CentOS7.5下开发systemctl管理的自定义Nginx启动服务程序

 cat /usr/lib/systemd/system/sshd.service
 
 [Unit]   #<==对该系统服务描述及说明模块。
 Description=OpenSSH server daemon            #<==描述性说明。
 Documentation=man:sshd() man:sshd_config() #<==文档列表说明。
 After=network.target sshd-keygen.service     #<==服务依赖类别说明。
 Wants=sshd-keygen.service     #<==可选的依赖服务。
  
 [Service]   #<==系统服务的运行参数设置模块
 Type=notify #<==服务类型，可选有forking、notify、simple等。
 EnvironmentFile=/etc/sysconfig/sshd  #<==环境变量等的配置文件。
 ExecStart=/usr/sbin/sshd -D $OPTIONS #<==服务的启动程序。
 ExecReload=/bin/kill -HUP $MAINPID   #<==重启程序。
 KillMode=process
 Restart=on-failure
 RestartSec=42s
  
 [Install] #<==服务安装的相关设置。
 WantedBy=multi-user.target   #<==这里为设置多用户级别。可为空格分隔的列表， 表示在使用 systemctl enable 启用此单元时， 将会在对应的目录设置对应文件的软连接。
 更多说明，可参考systemd.unit、system.service文档，此不细述，都掌握了意义也不大，可以写出启动脚本即可。

 vim /usr/lib/systemd/system/nginx.service
 
 [Unit]
 Description=The nginx HTTP and reverse proxy server            #描述说明；
 After=network.target remote-fs.target nss-lookup.target        #服务依赖类别说明；
  
 [Service]
 Type=forking        #服务类型，可选有forking、notify、simple等；
 ExecStartPre=/application/nginx/sbin/nginx -t        #启动前检查配置文件是否正确；
 ExecStart=/application/nginx/sbin/nginx                #启动nginx
 ExecReload=/bin/kill -s HUP $MAINPID                #重载reload
 ExecStop=/bin/kill -s QUIT $MAINPID                    #停止服务
 PrivateTmp=true                #为服务分配独立的空间；
         
 [Install]
 WantedBy=multi-user.target        #多用户级别
 
 说明第一次启动会提示以下报错：
 [root@server nginx-1.8.]# systemctl restart nginx.service
 Warning: nginx.service changed on disk. Run 'systemctl daemon-reload' to reload units.
 Job for nginx.service failed because the control process exited with error code. See "systemctl status nginx.service" and "journalctl -xe" for details.
 
 执行下面的命令重新载入 systemd，扫描新的或有变动的单元即可：
 systemctl daemon-reload        #重新载入 systemd，扫描新的或有变动的单元

 [root@lb01 ~]# systemctl daemon-reload
 [root@lb01 ~]# systemctl stop nginx
 [root@lb01 ~]# systemctl start nginx
 [root@lb01 ~]# systemctl status nginx
 ● nginx.service - The nginx HTTP and reverse proxy server
    Loaded: loaded (/usr/lib/systemd/system/nginx.service; enabled; vendor preset: disabled)
    Active: active (running) since 五 -- :: CST; 7s ago
   Process:  ExecStart=/application/nginx/sbin/nginx (code=exited, status=/SUCCESS)
   Process:  ExecStartPre=/application/nginx/sbin/nginx -t (code=exited, status=/SUCCESS)
  Main PID:  (nginx)
    CGroup: /system.slice/nginx.service
            ├─ nginx: master process /application/nginx/sbin/nginx
            └─ nginx: worker process
 
 9月  :: lb01 systemd[]: Starting The nginx HTTP and reverse proxy server...
 9月  :: lb01 nginx[]: nginx: the configuration file /application/nginx-1.8./conf/nginx.conf syntax is ok
 9月  :: lb01 nginx[]: nginx: configuration file /application/nginx-1.8./conf/nginx.conf test is successful
 9月  :: lb01 systemd[]: Started The nginx HTTP and reverse proxy server.
 [root@lb01 ~]# systemctl restart nginx
 [root@lb01 ~]# systemctl reload nginx
 [root@lb01 ~]# systemctl stop nginx
 [root@lb01 ~]# systemctl restart nginx
 [root@lb01 ~]# systemctl enable nginx
 [root@lb01 ~]# systemctl list-unit-files|grep nginx
 nginx.service                                 enabled