How to install Nginx and PHP-FPM on Ubuntu

Nginx is a very popular web server in recent years. It is very well known for being used as a high performance web server, a reverse proxy server, or even a load balancer. Some differences Nginx has from Apache:

- No built in PHP support (mod_php).
- Apache is process based while Nginx is event based.
- Modules in Nginx are compiled directly into the binary while Apache has installable modules that can be enabled or disabled quickly
- Nginx configuration files are a series of includes for each sites configuration, whereas Apache has global settings and a companion virtual host with overrides for customization.  So this means there is no override file like Apache's .htaccess in Nginx.
- There are no SSLCertificateChainFile in Nginx.  Intermediate CA certificates need to be appended directly to the site's SSL certificate.

At this time, the current best practice for installing Nginx is to use Nginx’s repos directly as they will contain the most recent and stable releases of Nginx. So install the repo package for Nginx by:

# Ubuntu 12.04 and 14.04
[[email protected] ~]# nginx=stable # use nginx=development for latest development version
[[email protected] ~]# apt-get install python-software-properties
[[email protected] ~]# add-apt-repository ppa:nginx/$nginx
[[email protected] ~]# apt-get update
[[email protected] ~]# apt-get install nginx

As Nginx does not have anything to natively process PHP, install php5-fpm by:

# Ubuntu 12.04 and 14.04
[[email protected] ~]# apt-get update
[[email protected] ~]# apt-get install php5-fpm php5-cli

By default, php-fpm will be listening for connections over TCP. This is incredibly slow when Nginx and php-fpm are on the same server. So modify the php-fpm configuration from listening over TCP to using sockets by:

[[email protected] ~]# vim /etc/php5/fpm/pool.d/www.conf
...
[www]
listen = /var/run/php5-fpm.sock
...

Now set php-fpm to run as user nginx:

[[email protected] ~]# vim /etc/php5/fpm/pool.d/www.conf
...
user = www-data
group = www-data
listen.owner = www-data
listen.group = www-data
...

Back in Nginx, configure it to send any PHP requests to the php-fpm socket inside of the http{} block:

[[email protected] ~]# vim /etc/nginx/nginx.conf
http {
...
upstream php5-fpm-sock {
     server unix:/var/run/php5-fpm.sock;
}
...
}

Now that Nginx and php-fpm are configured, setup your first site:

[[email protected] ~]# mkdir -p /var/www/vhosts/example.com
[[email protected] ~]# vim /etc/nginx/conf.d/example.com.conf
server {
     listen 80;
     server_name example.com www.example.com;

     root /var/www/vhosts/example.com;
     index index.php index.html index.htm;

     access_log /var/log/nginx/example.com-access.log;
     error_log /var/log/nginx/example.com-error.log;

     location ~ \.php$ {
          expires off;
          try_files $uri =404;
          include /etc/nginx/fastcgi_params;
          fastcgi_pass php5-fpm-sock;
          fastcgi_index index.php;
          fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
     }

     # caching of files
     location ~* \.(js|css|png|jpg|jpeg|gif|ico)$ {
          expires max;
          log_not_found off;
     }
}

#server {
#      listen 443 ssl;
#      server_name example.com www.example.com;
#
#      root /var/www/vhosts/example.com;
#      index index.php index.html index.htm;
#
#      access_log /var/log/nginx/example.com-ssl-access.log;
#      error_log /var/log/nginx/example.com-ssl-error.log;
#
#      ssl_certificate /etc/pki/tls/certs/YYYY_example.com.crt;
#      ssl_certificate_key /etc/pki/tls/private/YYYY_example.com.key;
#
#      ssl_session_timeout 5m;
#
#      # Use PCI compliant SSL protocols and ciphers
#      ssl_protocols SSLv3 TLSv1;
#      ssl_ciphers HIGH:!kEDH:!ADH:!EXPORT56;
#      ssl_prefer_server_ciphers on;
#
#      location ~ \.php$ {
#           expires off;
#           try_files $uri =404;
#           include /etc/nginx/fastcgi_params;
#           fastcgi_pass php5-fpm-sock;
#           fastcgi_index index.php;
#           fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
#      }
#
#      # caching of files
#      location ~* \.(js|css|png|jpg|jpeg|gif|ico)$ {
#           expires max;
#           log_not_found off;
#      }
# }

Finally, restart Nginx and PHP-FPM to apply the changes

# Ubuntu 12.04 and Ubuntu 14.04
[[email protected] ~]# service php5-fpm restart
[[email protected] ~]# service nginx restart

NOTE : There is no SSLCertificateChainFile in nginx. CA Certs need to be appended to the certificate for the domain.

