控制正在運行ngnix是通過發送信號來完成，主要有以下一些信號

nginx –s stop ：Stops the daemon immediately (using the TERM signal).
nginx –s quit ：Stops the daemon gracefully (using the QUIT signal).
nginx –s reopen ：Reopens the log files.
nginx –s reload ：Reloads the configuration

nginx -t

nginx –g "timer_resolution 200ms"; 指定新的配置項

2. 將Nginx作為系統服務運行（System Service）

為了讓Ngnix隨系統啟動，需要將它設置為系統服務

• System V

System V中系統服務是由init進程來管理，系統服務分為不同的級別（Runlevel State）：

centos 6 /etc目錄中有不同級別服務對應的啟動腳本，這些目錄中腳本都是軟鏈接到/etc/init.d目錄

編寫sysv script ，系統服務啟動腳本通常在系統啟動，service httpd start ，/etc/init.d/httpd start 時被調用

將Nginx做成System V需要3個步驟

1.編寫Sysv 腳本: /etc/init.d/nginx

#!/bin/sh
#
# nginx - this script starts and stops the nginx daemon
#
# chkconfig:   - 85 15
# description:  Nginx is an HTTP(S) server, HTTP(S) reverse #               proxy and IMAP/POP3 proxy server
# processname: nginx
# config:      /etc/nginx/nginx.conf
# config:      /etc/sysconfig/nginx
# pidfile:     /var/run/nginx.pid

# Make sure to properly indicate the full path of your Nginx binary and conf. file here
nginx="/usr/local/nginx/sbin/nginx"
prog=$(basename $nginx)
NGINX_CONF_FILE="/usr/local/nginx/conf/nginx.conf"
pid_file="/usr/local/nginx/logs/nginx.pid"

get_pid(){
    cat "$pid_file"
}

is_running(){
    [ -f "$pid_file" ] && ps $(get_pid) > /dev/null 2>&1
}


start() {
    if [ ! -x $nginx ];then
        echo "$nginx is not executable.."
        exit 3
    fi

    if [ ! -f $NGINX_CONF_FILE ];then
        echo "$NGINX_CONF_FILE is not exist"
        exit 4
    fi

    if is_running;then
        echo "$prog is Already Running..."
    else
        echo -n $"Starting $prog: "
        $nginx -c $NGINX_CONF_FILE
        retval=$?
        if [ $retval -ne 0 ];then
            echo "Unable to start $prog"
            exit 5
        fi
        echo "$prog Started"
    fi
}

stop() {
    if is_running;then
        echo -n $"Stopping $prog: "
        kill -s QUIT "$(get_pid)"
        retval=$?
        if [ $retval -ne 0 ];then
            echo "Unable to stop $prog"
        fi
        echo "$prog Stopped"
    fi
}

restart() {
    configtest || return $?
    stop
    sleep 1
    start
}

reload() {
    configtest || return $?
    echo -n $"Reloading $prog: "
    killproc $nginx -HUP
    RETVAL=$?
    echo
}

force_reload() {
    restart
}

configtest() {
  $nginx -t -c $NGINX_CONF_FILE
    RETVAL=$?
    echo
}

force_reload() {
    restart
}

configtest() {
  $nginx -t -c $NGINX_CONF_FILE
}

status() {
    if is_running;then
        echo "Running"
    else
        echo "Stopped"
        exit 1
    fi
}


case "$1" in
    start)
        $1
        ;;
    stop)
        $1
        ;;
    restart|configtest)
        $1
        ;;
    reload)
        $1
        ;;
    status)
        $1
        ;;
    *)
        echo $"Usage: $0 {start|stop|status|restart|reload|configtest}"
        exit 2
esac

2.將nginx加入到系統默認啟動級別中

[[email protected] ~]# chkconfig nginx on

3. 檢查nginx 是否在對應啟動級別中（在對應的rc3.d中有軟鏈接）
[[email protected] ~]# chkconfig --list nginx
Nginx 0:off 1:off 2:on 3:off 4:on 5:on 6:off

• Systemd

CentOS 7的服務systemctl腳本存放在：/usr/lib/systemd/，有系統（system）和用戶（user）之分，即：/usr/lib/systemd/system ，/usr/lib/systemd/user

每一個服務以.service結尾，一般會分為3部分：[Unit]、[Service]和[Install]，具體內容如下：

[Unit]
Description=nginx
Documentation=http://nginx.org/en/docs/After=network.target  remote-fs.target nss-lookup.target

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


[Install]
WantedBy=multi-user.target

1. NGNIX 學習系列-基礎