Offer Ubuntu 24.04 Noble Numbat to Jetstream2 users

Problem / Opportunity Statement

Ubuntu 24.04 comes out later this month, and to save you the search, this is a numbat.

Click to expand numbat

Resolution

• Decide if/how to announce availability of the new distro on Jetstream2.
• Decide on a deprecation plan for Ubuntu 20.04, which is now approximately our second-most-popular distro (behind Ubuntu 22), and update this plan accordingly.
  • If we follow our de facto policy, we'll stop building new 20.04 images, and deprecate the extant public image, around when Ubuntu 24.04 comes out. This may be disruptive to folks who currently use it, so we may want to allow some overlap.
  • Whatever we decide to do, we should make it legible / knowable to community members.
    • One nice targeted way is emailing every user who has created an Ubuntu 20 instance in the past year, informing them that on some date, they can no longer create Ubuntu 20.04 instances.
• On/after the 24.04 release date (about April 25):
  • Update image build pipeline to build Ubuntu 24.04 images
  • Update cloud_configs.js in Exosphere so that we show a button for 24.04 when people create instances
  • Update docs site indicating that we offer 24.04, perhaps also update this tutorial.
  • Software Store - 24.04 compatible packages
  • Exosphere should support setup of Ubuntu 24.04 instances, tracked as exosphere/exosphere#1014 (closed)