"Error: An architecture is required" on compose VM screen

[Anton Smith]

On a freshly installed MAAS 3.1 (using the tutorial), it is not possible to create any VMs. The architecture box is empty, and a red message states: Error: An architecture is required.

One image is downloaded (arm64). There are also reports from other users that this is preventing them from followoing the tutorial, and it is likely it's a regression since they state it works when downgrading to 3.0.

I think that if this is preventing creation of VMs with LXD then this is critical.

[Anton Smith (anton5mith)]

logs.

Also:
lxc query /1.0 | jq .environment.architectures
To start your first instance, try: lxc launch ubuntu:20.04

[
  "aarch64",
  "armv7l"
]

[Alberto Donato (ack)]

Looking at logs, the issue seems to be that the LXD server is too old (probably 4.0.8, which is the default on focal):

Please upgrade your LXD host to 4.16 or higher to support the following extensions: custom_block_volumes

[Alberto Donato (ack)]

Currently, when creating VM hosts from the API, failures from discovery are not fatal. This is intended to allow authentication to fail as certificates might not be yet trusted when adding the vmhost.

This ends up also trapping other kinds of error (such as the required extensions check above), because they're all PodProblem errors.

We should differentiate errors and still fail on this kind of errors.

[Jerzy Husakowski (jhusakowski)]

The error reported by LXD should likely be exposed to the operator to aid in troubleshooting.