Troubleshooting

If you see a page that says ‘The page you are looking for is currently unavailable’, you’ll find Nginx is having trouble getting data from php-fpm (while using a socket). Make sure that the socket you specify in the nginx.conf and the listen line in www.conf pool file for PHP-FPM match.

If you get a ‘File Not Found’ page only on php pages (when using a TCP port for php-fpm) you can check the nginx logs, and you’ll probably see an error indicating it couldn’t connect on the port. Its possible this could be happening if you need to move the root and index definitions out of a location block (if they are defined there). This is because the php section has it’s own location, the documents won’t try to be found using definitions in the domain ‘location /’ block.

Nginx stub_status module

Like the Apache mod_status module, Nginx also has a module that can provide you with realtime data regarding its stats. While its not as detailed as Apache mod_status, the data is still useful, especially if you are using Nginx as a load balancer.

First, confirm that Nginx was compiled with the HttpStudStatusModule. If you installed this via yum or apt-get, it should have it:

[[email protected] ~]# nginx -V 2>&1 | grep -o with-http_stub_status_module
with-http_stub_status_module

To enable the module, set the following configuration:

[[email protected] ~]# vim /etc/nginx/conf.d/nginx_status.conf
server {

    listen 80 default_server;
    access_log off;
    server_name _;
    server_name_in_redirect off;
    root  /var/www/html;

        location /nginx_status {
                # Enable Nginx stats
                stub_status on;
                # Disable logging for stats
                access_log   off;
                # Security: Only allow access from authorized IP's
                allow 127.0.0.1;
                allow 192.168.1.100;
                # Deny everyone else
                deny all;
        }

}

Now navigate your browser to:

http://serverip/nginx_status

The results will look something like this:

Active connections: 1 
server accepts handled requests
 1 1 1 
Reading: 0 Writing: 1 Waiting: 0

Here is what these numbers mean, taken directly from Nginx’s documentation:

# Active connections
The current number of active client connections including Waiting connections.

# accepts
The total number of accepted client connections.

# handled
The total number of handled connections. Generally, the parameter value is the same as accepts unless some resource limits have been reached (for example, the worker_connections limit).

# requests
The total number of client requests.

# Reading
The current number of connections where nginx is reading the request header.

# Writing
The current number of connections where nginx is writing the response back to the client.

# Waiting
The current number of idle client connections waiting for a request.

Apache mod_status module

The Apache mod_status module is one that I don’t hear about much anymore, but it is something that can be very useful when troubleshooting high CPU or Memory usage with Apache.

Taken it directly from the Apache documentation, mod_status provide you with details such as:

- The number of worker serving requests.
- The number of idle worker.
- The status of each worker, the number of requests that worker has performed and the total number of bytes served by the worker.
- A total number of accesses and byte count served.
- The time the server was started/restarted and the time it has been running for.
- Averages giving the number of requests per second, the number of bytes served per second and the average number of bytes per request.
- The current percentage CPU used by each worker and in total by all workers combined.
- The current hosts and requests being processed.

Setting it up is simple. It only gets a bit complicated explaining it in a single blog post for multiple operating systems as it gets stored in different places depending on which distro your using.

I’ll outline the configuration location that it needs to be placed in below:

# CentOS 6 / CentOS 7
[[email protected] ~]# vim /etc/httpd/conf.d/status.conf

# Ubuntu 12.04
[[email protected] ~]# vim /etc/apache2/conf.d/status.conf

# Ubuntu 14.04
[[email protected] ~]# vim /etc/apache2/conf-available/status.conf

Using the correct location for your distro as shown above, use the following configuration to enable mod_status. Please be sure to update the AuthUserFile line accordingly for your distro:

<IfModule mod_status.c>
#
# ExtendedStatus controls whether Apache will generate "full" status
# information (ExtendedStatus On) or just basic information (ExtendedStatus
# Off) when the "server-status" handler is called. The default is Off.
#
ExtendedStatus On

# Allow server status reports generated by mod_status,
# with the URL of http://servername/server-status
# Uncomment and change the ".example.com" to allow
# access from other hosts.
#
<Location /server-status>
     SetHandler server-status
     Order deny,allow
     Deny from all
     Allow from localhost ip6-localhost
     <IfModule mod_rewrite.c>
          RewriteEngine off
     </IfModule>
     Allow from 127.0.0.1

# On CentOS / RedHat systems, uncomment the following line
     AuthUserFile /etc/httpd/status-htpasswd

# On Debian / Ubuntu systems, uncomment the following line
#     AuthUserFile /etc/apache2/status-htpasswd

     AuthName "Password protected"
     AuthType Basic
     Require valid-user

     # Allow password-less access for allowed IPs
     Satisfy any
</Location>

</IfModule>

Once you have the configuration in place, you can secure it with a username and password, and then enable it by:

# CentOS 6 / CentOS 7
[[email protected] ~]# htpasswd -c /etc/httpd/status-htpasswd serverinfo
[[email protected] ~]# service httpd restart

# Ubuntu 12.04
[[email protected] ~]# htpasswd -c /etc/apache2/status-htpasswd serverinfo
[[email protected] ~]# service apache2 restart

# Ubuntu 14.04
[[email protected] ~]# htpasswd -c /etc/apache2/status-htpasswd serverinfo
[[email protected] ~]# a2enconf status.conf
[[email protected] ~]# service apache2 restart

Now that mod_status is enabled and working when going to http://serverip/server-status, how can it help with troubleshooting?

