virtualization/kvm_check_vm and kvm_test need some documentation and error handling and proper recommends

[Daniel Manrique]

During field testing this test failed to run, and there was no indication why. When diagnosing this test it turned out the user hadn't set the CLOUD_IMAGE variable and so the script just silently exited with failure. Since this is usually run in server enviroments where we prefer to have verbose output to ease after-the-fact debugging, the test should be updated so that it is a bit more verbose about what it's doing and why it fails.

Also documenting the need to set CLOUD_IMAGE and what's a good value for it may be useful; I had to ask around to get a tip on how to set the variable, this should be documented somewhere, even if it's only in the script's comments.

[Sylvain Pineau (sylvain-pineau)]

the $CLOUD_IMAGE is a fallback if the script cannot access the network to download the one from cloud-images.ubuntu.com.
Did it was the environment of the test ? no network ?

[Daniel Manrique (roadmr)]

Oh yes, there was no network/internet access.

Can the script, then, indicate that it was unable to download the image? (just goes to the need for the script to have better logging).

[Daniel Manrique (roadmr)]

I'll set this as triaged. Work to be done: flesh out the script so it has better diagnostic output.

[Zygmunt Krynicki (zyga)]

I'm marking this as WONT FIX but please reopen if this is actively hampering anyone's work. My goal is to limit the number of open bugs to get a better idea as to what is really important.

Remember that you can always escalate bugs by contacting us in #checkbox on freenode (or #cert-infra in the internal IRC) or by responding in bugs directly.