Christopher Juckins

5 Oct 2021

Sometimes trying to boot into Ubuntu 20 from VirtualBox just results in a black screen with blinking cursor. The last known version of VirtualBox to work was a "test" version, VirtualBox-6.1-6.1.27_146688_test_el7-1.x86_64.rpm but now it fails.

I then installed VirtualBox-6.1-6.1.27_147252_test_el7-1.x86_64.rpm and the VM started up.

• Maybe the VirtualBox RPM just needed to be uninstalled and then reinstalled?

For all notes below, the new Ubuntu 20 VM has been installed and tested. Also migrated Unifi controller to it.

Upgrade 18.04 to 20.04

• After following these steps and booting into new kernel, machine would not start
• Booted into old kernel, and ran an update for new packages. New kernel was downloaded and installed.
• Had a new kernel not been available, I suspect reinstalling the original kernel that was failing would have fixed the problem

Fix /swapfile

Change hostname

Gmail SMTP on Ubuntu 20

• Install postfix and choose "Internet site"
• Accept suggested FQDN
• Don't add another user for /etc/aliases (root is already there)
• For comma-separated list of domains, accept defaults
• Accept defaults for everything else, such as synchronous mail, network blocks, etc.
• Follow rest of instructions
• Send test message

Disable firewalld on Ubuntu: https://www.cyberciti.biz/faq/linux-disable-firewall-command/