dhclient
is the Dynamic Host Configuration Protocol (DHCP) Client one would use to allow a client to connect to a DHCP server.
$ sudo nano /etc/rc.local
#!/bin/bash
dhclient
exit 0
$ sudo chmod 755 /etc/rc.local
$ sudo systemctl enable rc-local
$ sudo systemctl restart rc-local
$ sudo systemctl status rc-local
I have a bunch of machines running 16.04 (which will be going EOL in a month and a half) that need to be upgraded.
I have run into this issue with ipoib on another machine running 20.04 and am now dreading the upgrade.
In all the years since I started using linux, I never encountered a situation where /etc/network/interfaces either bugged out or wasn't capable of doing what I needed it to. I just don't understand why this needed to be changed! Its things like this that give me second thoughts about ubuntu.