Comment 25 for bug 1688508

Repro:
$ uvt-simplestreams-libvirt --verbose sync --source http://cloud-images.ubuntu.com/daily arch=amd64 label=daily release=xenial
$ for f in $(seq 0 40); do uvt-kvm create --memory 2048 --cpu 4 xenial-testshutdown-$f release=xenial arch=amd64 ; done

Be aware of the up to 80G memory consumption (in theory, since they idle it is more like 20G).

Run
$ sudo systemctl stop libvirt-guests

The first 10 will be shut down fine (and more correctly than before the last fix).
But if you have MORE than the PARALLEL_SHUTDOWN= value then it fails to shut down those.

This seems to be an issue with updating some variables in the script.
At least the timeout properly kicks in and ends this (which makes it no worse than pre the last change where it could forget some guests).

FYI
More easily tested with 5 guests and the config set to
PARALLEL_SHUTDOWN=2
SHUTDOWN_TIMEOUT=20

Modify as needed, then run
sudo /usr/lib/libvirt/libvirt-guests.sh stop