sudo: unable to resolve host

2014-11-30 11:58:18 +0000

Attempting to sudo bash, I was confronted with:

ubuntu@ip-172-30-0-195:~$ sudo bash
sudo: unable to resolve host ip-172-30-0-195

This is because the hostname doesn’t appear in /etc/hosts, so edit it as follows:

127.0.0.1 localhost
172.30.0.195 ip-172-30-0-195

# etc.