The behavior when you specify no --nodeport-addresses value in a
dual-stack cluster is terrible and we can't fix it, for
backward-compatibility reasons. Actually, the behavior when you
specify no --nodeport-addresses value in a single-stack cluster isn't
exactly awesome either...
Allow specifying `--nodeport-addresses primary` to get the
previously-nftables-backend-specific behavior of listening on only the
node's primary IP or IPs.