On Sep 16, 2009, at 9:53 PM, Ralph Castain wrote:
> WHAT: change the IPv6 configuration option to enable IPv6 if and
> only if specifically requested
> WHY: IPv6 support is only marginally maintained, and is currently
> broken yet again. The current default setting is causing user
> systems to break if (a) their kernel has support for IPv6, but (b)
> the system administrator has not actually configured the interfaces
> to use IPv6.
> TIMEOUT: end of Sept
> SCOPE: OMPI trunk + 1.3.4
> There appears to have been an unfortunate change in the way OMPI
> supports IPv6. Early on, we had collectively agreed to disable IPv6
> support unless specifically instructed to build it. This was decided
> because IPv6 support was shaky, at best, and used by only a small
> portion of the community. Given the lack of committed resources to
> maintain it, we felt at that time that enabling it by default would
> cause an inordinate amount of trouble.
> Unfortunately, at some point someone changed this default behavior.
> We now enable IPv6 support by default if the system has the required
> header files. This test is inadequate as it in no way determines
> that the support is active. The current result of this test is to
> not only cause all the IPv6-related code to compile, but to actually
> require that every TCP interface provide an IPv6 socket.
> This latter requirement causes OMPI to abort on any system where the
> header files exist, but the system admin has not configured every
> TCP interface to have an IPv6 address...a situation which is proving
> fairly common.
> The proposed change will heal the current breakage, and can be
> reversed at some future time if adequate IPv6 maintenance commitment
> exists. In the meantime, it will allow me to quit the continual
> litany of telling users to manually --disable-ipv6, and allow OMPI
> to run out-of-the-box again.