Lets say you look at top, and you consistently see an Apache process maxing out a CPU, or using up a ton of memory. You can cross-reference the PID of that Apache child process against the same PID that you find within the server-status page. The requests are constantly changing, so you may need to refresh the /server-status page a couple of times to catch it.

To aid in the troubleshooting as you are trying to match up pids against what is shown in top, you can have the /server-status page refresh automatically by using the following in the URL:

http://serverip/server-status?refresh=2

Once you do locate it, it may give you some idea of what client, or what types of requests, are causing the resource contention issues. Usually it is a specific web application misbehaving, or a specific client is attacking a site.

SSL terminated load balancer causing redirect loops

You have an environment that is terminating SSL on the load balancer for one reason or another. Your application, such as WordPress or Magento, is configured to force SSL. But when you go to test out the site or the admin portal, you get a redirect loop. What happened?

This is a very common issue. In most cases when you are terminating SSL at the load balancer, the load balancer will send the traffic over to your web server using HTTP. This can confuse the web application since it was expecting it to be over HTTPS, and the application will not be able to tell that the client’s browser was in fact using HTTPS, which will result in a redirect loop.

The solution to this is actually very simple. You need to ask your load balancer to send the X-Forwarded-Proto header. This can easily be done by adding a SetEnvIf directive into your .htaccess (assuming Apache here), which will set the header to be what your application was expecting.

To account for this, at the top of your site’s .htaccess file, add the following:

[[email protected] ~]# vim /var/www/vhosts/www.domain.com/.htaccess
...
# Detect the LB header and set the header accordingly for the application
SetEnvIf X-Forwarded-Proto https HTTPS=on
...

So in summary, this will prevent your application from getting confused regarding if the connection originated over HTTP or HTTPS since the load balancer is handling the SSL termination, not the server.

Apache Mod_Rewrite tutorial

Apache Mod_Rewrite provides the ability to rewrite incoming requests to different destinations. It can be a bit complicated to wrap your head around the syntax, but once you get used to it, it becomes very powerful.

Rewrite rules can be setup in 2 places, the Apache VirtualHost configuration, or within the website’s .htaccess file. Modifying the .htaccess file allows you to change the rewrite rules on the fly without restarting Apache. However it comes at a steep cost. When using an .htaccess file, each time someone visits your page, the .htaccess file must be processed. So for large rulesets, this could add a substantial CPU load on your web server.

Taken directly from Apache’s website:

You should avoid using .htaccess files completely if you have access to httpd main server config file. Using .htaccess files slows down your Apache http server. Any directive that you can include in a .htaccess file is better set in a Directory block, as it will have the same effect with better performance.

To avoid the performance penalty, I prefer to keep the rules within the Apache VirtualHost configuration. When Apache is restarted, the rules are read into memory, which allows for faster processing.

Rewrite rule example – Step by step

I prefer to learn by example. So lets take an example that is going to be slightly more complicated then it needs to be on purpose to illustrate the syntax.

All requests to http://www.domain.com should be redirected to http://192.168.1.100.  Concurrently, https should also redirect to https://192.168.1.100.

A possible solution to put into the Apache VirtualHost configuration would be:

RewriteEngine On
RewriteCond %{SERVER_PORT} ^80$
RewriteCond %{HTTP_HOST} ^domain.com$ [NC,OR]
RewriteCond %{HTTP_HOST} ^www.domain.com$ [NC]
RewriteRule ^/(.*) http://192.168.1.100/$1 [R,L]

RewriteCond %{SERVER_PORT} ^443$
RewriteCond %{HTTP_HOST} ^domain.com$ [NC,OR]
RewriteCond %{HTTP_HOST} ^www.domain.com$ [NC]
RewriteRule ^/(.*) https://192.168.1.100/$1 [R,L]

To explain some of the common regex used:

1.  ^ --> String starts with
2.  !^ --> String does not start with
3.  % --> server variable
4.  [NC,OR]  --> This means 'NC' Not case sensitive 'OR' It can either match this or the line below.  If you want it to match both rules, then just use 'NC'  Using an 'AND' statement would break the rule, as the policy already defaults to 'AND'.
5.  [R,L]  This means:  rewrite, last.  So basically it is doing the rewrite and it saying this is the last part of the condition, so end the loop.  
6.  ^/(.*) --> This means anything and everything matching the conditions above (used in this example in the rewriterule)

