On Fri, Feb 11, 2022 at 08:32:27PM +0100, Matus UHLAR - fantomas via Dnsmasq-discuss wrote: > > > On 2/10/22 22:33, Chris Green wrote: > > > > As per the subject when does dnsmasq [re]read the leases file? > > > On Fri, Feb 11, 2022 at 12:16:52AM +0100, Petr Menšík wrote: > > > When it starts. It has own data stored in-memory and just rewrites lease > > > file. It would not read any new leases from it if some other service > > > pushed them there. If dnsmasq is restarted, it starts a new process. It > > > has to read all configuration all again, which has to be done for leases. > > On 11.02.22 09:01, Chris Green wrote: > > So does that mean there's no way to 'warm start' an instance of dnsmasq > > with a set of leases? > > as Petr said, when dnsmasq starts, it reads the leases file. > not after. > > > > > I am experimenting with my backup DHCP/DNS strategy and I have just > > > > stopped my dnsmasq server and started another listening on the first > > > > dnsmasq server's IP address. It's working OK'ish. However the new > > > > dnsmasq server doesn't (of course) know the name/IP pairs that the old > > > > dnsmasq server had in its memory. > > > > > > > > If I had copied the dnsmasq.lease file across from the old server to > > > > the new one would that help? Is there some way to tell dnsmasq to > > > > reload its memory from the file? If dnsmasq is restarted (e.g. by > > > > systemd) does it read the dnsmasq.leases file? > > > Surely when dnsmasq is stopped and then started it reads it's previous > > leases file so that it still knows the names/IPs of systems that it > > has provided IPs for. So if I copy that leases file to another system > > and start a copy of dnsmasq there (with same configuration as the one > > it's replacing) won't it read that leases file? > > since it reads leases file on start, copying them to second system and > starting dnsmasq there would cause reading the leases file. > > however, copying it to system with running dnsmasq would cause losing that > file. > > If you want dhcp synchronization, better use isc-dhcpd or kea-dhcpd. > > for manual (or semi-automatic) transition copying leases file could work.
Yes, thanks all, I think I understand (the bits I need anyway). -- Chris Green _______________________________________________ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
