Currently, the usual way to communicate with VM instances in the cloud from outside is ssh. This is okay for most uses, but a) does not work when you mess up with the guest's ability to network and b) requires a free floating IP.
I wonder if, for qemu/kvm instances, it would be possible to use virtio-serial possibilities : from the guest, it is seen as a serial port, and from the outside, it is seen as a UNIX socket, or as something else. It is fast, as it does not go through virtualization and device drivers.
Maybe that exists already, or people are already working on it. Maybe that's what they already use for the "console" in the cloud dashboard (or do they use VNC?). I did not investigate much yet. That seems to be a complicated hackweek project, so perharps it will not get past the investigation phase.
If it succeeds, it will have an immediate appication for SLEnkins cloud backend (virtio already works for the local backend).
This project is part of:
Hack Week 12 Hack Week 14