[emerg]: getpwnam(“nginx”) failed

Nginx 错误与解决方法

[TOC]

## 1. 问题一
### 1.1. 问题描述

> [emerg]: getpwnam(“nginx”) failed

### 1.2. 分析原因

在nginx安装配置中是用nginx用户和nginx组来启动服务，但系统中没有nginx用户与nginx用户组

### 1.3. 解决方法

+ 创建对应nginx用户

```Shell
useradd -s /sbin/nologin -M nginx
```

+ 重启nginx

```Shell
/usr/local/nginx/sbin/nginx -s reload
```

<hr/>

## 2. 问题二

### 2.1. 问题描述

>“nginx: [emerg] unknown directive "set_real_ip_from" in /usr/local/nginx/conf/nginx.conf:50 nginx: configuration file /usr/local/nginx/conf/nginx.conf test failed”

### 2.2. 原因分析

nginx缺少了realip模块

### 2.3. 解决办法

+ 进入到nginx解压包目录

```Shell
cd /usr/local/nginx-1.15.12
```

+ 添加realip模块
 + 注意nginx安装的目录，复制时记得修改成自己安装的目录

```Shell
./configure --prefix=/usr/local/nginx --with-http_realip_module
```
+ 重新编译和安装nginx

```Shell
make && make install
```

+ 重启nginx

```Shell
/usr/local/nginx/sbin/nginx -s reload
```

<hr/>

## 3. 问题三

### 3.1. 问题描述

>“nginx [error] open() nginx.pid failed No such file or directory”

### 3.2. 解决方法

#### 3.2.1. 方式一
进入nginx安装目录，查找是否有nginx.pid文件如果存在执行下面的命令

```Shell
# 启动nginx
sudo nginx -c /usr/local/nginx/nginx.conf
# 进入到nginx安装目录后重启nginx
nginx -s reload
```

#### 3.2.2. 方式二
在方式一中没有找到nginx.pid文件，这时去修改nginx.conf中被注释 #pid   logs/nginx.pid，将注释去除并修改路径为/usr/local/nginx/logs/nginx.pid

```Shell
# 进入nginx目录
cd /usr/local/nginx/conf
# 编辑配置文件去除注释的 #pid
vim nginx.conf
```

修改完nginx.conf配置文件后，在 /usr/local/nginx 目录下创建 logs 目录

```Shell
# 创建logs目录
mkdir /usr/local/nginx/logs
# 重启nginx
/usr/local/nginx/nginx -s reload
```

<hr/>

## 4. 问题四

### 4.1. 问题描述

> nginx报错Failed to restart nginx.service Unit not found

### 4.2. 解决方法

+ 在根目录下执行

```Shell
vim /etc/init.d/nginx
```

+ 在打开的文件下插入下面的代码

```Shell
#!/bin/sh
# nginx - this script starts and stops the nginx daemin
#
# chkconfig:   - 85 15

# description:  Nginx is an HTTP(S) server, HTTP(S) reverse \
#               proxy and IMAP/POP3 proxy server

# processname: nginx
# config:      /usr/local/nginx/conf/nginx.conf
# pidfile:     /usr/local/nginx/logs/nginx.pid

# Source function library.

. /etc/rc.d/init.d/functions

# Source networking configuration.

. /etc/sysconfig/network

# Check that networking is up.

[ "$NETWORKING" = "no" ] && exit 0

nginx="/usr/local/nginx/sbin/nginx"

prog=$(basename $nginx)

NGINX_CONF_FILE="/usr/local/nginx/conf/nginx.conf"

lockfile=/var/lock/subsys/nginx

start() {
    [ -x $nginx ] || exit 5
    [ -f $NGINX_CONF_FILE ] || exit 6
    echo -n $"Starting $prog: "
    daemon $nginx -c $NGINX_CONF_FILE
    retval=$?
    echo
    [ $retval -eq 0 ] && touch $lockfile
    return $retval
}

stop() {

echo -n $"Stopping $prog: "
    killproc $prog -QUIT
    retval=$?
    echo
    [ $retval -eq 0 ] && rm -f $lockfile
    return $retval
}

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

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

force_reload() {
    restart
}

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

rh_status() {
    status $prog
}

rh_status_q() {
    rh_status >/dev/null 2>&1
}

case "$1" in
    start)
        rh_status_q && exit 0
        $1
        ;;
    stop)
        rh_status_q || exit 0
        $1
        ;;
    restart|configtest)
        $1
        ;;
    reload)
        rh_status_q || exit 7
        $1
        ;;
    force-reload)
        force_reload
        ;;
    status)
        rh_status
        ;;
    condrestart|try-restart)
        rh_status_q || exit 0
            ;;
    *)
        echo $"Usage: $0 {start|stop|status|restart|condrestart|try-restart|reload|force-reload|configtest}"
        exit 2
esac
```

+ 保存好上面的文件后进入/etc/init.d目录，然后执行下面的命令

```Shell
# 进入目录
cd /etc/init.d
# 设置文件权限
chmod 755 /etc/init.d/nginx
# 增加nginx服务
chkconfig --add nginx
# 启动nginx服务
service nginx start
```