On 26/05/12 10:24, Vincent Cadet wrote:
This active-passive scheme shouldn't need any dnsmasq
changes, and
arranging to monitor server instances and start a new
one when an
existing one goes down is a solved problem: it's
exactly what heartbeat
does.
Building a heartbeat harness to run dnsmasq
active-passive and
replicated tyrant (or another database) sure looks like
a useful thing
to try, IMHO.
What if there be a heartbeat link in dnsmasq through which the active
dnsmasq would stream changes (or the whole block of data) to the
passive instance along with keep-alive probes?
That has attractions: Both dnsmasq instances could provide DNS service
at all times, and whichever was "master" could provide DHCP, whilst the
"slave" just keeps it's database up-to-date. The main problem with this
is the "split brain" scenario, where both instances are up, but they
can't talk to each other because the network between them is
partitioned. In that case both acting as masters for their half of the
network is fine, the problem comes when connectivity returns and the
lease databases have to be reconciled....
Something similar to
Postgres streaming replication in fact. An interruption in the stream
for more than a programmed delay would then be interpreted as a
fail-over request. The link would be a socket, serial link,
whatever.
Worth thinking about....
Simon.
_______________________________________________
Dnsmasq-discuss mailing list
Dnsmasq-discuss@lists.thekelleys.org.uk
http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
