel

it probably checks for a pid file or similar to see if it is already
running. inside a jail it essentially only runs once as it is a
container. so i would guess its pid file of proc table related.

	John