You may need to look into nginx upstream’s generic hashing (aka key hashing). Basically, upstream load balances via a client-provided key of your choosing, instead of ip address. I’ve never tried setting this up with Meteor but it could (hopefully) be as simple as generating a random key (say 1–5) and setting it in a header that upstream can read from. I think this could be a better solution than Meteor Cluster right now — I’m not sure Cluster is being maintained. Galaxy may also have something more sophisticated built in. More details here: