How to run docker stack in Privileged mode

I am trying to run apache inside my docker container. but it is only running in a stand alone container which I am running in privileged mode. Now I want to run same in Swarm cluster in a docker stack but I am getting following error while checking httpd status with "systemctl status httpd"

> System has not been booted with systemd as init system (PID 1). Can’t operate.
** > Failed to connect to bus: Host is down**

I have tried using the flag => “privileged: true” in my yml file but then I am getting this:

> Ignoring unsupported options: privileged

I am using version 3.1 in my yml file and
DockerCE 20.10.0
Docker-compose 1.21.2

How can I run a docker stack in privileged mode?