New Python relic alternative?

Question

I am looking for an alternative to a new relic that I could place on my own in Python or with a free plan like Sentry.

I already use Sentry free plan for bug tracking, and it is really necessary for our infrastructure (Django). (Getsentry.com)

I am looking for the other side, the dark side. Monitor bandwidth servers, processor, memory, and applications like Redis, Postgresql, Varnish, etc.

Munin does the job, but he is getting really old, and it’s a pain to install.