Hacker News Reader

Comment by dabeeeenster | Hacker News Reader

Is there a way to dynamically auto-scale hosts? One of my app has very bursty traffic, and would require scaling from 2 to 10 host servers and then back down over a period of several hours. I can't see this referenced in the docs? I can see you can scale processes but that's not increasing host resources available, right?

View on HN

Flynn itself doesn't communicate with infrastructure APIs currently, but you could hook this up so that there is a base set of three servers that are always running and then an autoscaling group that watched your metrics or a schedule and added/removed servers.

I'd be happy to explain this more on IRC if you're interested (#flynn on Freenode).

Thanks for the reply. Is this something that you have planned in the future?

This aspect is a really big part of Heroku/AppEngine/Elastic Beanstalk and saves me a tonne of money each month due to the auto-scaling that we get (we're on AppEngine). Is there a reason projects like Flynn have not tackled it? Or is it just a question of time?

Yeah, it's definitely something we want to support in the future. Autoscaling requires building some components that are aware of and can communicate the underlying infrastructure APIs (AWS, GCP, Azure, DigitalOcean, OpenStack, etc.) combined with app/host metrics. It's just a matter of putting the implementation effort. We'll get there eventually.

Great stuff - thanks - good luck!

> Is there a reason projects like Flynn have not tackled it? Or is it just a question of time?

Like most useful production software, coming up with industrial-grade implementations is harder than it looks. The tricky part is picking the right basic metric.

CPU load is often a bit misleading.

maybe machine learning is useful here?

Probably overkill when the metrics are so easy to gather.

I think old-school SPC techniques will take us a lot of the way.

And even before that, asking people what they already watch is good too.

Reply on news.ycombinator.com