systemd

How can I use systemd user services to handle policies (like what to start and stop when my internet connection comes and goes) on my tiny Linux palmtop?

I want systemd to start a service when a USB device is plugged in and stop it when i remove it.

With a stateless Twisted app you can scale by adding more instances. Unless you are explicitly offloading to subprocesses you will often have spare cores on the same box as your existing instance. But to exploit them you end up running haproxy or faking a load balancer with iptables. Are there any other options?