On Fri, Aug 22, 2008 at 02:14:11PM +0200, Julius Volz wrote: > On Fri, Aug 22, 2008 at 1:23 PM, Sven Wegener <sven.wegener@xxxxxxxxxxx> wrote: > >> He :) Imagine an old kernel on the backup receiving new messages and > >> not understanding them. How could we at least handle that situation > >> gracefully (without totally confusing the older kernel)? We'd need to > >> do it in a way that old features are still communicated in the same > >> way. E.g., v4-only connection syncs still use the same message format, > >> but once you use v6 entries, an unused flag or the 'reserved' field in > >> ip_vs_sync_conn is used. A v6 message would still confuse an older > >> kernel then, but a user would already notice that ipvsadm can't > >> configure the v6 services on the older kernel, so that's not too bad. > > > > If that's a problem, we can easily change the communication port and even > > completely redesign the protocol this way, without having old kernels > > getting confused about the data they get. We might lose the ability to > > sync between different versions, but in the end this is just the > > connection synchronziation and both systems should be running the same > > version. We could also keep the old communication port for some time, if > > that's really needed. > > Yes, starting from scratch on another port sounds like a good idea. > Losing sync ability totally isn't as bad as confusing an older kernel > with new messages, so I hope it's not necessary to keep the old > baggage around? That does sound like a nice idea. I think that is important that we don't confuse older kernels. I guess the only time that ineroperability would be important is when upgrading kernels, where you might want to take the master ldirector down to upgrade it, then the standby. > > Is there enough motivation for doing this though before having a > cleaned-up minimal v6 version without the sync daemon? This is where > I'm currently a bit stuck with... any help is appreciated :) IPv6 without sync is fine by me. Its certainly much better than no IPv6. Lets tackle sync a bit later. -- To unsubscribe from this list: send the line "unsubscribe lvs-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
