Update OVA and AMI images to Ubuntu 20.04 LTS

[malcyon]

Updating images to Ubuntu 20.04.

Fixes #242

[malcyon]

Observations

Changing iso_url to the latest 20.04 iso causes packer to hang for 3 hours and then time out.

http://www.cdimage.ubuntu.com/ubuntu/releases/20.04/release/ubuntu-20.04.2-live-server-arm64.iso

If I start the Virtualbox GUI, I can attach to the running VM and see this error message:

FATAL: Could not read from the boot medium! System halted.

It seems like the issue is that the preseed functionality we are using to auto-answer install questions is gone in 20.04:

With 20.04 LTS, we will be completing the transition to the live server installer and discontinuing the classic server installer based on debian-installer (d-i), allowing us to focus our engineering efforts on a single codebase. The next-generation subiquity server installer brings the comfortable live session and speedy install of Ubuntu Desktop to server users. (https://discourse.ubuntu.com/t/server-installer-plans-for-20-04-lts/13631)

So, I'll probably have to add the cloud-config yaml. Not sure what other changes are in store for 20.04.

References:

• https://wiki.debian.org/DebianInstaller/Preseed
• https://www.packer.io/docs/builders/virtualbox/iso#http-directory-configuration
• https://ubuntu.com/server/docs/install/autoinstall
• https://ubuntu.com/server/docs/install/autoinstall-quickstart
• https://github.com/Praseetha-KR/packer-ubuntu

[mjknoxie]

Was the ARM ISO intentionally selected? Should it not be the amd64?

[malcyon]

Was the ARM ISO intentionally selected? Should it not be the amd64?

Yeah... I just figured that out. That's why it won't boot!! OMG.

I'm trying add in the autoinstall thing, too.