Hi Takeuchi-san, On Wed, Aug 04, 2010 at 12:13:24AM +0900, Sohgo Takeuchi wrote: > > Hi simon, > > From: Simon Horman <horms@xxxxxxxxxxxx> > | > > On Mon, Aug 02, 2010 at 06:35:49PM +0900, Sohgo Takeuchi wrote: > >> > >> Hi, > >> > >> I have been working on improving IPv6 support of ldirectord > >> for a few weeks. I would like to hear your opinion or ideas > >> about how to write ldirectord.conf. > > > > A tricky topic, thanks for thinking it through. > > > >> Q1. Should ldirectord support an IPv6 hostname in ldirectord.conf? > >> > >> A manual of ldirectord says that a hostname can be written > >> in "virtual", "real", "fallback" and so on. Current > >> implementation of ldirectord handles the hostname as only > >> IPv4. It partially supports IPv6, and can write only IPv6 > >> addresses. But it does not have a way to write a hostname as > >> IPv6. Because there is no way to distinguish between IPv4 > >> and IPv6. Should ldirectord support an IPv6 hostname in > >> ldirectord.conf? > >> > >> Q2. If the answer of Q1 is yes, how do you want to write? > >> > >> [Candidate 1] Adding a new keyword like a "ipversion". > >> A default value of "ipversion" is 4 (IPv4). > >> > >> fallback=fallback.example.com > >> fallback6=fallback.example.com > >> virtual=virtual.example.com:daytime > >> real=real1.example.com:daytime gate > >> real=10.10.10.10:daytime gate > >> > >> virtual=virtual.example.com:daytime > >> ipversion=6 > >> real=real1.example.com:daytime gate > >> real=[2001:db8::10]:daytime gate > >> > >> This way cannot handle a global "fallback" variable. We must > >> have a way to distinguish between IPv4 and IPv6 when a > >> hostname is specified in the global "fallback" variable. To > >> achieve this, there is a way to add a new variable of > >> "fallback6". Any other good ideas? > > > > This "fallback" problem seems to be the most difficult issue. > > > >> [Candidate 2] Adding new keywords of "virtual6" and > >> "fallback6". > >> > >> "virtual6" is an IPv6 version of "virtual". If a hostname > >> and an IP address are specified in the "virtual6" line and > >> in its section, they are treated as an IPv6 address and the > >> hostname will be resolved into an IPv6 address. > >> > >> "fallback6" is just a global variable. It cannot be > >> specified in a virtual section. If no "fallback" in a > >> "virtual6" section is defined, the variable of "fallback6" > >> will be used. If "fallback" in the "virtual6" section is > >> defined, it is treated as an IPv6 address. > >> > >> > >> fallback=fallback.example.com > >> fallback6=fallback.example.com > >> virtual=virtual.example.com:daytime > >> real=real1.example.com:daytime gate > >> real=10.10.10.10:daytime gate > >> > >> virtual6=virtual.example.com:daytime > >> real=real1.example.com:daytime gate > >> real=[2001:db8::10]:daytime gate > >> > >> This way breaks a backward compatibility. Current ldirectord > >> can write an IPv6 address in a "virtual" line. But this way > >> cannot. > > > > I'm not particularly concerned about backwards compatibility here, > > IPv6 for ldirectord is pretty green. > > That's good. > > >> [Candidate 3] Completely separate IPv4 and IPv6 using > >> "hoge6" keywords. > >> > >> Adding new keywords which denote IPv6. These keywords can > >> handle IPv6 only and have a name "hoge6". > >> > >> fallback=fallback.example.com > >> fallback6=fallback.example.com > >> virtual=virtual.example.com:daytime > >> real=real1.example.com:daytime gate > >> real=10.10.10.10:daytime gate > >> > >> virtual6=virtual.example.com:daytime > >> real6=real1.example.com:daytime gate > >> real6=[2001:db8::10]:daytime gate > >> fallback6=localhost:daytime > >> > >> This way is very similar to [Candidate 2]. But it is > >> consistent and easy to read. A demerit is a bit redundant? > > > > I like candidate 3. Yes, it is redundant, but it is also very clear > > and consistent. > > Yes. > > I have implemented [candidate 3]. Now it works good. Great, once you've finished your testing please post the patch. > > N.B: I think that all of the proposals would fwmark services without > > any extra magic. > > Oh, thank you. I have not considered fwmark. I think so too as > you say. -- 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
