Description of problem:
We have fought with this bug on several occasions and it seems to regress regularly :-)

If I perform an offline installation (tested with Live image), with ethernet cable unplugged, the installed system has ONBOOT=no in the wired ethernet NM configuration file. That causes the installed system to never automatically connect to the wired network even when the cable is plugged in.

This is a big problem. I often attend events where I help students to install Fedora. Usually that's done offline. That triggers this bug. And wired internet doesn't work for these students when they come home. Since they are not familiar with Fedora, there's almost no chance that they will find "Connect automatically" checkbox to fix this. Depending on their DE, they might not even know they just need to enable the device. In their eyes, wired network simply does not work.

Together with Vratislav Podzimek we have identified the problem to be related to this code:
https://git.fedorahosted.org/cgit/anaconda.git/tree/pyanaconda/installclasses/fedora.py#n44
The device is set to autoconnect only if it has link up during installation.

And also this:
https://git.fedorahosted.org/cgit/anaconda.git/tree/pyanaconda/network.py#n250
There are two problems here:
a) The NM configuration files are created even if they are not needed. Creating the config file even when the user has not requested any changes is error-prone, because it might cause some problems in the future. Let's say some IPv6 setting default changes in the future. If there was no config file on the disk, the new default would simply apply. If there is already a config file, the user has to detect this (common users won't) and modify it manually. There is a reason why systemd is moving towards "works out of the box even without any config files" approach.
b) The code says
> For server, default auto connections will be turned off in NetworkManager.conf.
But still, the code disables autoconnect explicitly for every single interface present on the system. Why does Anaconda choose not to honor NM defaults (i.e. autoconnect on)? If server has some specific needs (like disabling autoconnect globally), that can be done in NetworkManager.conf and you don't need to do it for all devices on all products (e.g. Workstation).

So, please, make autoconnect work again, even for offline installation. I'm talking mainly about Fedora Workstation, I don't mind if Server has some specific needs and behaves differently.

My recommendation would be:
1. Do not create default NM config files for every device. If the user manually configured devices using NetworkManager prior to installation or from Anaconda itself, the config file will be automatically created by NM. Otherwise, don't touch it.
2. Do not disable autoconnect for every device. If you need a different behavior for Server, do it in NetworkManager.conf.
3. Now you can get rid of the code in FedoraBaseInstallClass.setNetworkOnbootDefault().

If that doesn't work for you for some reason, at least modify FedoraBaseInstallClass.setNetworkOnbootDefault() to automatically enable *all interfaces* on boot by default for Fedora Workstation.

Version-Release number of selected component (if applicable):
anaconda 21.48.7-1

How reproducible:
always

Steps to Reproduce:
1. unplug cable from desktop or laptop (this can't be done in a VM)
2. install Fedora Live
3. reboot into the system
4. plug the cable in
5. see that your internet doesn't work
6. Enter NetworkManager and find "Connect automatically" checkbox, it's disabled

Actual results:
wired interface is disabled by default

Expected results:
wired interface is enabled by default

Additional information:
Below I attach anaconda log files from a system installed offline.