I use the template module to install the .service file into the /etc/systemd/system. According to this digital ocean blog post /lib/systemd/system should be reserved for packages bundled with the OS itself, and third party services should be defined in /etc/systemd/system.
With ansible’s systemd module I’d start the service with daemon_reload=yes.
Prior to Ansible 2.2: I do a systemctl daemon-reload afterward (can use an ansible handler for this if appropriate) to prod systemd to pick up the new file.
- name: install myservice systemd unit file
template: src=myservice.j2 dest=/etc/systemd/system/myservice.service
- name: start myservice
systemd: state=started name=myservice daemon_reload=yes
# For ansilble < 2.2 only
#- name: reload systemd unit configuration
# command: systemctl daemon-reload