wizbal

wizbal

Magically autoconfigured HTTP load balancer written in Go.

wizbal takes the Host header, strips the suffix given by -host and appends the suffix given by -domain. It asks DNS for SRV records with that resulting name and uses the returns host/port pairs as backend pool for load balancing.

This is just a proof of concept with a simple health check and on-demand (but cached) dns resolution, put together in a few hours as a Hacker Time project. Thanks to Grégoire for suggesting the name.

Usage

1. Expose your backends as SRV records under some domain: srv.example.com
2. Setup a wildcard DNS entry for serving client requests, pointing to wizbal: app.example.com
3. Fire up wizbal: ./wizbal -domain=srv.example.com -host=app.example.com

Let say you have some backends under my-service.srv.example.com. Now you can access http://my-service.app.example.com:8080

TODO

• Cache SRV names and refresh regularly to avoid doing on-demand resolving