Running Node.js App with cluster module is meaningless in Heroku?

Question

Heroku can run

Web Dynos

and

Worker Dynos

so that Web Dynos take care of routes

and worker W

Answer 1

This is an old question, thought I should update to a more complete answer.

According to this table on their documentation

• 1X Dynos have 1 cluster
• 2X Dynos have 2 clusters
• PX Dynos have 12 clusters

So, assuming that you are using 1X dynos, it won't be necessary to implement clusters. If you are using the other ones, it is a good idea to do so.

The number of clusters can be found on the WEB_CONCURRENCY environment variable.

Answer 2

That's very good news to me, i assumed that a dyno is just one core. I actually wrote and open sourced a small but very nicely made cluster setup (backed by redis and job queue)

https://bitbucket.org/jeveloper/nodejscluster

Answer 3

I've found that it actually worth to use cluster module

because each dyno has 4 CPU cores.

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Reference: http://www.quora.com/Heroku/How-powerful-is-one-Heroku-dyno