Pulp

For most Pulp 3 installations, it seems there are two default applications that will be running: API and content. Those applications are currently set to run on 8000 and 8080 respectively.

The problem is that these are common HTTP auxiliary ports. Lots of other applications use them. If 2 daemons try to listen on the same port, even on localhost only, the daemon started earlier will block the one started later (or the one started later will not listen on the port.)

Scenarios might include:

1. A moderately skilled sysadmin sets up Pulp in a test environment. In the test environment, compliance agents (log collection, anti-virus, etc) are installed with their WebGUIs enabled. One listens on port 8080, and therefore Pulp fails to start. The sysadmin figures this out, but only after debugging why. Eventually, their effort to use Pulp takes too long, and management instructs them to shift to other higher priority / unplanned tasks.

2. A junior sysadmin has about a dozen production servers running a LOB application, and a small server to run supporting services. The supporting services, including Pulp, all must run on that 1 server due to expensive licensed software needing to be installed on every physical or virtual machine. Another important supporting service is on this machine, and listens on port 8000. The junior sysadmin is incapable of figuring out why Pulp doesn't start, and gives up on Pulp

Another reason to change the ports is that it might be more obvious for operators and developers to have the defaults next to each other in order to make it more predictable and easier to remember.

My suggestion is: 24816 (API) and 24817 (content). (Update: now 24816 (content) and 24817 (API))
These are easy to remember for technical people: Powers of 2 are 2, 4, 8, 16.
And they are unallocated to any application.

These default values need to be updated in multiple places, such as documentation.

email thread: https://www.redhat.com/archives/pulp-dev/2019-March/msg00028.html