systemd quickstart

Source:
https://fedoraproject.org/wiki/SysVinit_to_Systemd_Cheatsheet
https://wiki.ubuntu.com/SystemdForUpstartUsers
http://wiki.nginx.org/FedoraSystemdServiceFile

Start/stop/reload a service:
service foo start   # or
systemctl start foo

service foo stop   # or 
systemctl stop foo

service foo restart   # or 
systemctl restart foo

Reload a service using reload signal:
service foo reload

See if service is running:
service foo status   # or 
systemctl status foo

See tree listing of all services:
systemctl status

See job log: 
sudo journalctl -u foo -f

Enable a service (to start on boot):
systemctl enable foo

Disable a service:
systemctl disable foo

Service Definition Directory:
/lib/systemd/system/

Example Nginx Service: /lib/systemd/system/nginx.service 

[Unit]
Description=The nginx HTTP and reverse proxy server
After=syslog.target network.target remote-fs.target nss-lookup.target

[Service]
Type=forking
PIDFile=/run/nginx.pid
ExecStartPre=/usr/sbin/nginx -t
ExecStart=/usr/sbin/nginx
ExecReload=/bin/kill -s HUP $MAINPID
ExecStop=/bin/kill -s QUIT $MAINPID
PrivateTmp=true

[Install]
WantedBy=multi-user.target


Links:
https://scottlinux.com/2014/12/08/how-to-create-a-systemd-service-in-linux-centos-7/