No network after upgrade to 16.04 and how to fix

After upgraded to Ubuntu 16.04 from 14.04, my server network stop functioning (cannot ping gateway or anything...). I tried several things but none of them works (especially this one). So I ran these command to check my server's network status:

$ sudo ifconfig

=> There's only the loopback interface show up. Where is my eth0?

2. Then, I check the network status:

$ sudo service networking status

It said it could not bring up the eth0 interface because it find no interface name eth0 on the server.

3. Finally, I tried and "the thing" shown up:

$ sudo ifconfig -a


4. And because I statically assigned the interface's configuration so I have to go in and change it to reflect the new name of the interface:

$ sudo nano /etc/network/interfaces

auto ens192
iface ens192 inet static