I second using runit. We use runit to be able to use the same service definitions inside docker, on a VM or bare metal.
If you've ever tried to use systemd inside docker to bring up a couple of services, you would know the hoops you have to jump through to get it working.
(I understand that docker wasn't invented to run multiple services in the one container, but sometimes it can't be avoided and simplifies app deployment vastly I.e, using CI to test your service actually starts up as per its definition: just run up a quick docker image with runit and a service definition file)
If you use systemd, you can use standard packages from your distro to run up services inside a container. That's basically the only reason I considered it.
If you've ever tried to use systemd inside docker to bring up a couple of services, you would know the hoops you have to jump through to get it working.
(I understand that docker wasn't invented to run multiple services in the one container, but sometimes it can't be avoided and simplifies app deployment vastly I.e, using CI to test your service actually starts up as per its definition: just run up a quick docker image with runit and a service definition file)