I would push rate limiting to the load balancer, HAProxy or Nginx, but that's just me. If you have a round-robin LB in front you just set each instance to limit at 1/nodes rate, that way you don't have to share any state.

If you're load balancing on IP hash you can set each instance to limit at full rate and not worry about it.

Shared state in rate limiting becomes a bottleneck very quickly. If you're trying to mitigate spam/DDOS you could easily get 100,000 requests a second. You're going to max out your shared state db way faster than 10gig lines