The article describes a number of parameters that can be used to control and sandboxes processes launched by systemd. One of those existing parameters is (e.g.)

The article describes a number of parameters that can be used to control and sandboxes processes launched by systemd. One of those existing parameters is (e.g.) CapabilityBoundingSet= which allows you to configure (i.e. limit) the set of Linux capabilities that the process has. The article describes how the author's company has contributed a few new parameters like ProtectSystem=strict which gives the process a completely read-only view of the file system, and ProtectKernelModules=yes which prevents the process from loading kernel modules. The underlying clear and stable interface used to accomplish these things is the Linux kernel, and another service manager could provide the same features. Systemd has a configuration file format for expressing how to launch processes (which is what I'm describing above). Another service manager could parse and understand that format, if it wanted, in the same way that systemd supports SysV init scripts and classic ways of managing service lifecycle like "service foo restart" alongside its new command systemctl.