Well, I think I came to @giacomo's conclusion. And it's not an Anaconda bug, neither a kickstart one. Maybe Anaconda has some usability issues and breaks the user's expectations ...but we can't fix them, we can only improve our docs
I ran some experiments (more details at bottom) and read some docs
When a Red Hat Enterprise Linux 7 installation finishes and the system boots for the first time, any network interfaces which you configured during the installation will be activated. However, the installation does not prompt you to configure network interfaces on some common installation paths - for example, when you install Red Hat Enterprise Linux from a DVD to a local hard drive.
When you install Red Hat Enterprise Linux 7 from a local installation source to a local storage device, be sure to configure at least one network interface manually if you require network access when the system boots for the first time.
You will also need to set the connection to connect automatically after boot when editing the configuration.
This is documented to be the "Automatically connect to this network when it is available" option:
We could add an additional installation option. Now we have interactive, unattended and centos. We could add a manual one: it would be like interactive but does not pre-set any storage and network option.
More info about Anaconda kickstart customization:
Do you remember if you set "Automatically connect to this network when it is available"?
I can't reproduce it:
- Fired a new VM in KVM, with 4 network adapters. Three of them are attached to a network with DHCP.
- Boot with interactive method.
- Anaconda enables only the interfaces with DHCP (even if our kickstart enables all of them)
- Entered the Network & Host Name section
- Disabled DHCP interfaces
- Enabled the remaining one
- Entered the "Configure" section for it
- Enabled "Automatically connect to this network when it is available" under General tab
- Set manual IP configuration method under "IPv4 settings" (IP, mask, gateway, DNS)
- Pressed "Save" button
- After a while, my settings are displayed under the main screen
- Set host name FQDN
- Clicked "Apply"
- Clicked "Done"
...the resulting system has ens3 configured as expected. I was astonished to see also the DHCP interfaces UP. I'd expect them DOWN, but this is another story...