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. > [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. N.B: I think that all of the proposals would fwmark services without any extra magic. -- 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
