Load balancing since Node v0.12.2 - cluster, pm2 or nginx

Question

With Node v0.12.2, the cluster module supports Round-Robin (RR) load balancing, which ensures load is more evenly distributed than the previous OS-level load balancing.

So now we are spoilt for choice:

1. Use the cluster module
2. Use pm2 which uses the cluster module under the hood
3. Use nginx
4. Use HAProxy

I am aware of this excellent post as well as other answers here on SO, but none have addressed the newer Cluster module with RR mode. So the question boils down to:

Judging only on their load balancing capabilities, should I use pm2 or nginx?

Answer 1

TL;DR

If it's just pm2 vs. nginx go for nginx. Better: both. Best: a even broader setup.

If you want the most mature load balancing features use HAProxy. It's do one thing best. You'll get SSL-termination, ACLs and it being very lightweight. I can't prove with numbers, but I feel it has the lowest hit on http requests. A good read is this.

If you also need to serve (at least some) static content your goto option is nginx for its superior capabilities in this field. Also of your list it's the only one to provide such a feature. Except for node itself, but doing it very poorly.

pm2 feels very heavy-weight IMO and tends to break more often. It's capabilities of process load balancing are very good and secures uptime of your node process. It abstracts cluster.

cluster feels just 'being fixed' to a bare minimum. In the past and maybe still the os-level support lead to different behaviours on different platforms. For example, bias to single processes.

My current setup is:

• HAProxy for cluster wide loadbalancing, including balancing several instances of a process per machine
• CDN for static content (e.g. Cloudinary)
• pm2 for process load balancing