Ubuntu 18.04 AMI with "ubuntu-desktop" pkg fails to connect (networking)

Question

The problem can be duplicated easily with the following steps:  
- launch ubuntu 18.04 instance  
- apt install ubuntu-desktop  
- create an AMI from this instance  
- launch a new instance from AMI and fail to connect via ssh  
  
Looking at the system log, it is obvious that the network interface ens5 was not started properly.  Its status is shown as "down".  See image attached.  
  
Any ideas? The original instance still works fine in terms of networking.

Answer

It turns out ifupdown pkg brought in by ubuntu-desktop is conflicting with the new netplan in some wired way, I suppose.  After "apt purge ifupdown", things are fine now.

Ubuntu 18.04 AMI with "ubuntu-desktop" pkg fails to connect (networking)

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