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. > 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. -- Sohgo Takeuchi -- 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
