Horizontal scaling across multiple aws regions?

[vinod-canihelp]

Hello all!
I just started using python-socketio. I use redis as the message queue to enable horizontal scaling.
Please correct me if I am wrong but this only enables scaling within an AWS region, right?
If so, what is the way to scale across aws regions? For example, how can an socketio event in us-west-2 be shared with servers in us-east-1?

[miguelgrinberg]

python-socketio does not have any limitations in terms of the deployment. As long as you deploy your message queue so that it is accessible from the two regions, the servers should be able to communicate and share events.

Whether that is a good or bad idea it is a different topic. The latency is going to be fairly high, for example. And you are going to have to put a lot of thought into securing your message queue, because I believe it is not possible to create a VPC that spans regions, so you'll be forced to send your message queue traffic over the open internet, which is quite risky.

[vinod-canihelp]

Interesting! Seems like socketio is primarily designed for single region deployments. Let me research more into it... Meanwhile I have two questions for you:

• What are your thoughts on AWS Redis Global datastore as message queue. Here's what I found in the docs:

For cluster-mode disabled, pub/sub is fully supported. Events published on the primary cluster of the primary AWS Region are propagated to secondary AWS Regions.

• If socketio is not the right solution for cross-region pub/sub, what are some options to consider?

[miguelgrinberg]

I have no experience with the global datastore service. If it is fully compatible with Redis then maybe it works, but remember what I said about latency? That was not about python-socketio, it was about the message queue. So make sure you test this under production load to make sure events are delivered within an acceptable timeframe.

Also regarding your second question, Socket.IO is much more than pub/sub. If all you want is pub/sub, then just use Redis alone. You don't need anything else.

[vinod-canihelp]

I am building a chat app. I am currently using socketio to push messages from one user to other users in the conversation. This works well for a single region. I am investigating ways to scale to multiple regions. Exposing Redis to clients is not an option.

There are other third party SaaS solutions for this. I am wondering if I can leverage socketio to solve this problem instead of switching over to other third party SaaS...

[miguelgrinberg]

Well, as I said above, python-socketio does not care where the nodes are located. So a) make sure your message queue traffic is secure to travel over the open internet, and b) evaluate if the latency increases in Redis are acceptable.