Add a --force-content-source option

[olardit-sg]

When creating a new host, in certain cases, we want to force the content source value to be the registration capsule. As a matter of fact, satellite is not always setting this value, but it's needed in some remote execution configurations. As discussed with @fcami it's usefull to workaround this bug : https://bugzilla.redhat.com/show_bug.cgi?id=1570808

PS: I'm not respecting the too-many-statements pylint rule but I can't fix it without splitting the create_host function. As there are already some pylint exceptions in the code, let me know if you want me to add this one too, or if I need to split the function

[sideangleside]

I am curious as to why this is needed and whether the remote_execution_global_proxy option has been tried. That option provides Search for remote execution Capsule outside of the proxies assigned to the host. If locations or organizations are enabled, the search will be limited to the host's organization or location.

This might be useful.

[olardit-sg]

Yes I tried the remote_execution_global_proxy option, but I had the following limitations:

• My locations are not fine-grained enough, so all the capsules defined in one location may not be able to reach all servers.
• If multiple capsules can potentially connect on a server, it means that I need to deploy the ssh keys of all the capsules on all the servers. For this to work I need to maintain an external list of all the capsule ssh keys and use the options of #253 . I don't think it will be very reliable in my organization. And furthermore, if I deploy a new capsule in a location I need to update all the servers of this location with the ssh key of the new capsule. This will be a pain to maintain.

All that to say, I think it's more straightforward to use the registration capsule for remote execution as we have nothing to maintain outside of satellite. That's true that I'm loosing some resiliency as I will have only one capsule available fore remote execution, but if the capsule is down, I won't be able to get content from it too. And since, most of the use cases of remote execution will be be to install or update packages, even if remote execution works I won't be able to get the content.

[fcami]

I think this is reasonable, that is, if Locations do not really match the actual deployment the best course of action is to fall back to the Content-Source capsule only, not the Satellite.

@akofink @evgeni @sideangleside do you need @olardit-sg to fix his code to make pylint happy about the too-many-statements rule, or can we make another exception?

[evgeni]

I'm fine with exceptions here

[akofink]

I'm also fine with an exception. We can tell pylint to ignore, right?