[Dnsmasq-discuss] Distributed lease database on a mesh, using batman-adv alfred
gui at altermundi.net
Sat Nov 2 20:30:41 GMT 2013
Hello once again Simon,
we are giving one more iteration to this Libre-Mesh idea, this
weekend at a HackMeeting near Bilbao
i already described a bit of the "interesting" setup generated by the
firmware in my last email.
To make the mesh as distributed / resilient as possible, there's a
dnsmasq instance running on each node, with identical configuration
(i.e. everyone serves the same range to its clients, since they are all
part of a batadv link-local that enables them to roam around)
This scheme needs some kind of "lease propagation" between all
instances: not only to avoid collisions in a robust way, but also to
have cloud-wide hostname resolution (i.e. any dnsmasq will know
hostname->ip of every client, independent of which dnsmasq gave the
lease to the client)
Gioacchino did a small script to be used as a --dhcp-script, that
talks to alfred (a batadv-related daemon that propagates arbitrary
data over a link-local) and correctly populates dnsmasq lease database
on startup (since leasefile-ro makes dnsmasq call the script with "init"
it also accepts "add" actions and such, and instantly propagates leases
to the rest of the nodes.
Problem is, there's no way to update dnsmasq internal database from
outside (i.e. when alfred gets new info from another node); SIGHUP will
not make dnsmasq call dhcp-script "init", only a full restart will do,
and we'd rather not kill and respawn dnsmasq whenever a new lease is
given in any part of the cloud :P
Simon, any chance of having dnsmasq call "init" on dhcp-script (or
lua-hook, if it's simpler) when getting a SIGHUP (or another, dedicated
signal, for that matter)?
I hope my description of why that'd be highly desirable was
Hope you're having a nice weekend!
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