Symptoms

While installing Parallels Cloud Server 6.0 on the screen of initial network configuration network adapters are set to Automatic (DHCP) configuration method.
If one changes the method to Disabled and saves the settings the adapter is reset back to Automatic (DHCP).

Cause

It is known issue with Parallels Cloud Server 6.0 installer.

Resolution

After clicking Next and getting to the next screen switch to text console using CTRL-ALT-F2 and turn off the unneeded interfaces:
~# ifdown eth1