Side-car Deployment Model
It's a curious technique. Kubernetes makes it possible, although I think this did exist before Kubernetes, it just was never that popular. I would not really call this an anti-pattern. Instead it is a curious pattern. Often people would put something in a container, such as a log aggregator, and then have main application container talk to it via HTTP ?? What was the point of going through the trouble of putting it in the same pod then?