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Improve gratuitous ARP compatibility #172
In #123, @mleklund pointed to https://ihrachyshka.com/2017/05/26/the-failure-part-4-summary/ , a blog series from OpenStack folks on debugging problems with their ARP-based failover implementation. They found a whole bunch of things, and some of them are relevant to our interests.
Short version: Linux kernels before ~4.11 have a whole set of different bugs that break gratuitous ARP in various ways. Kernels after that have been fixed, so the gratuitous ARP that MetalLB is doing right now should work perfectly, and update all ARP cache entries within 1-2s of failover.
To improve compatibility in the face of buggy kernels, we can do 2 things
This bug is to track those changes.