Hi Luke, On Thu, Feb 27, 2020 at 03:07:35PM +0100, Luke Seelenbinder wrote: > Hello List, > > We use SRV records extensively (for internal service discovery, etc.). > > When the patch was integrated to support a 0 weighted SRV records, I thought > that would simplify our setup, because at the time, I thought 0 weight meant > "backup server" without a "backup" flag on the server. Unfortunately for our > simplicity, that is not the case. A 0 weight means "will never be used unless > explicitly chosen". > > That leads me to my questions: > > - Is that the intended behaviors of 0 weight servers: to not function as a > backup if all other servers are down?
Yes it is! They're typically used to drain old user sessions while progressively taking a server off. Some also use them to let an overloaded server cool down for a moment with no extra session. This is completely unrelated to backup servers in fact, which have their own weights and which can even be load balanced when all active servers are dead. > - Would you (Willy?) accept a patch that used the Priority field of SRV > records to determine backup/non-backup status? Or perhaps an additional > server option to specify 0 weighted SRV records means "backup"? I suspect that it's more a property of the resolvers than the servers. I mean, if you know that you're using your DNS servers this way, this should really have the same meaning for all servers. So you shouldn't have a per-server option to adjust this behavior but a per-resolvers section. I'm personally not opposed to having more flexibility, and I even find that it is a good idea. however I'm really not skilled at all in the DNS area and Baptiste is the maintainer so I'm CCing him and will let him decide. Cheers, Willy
