What does 'http over unix socket' mean in the docs?

From the OOD docs: Architecture — Open OnDemand 3.0.3 documentation

Looking at [19], doesn’t ‘http over unix socket’ imply that the processes are running on the same OS/machine? But in this instance the web node running apache and the compute node running RStudio server are different?

Additionally, what’s the rationale for [19] being an unsecure connection?

Thanks

Apache talks to the a usesrs’ PUN over unix sockets because they are on the same machine.

You’re right in that proxying to an origin server like Rstudio it is over real tcp sockets because Rstudio is on another machine.

We haven’t figured out how to make secure connections in a user context (i.e., SSL/TLS without privilege escalation).