Easy right? Yea, I know it is not. But it makes more sense the more you have to use it. So let me explain the solution above line by line:

First, we need to enable the rewrite engine:

RewriteEngine On

Now put in the first test condition. For the purposes of this article, we are going to simplify this request by testing for anything coming in over port 80:

RewriteCond %{SERVER_PORT} ^80$

Then we need to test a condition to actually match the URL we are looking to do the rewrite on. In this case, it is domain.com. Now, you should be sure to set the ‘NC’ (non case) so we don’t break the rule if someone types in the request in capital letters. You want to test for both domain.com and www.domain.com. This is done by:

RewriteCond %{HTTP_HOST} ^domain.com$ [NC,OR]
RewriteCond %{HTTP_HOST} ^www.domain.com$ [NC]

Next we write the actual rewrite statement. This is saying, take the result of the above and point it to what we specify here. So to talk this out, it is rewriting anything that matches whats above ^/(.*) and redirecting it to the specified address. The [R,L] rewrite the url ‘R’, and end the statement as it is the last rule ‘L’.

RewriteRule ^/(.*) http://192.168.1.100/$1 [R,L]

Finally, don’t forget to apply all this to https on port 443! You use the same explanations as above for figuring this out.

Common rewrite examples

Enough of the obscene examples and explanations. Below is a bunch of common (and not so common) examples for quick reference:

Rewrite domain.com to www.domain.com:

RewriteEngine On
RewriteCond %{HTTP_HOST} !^www [NC]
RewriteRule ^(.*)$ http://www.%{HTTP_HOST}$1 [R=301,L]

Rewrite www.domain.com to domain.com:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^www.domain.com [NC]
RewriteRule ^(.*)$ http://domain.com$1 [L,R=301]

Force SSL on your domain, meaning take any http requests and redirect them to https:

RewriteEngine On
RewriteCond %{SERVER_PORT} !^443$
RewriteRule ^(.*)$ https://%{HTTP_HOST}$1 [R=301,L]

Force SSL on your domain, meaning take any http requests and redirect them to https when using an SSL terminated load balancer:

RewriteEngine On
RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteRule ^(.*)$ https://www.domain.com$1 [R=301,L]

Rewrite one domain to another:

RewriteEngine on
RewriteCond %{HTTP_HOST} ^(www.)?domain1.com [NC]
RewriteRule ^(.*)$ http://domain2.com$1 [R=301,L]

Redirect a path to a new domain:

Redirect 301 /path http://new.domain.com
Redirect 301 /otherpath/somepage.php http://other.domain.com

Rewrite page with query string to a different page and include query string. Please note, this must be in the Apache VirtualHost config, it will not work in the .htaccess.

# This will redirect www.example.com/products?sku=xxx over to www.example.com/products/sku/xxx
RewriteEngine On
RewriteCond %{REQUEST_URI} ^/products [NC]
RewriteCond %{QUERY_STRING} ^sku=(.*)
RewriteRule (.*) https://www.example.com/products/sku/%1? [R=301,L]

Rewrite page with query string, and strip query string:

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-l
RewriteCond %{REQUEST_URI} ^/pages/pages\.php$
RewriteCond %{QUERY_STRING} ^page=[0-9]*$
RewriteRule ^.*$ http://www.domain.com/path/? [R=301,L]

Force all URL’s to be lowercase. Please note, this must be in the Apache VirtualHost config, it will not work in the .htaccess.

RewriteEngine On
RewriteMap lc int:tolower
RewriteCond %{REQUEST_URI} [A-Z]
RewriteRule (.*) ${lc:$1} [R=301,L]

Exclude phpmyadmin from being rewritten by existing rules (Place this above the problem rule):

RewriteCond %{REQUEST_URI} !=/phpmyadmin

Disable TRACE and TRACK methods:

RewriteEngine On
RewriteCond %{REQUEST_METHOD} ^(TRACE|TRACK)
RewriteRule .* - [F]

Rewrite images to Cloud Files. Please note, this must be in the Apache VirtualHost config, it will not work in the .htaccess.
* Note: The RewriteRule and URL belong on the same line.

<Directory /var/www/vhosts/domain.com/content/images>
RewriteEngine On
RewriteRule ^(.*)$ http://c0000.cdn00.cloudfiles.rackspacecloud.com/$1 [R=302,L]
</Directory>

Rewrite all pages to a maintenance page

Options +FollowSymlinks
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_URI} !/maintenance.html$
RewriteRule .* /maintenance.html [L]