On 3/27/25 12:23, Igor Fedotov wrote:
Hey Folks,
can anyone shed some light on the current status and plans for dual IPv4/IPv6 support in Ceph?
See this tracker: https://tracker.ceph.com/issues/65631
I know there were some work in that direction a while ago but IIUC it's never been completed. Any ideas why?
My guess is that nobody really wants to have dual-stack support. You either run IPv4 only, or IPv6, but not both. The amount of failure modes with running both IP stacks also increases dramatically. Would there be automatic fallback from one stack to the other? What stack would be preferred, and is this implemented consistently for all daemons and clients? Would you be able to run messenger v1 on IPv4, and messenger v2 on IPv6, mixed between clients? What if all daemons listen on a certain stack, with the exception for one, and that stack has an issue? Will be hard to troubleshoot. As of now there is no IPv6 testing in place (only IPv4 for now). Although we are trying to change that (Thanks to Wido den Hollander, et. al.). Try to calculate the amount of possible combinations for dual-stack setups, and then imagine the amount of testing needed to do this properly ... for what gain really? None at all if you ask me. It's 2025 ... use IPv6 and be done with it.
Is there any work in progress? Is this still considered as doable?
I'm pretty sure that it could be done at a really high price. The real question should be: should we even try.
Do we still want it? Any estimates how hard it would be?
If this is ever pursued do take into calculation the amount of testing needed. And the ability to disable it and force a single stack only. Gr. Stefan