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Hi folks

As promised a long time ago my colleague Nik Lutz has finalized the patch for the VM that enables socket activation with Systemd. I will quickly go over what the patch is supposed to achieve, how we plan to use socket activation and what (minimal) changes are necessary.

Systemd Socket Activation:
Systemd opens a (network-) socket and waits for connections. When the first client connects the assotiated service (VM) is started. Systemd indicates via environment variable (LISTEN_FDS) that it opened a network socket.

Detailed documentation on socket activation with Systemd can be found here: http://0pointer.de/blog/projects/socket-activation.html

Our scenario for socket activation:��

At Cmsbox we have hundereds of images running on a server, all of which listen on a dedicated network port for incoming connections. The server is powerful enough to run all these processes concurrently, especially since not every image receives requests all the time.

With socket activation we could further lower the server load and free up resources for images with a high request rate. Images that don���t receive any requests for a specified amount of time can be suspended automatically and reactivated when a request comes in.