Configure gunicorn with 2 gevent workers

[lorenyu]

Ticket

N/A

Changes

• Set num workers to 2
• Set guincorn worker class to gevent
• Reset memory back to infra template's default of 512 mb

Context

We recently hit more deploys where the service would never reach a healthy state. Upon further investigation, this article (https://pythonspeed.com/articles/gunicorn-in-docker/) suggests that when running gunicorn in a Docker context, the number of workers should not scale with the number of CPUs. The article also

A few other articles and gunicorn's own docs recommend that the gevent worker class is used instead of the default sync (synchronous) worker class. This allows things like database calls or network class to allow the worker to switch to another thread while waiting on I/O.

https://docs.gunicorn.org/en/latest/design.html,
https://medium.com/@danieldng/use-gevent-when-your-gunicorn-worker-is-waiting-for-data-180efef96367,
https://stackoverflow.com/questions/69372896/gunicorn-with-gevent-performance-gain

Testing

Deploy from this branch