debug note-- nginx php-fpm : Error:The page you are looking for is temporarily unavailable.

1.在ubuntu下安装配置nginx, mysql, php

安装步骤：

参考：https://www.digitalocean.com/community/tutorials/how-to-install-linux-nginx-mysql-php-lemp-stack-on-ubuntu-12-04#

具体摘抄如下：

About Lemp

LEMP stack is a group of open source software to get web servers up and running. The acronym stands for Linux, nginx (pronounced Engine x), MySQL, and PHP. Since the server is already running Ubuntu, the linux part is taken care of. Here is how to install the rest.

Setup

The steps in this tutorial require the user to have root privileges. You can see how to set that up in the Initial Server Setup Tutorial in steps 3 and 4.

Step One—Update Apt-Get

Throughout this tutorial we will be using apt-get as an installer for all the server programs. On May 8th, 2012, a serious php vulnerability was discovered, and it is important that we download all of the latest patched software to protect the virtual private server.

Let's do a thorough update.

sudo apt-get update

Step Two—Install MySQL

MySQL is a powerful database management system used for organizing and retrieving data

To install MySQL, open terminal and type in these commands:

sudo apt-get install mysql-server php5-mysql

During the installation, MySQL will ask you to set a root password. If you miss the chance to set the password while the program is installing, it is very easy to set the password later from within the MySQL shell.

Once you have installed MySQL, we should activate it with this command:

sudo mysql_install_db

Finish up by running the MySQL set up script:

sudo /usr/bin/mysql_secure_installation

The prompt will ask you for your current root password.

Type it in.

Enter current password for root (enter for none):
OK, successfully used password, moving on...

Then the prompt will ask you if you want to change the root password. Go ahead and choose N and move on to the next steps.

It’s easiest just to say Yes to all the options. At the end, MySQL will reload and implement the new changes.

By default, a MySQL installation has an anonymous user, allowing anyone
to log into MySQL without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.

Remove anonymous users? [Y/n] y
 ... Success!

Normally, root should only be allowed to connect from 'localhost'.  This
ensures that someone cannot guess at the root password from the network.

Disallow root login remotely? [Y/n] y
... Success!

By default, MySQL comes with a database named 'test' that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.

Remove test database and access to it? [Y/n] y
 - Dropping test database...
 ... Success!
 - Removing privileges on test database...
 ... Success!

Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.

Reload privilege tables now? [Y/n] y
 ... Success!

Cleaning up...

Once you're done with that you can finish up by installing PHP.

Step Three—Install nginx

Once MySQL is all set up, we can move on to installing nginx on the VPS.

sudo apt-get install nginx

nginx does not start on its own. To get nginx running, type:

sudo service nginx start

You can confirm that nginx has installed an your web server by directing your browser to your IP address.

You can run the following command to reveal your VPS's IP address.

ifconfig eth0 | grep inet | awk '{ print $2 }'

Step Four—Install PHP

To install PHP-FPM, open terminal and type in these commands. We will configure the details of nginx and php details in the next step:

sudo apt-get install php5-fpm

Step Five—Configure php

We need to make one small change in the php configuration.Open up php.ini:

 sudo nano /etc/php5/fpm/php.ini

Find the line, cgi.fix_pathinfo=1, and change the 1 to 0.

cgi.fix_pathinfo=0

If this number is kept as 1, the php interpreter will do its best to process the file that is as near to the requested file as possible. This is a possible security risk. If this number is set to 0, conversely, the interpreter will only process the exact file path—a much safer alternative. Save and Exit. We need to make another small change in the php5-fpm configuration.Open up www.conf:

 sudo nano /etc/php5/fpm/pool.d/www.conf

Find the line, listen = 127.0.0.1:9000, and change the 127.0.0.1:9000 to /var/run/php5-fpm.sock.

listen = /var/run/php5-fpm.sock

Save and Exit.

Restart php-fpm:

sudo service php5-fpm restart

Step Six—Configure nginx

Open up the default virtual host file.

sudo nano /etc/nginx/sites-available/default

The configuration should include the changes below (the details of the changes are under the config information):

UPDATE: Newer Ubuntu versions create a directory called 'html' instead of 'www' by default. If /usr/share/nginx/www does not exist, it's probably called html. Make sure you update your configuration appropriately.

 [...]
server {
        listen   80;

        root /usr/share/nginx/www;
        index index.php index.html index.htm;

        server_name example.com;

        location / {
                try_files $uri $uri/ /index.html;
        }

        error_page 404 /404.html;

        error_page 500 502 503 504 /50x.html;
        location = /50x.html {
              root /usr/share/nginx/www;
        }

        # pass the PHP scripts to FastCGI server listening on the php-fpm socket
        location ~ \.php$ {
                try_files $uri =404;
                fastcgi_pass unix:/var/run/php5-fpm.sock;
                fastcgi_index index.php;
                fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
                include fastcgi_params;

        }

}
[...]

Here are the details of the changes:

• Add index.php to the index line.
• Change the server_name from local host to your domain name or IP address (replace the example.com in the configuration)
• Change the correct lines in “location ~ \.php$ {“ section

Save and Exit

Step Seven—Create a php Info Page

We can quickly see all of the details of the new php configuration.

To set this up, first create a new file:

sudo nano /usr/share/nginx/www/info.php

Add in the following line:

<?php
phpinfo();
?>

Then Save and Exit.

Restart nginx

sudo service nginx restart

You can see the nginx and php-fpm configuration details by visiting http://youripaddress/info.php

Your LEMP stack is now set up and configured on your virtual private server.

2. 按照上述文章介绍的安装步骤安装之后，通过浏览器访问php文件得到502页面：The page you are looking for is temporarily unavailable.

检查nginx的error.log文件: 发现错误：connect to php5-fpm.sock failed (Permission denied)，

检查php5-fpm.sock的权限得到other的权限为：---

解决方法：

参考：http://stackoverflow.com/questions/23443398/nginx-error-connect-to-php5-fpm-sock-failed-13-permission-denied

具体摘抄如下：

1. Open /etc/php5/fpm/pool.d/www.conf

2. Uncomment all permission lines, like:

   listen.owner = www-data
   listen.group = www-data
   listen.mode = 0660
   

3. Restart fpm - sudo service php5-fpm restart

     Note: if your webserver runs as as user other than www-data, you will need to update the www.conf file accordingly