(In reply to Rich Coe from comment #13) > I didn't set up anything in systemd, cgroup or otherwise. Well, systemd tends to do many things behind your back. So I would double check the pid controller configuration for the cgroup your process belongs to. /proc/<pid>/cgroup will list all the cgroups the given pid is attached to. If there is a pid controller then check the respective cgroup and its max pid count setup. We have seen issues like that in the past.