morph exec --on="*" should run the command on all hosts asynchronously

[cole-h]

For example, running morph exec --on="*" ./network.nix nix-collect-garbage on a network where all hosts have a large amount of garbage to collect, this could take a very long time until it moves to the next host.

[andir]

Just adding my 2cent here: I would love this feature but we must make sure to not "hide" deployment failures and not to short-circuit the deployments. I have a few machines that sometimes fail during reloading of systemd services (startup race condition with dns resolver & lets encrypt).