Description of problem:

This is to avoid bad tool usage as currently its possible to change the hostname with hostnamectl and then execute katello-change-hostname which leads to the error:

Error: smart_proxy not found
Couldn't find default Capsule id
Failed 'hammer -u admin -p changeme --output json capsule info --name old-hostname' with exit code 70


Version-Release number of selected component (if applicable):

Satellite 6.2.14
Satellite 6.2.15

How reproducible:

Change satellite hostname with hostnamectl and then run katello-change-hostname

Steps to Reproduce:

1. hostnameclt set-hostname katello.example.com
2. katello-change-hostname katello.example.com -u admin -p XXX (will fail with above)

Changing to the old hostname with hostnamectl so katello-change-hostname can pass:

3. hostnamectl set-hostname test2.example.com
4. katello-change-hostname katello.example.com -u admin -p XXX (will pass)

Mongo will contain old hostname:
5. > db.event_listeners.find()
{ "_id" : ObjectId("5b0ff0b0226fa42c34df85b1"), "notifier_config" : { "url" : "https://test2.example.com/katello/api/v2/repositories/sync_complete?token=....


Actual results:

katello-change-hostname will run when hostname was already changed with hostnamectl which produces error.

Expected results:

Add check to find out if new hostname used with katello-change-hostname is matching with current hostname from hostnamectl. It should not match, if it does it should error out and not proceed further.