There is definitely a fair amount of information out there on how to get nginx running with WordPress via FastCGI.  Slicehost, my current hosting provider, offers a wealth of articles on setting up nginx along with a rails cluster. I followed several other articles in getting FastCGI working through spawn-fcgi with requisite init scripts to ensure everything starts up properly.  Everything was working great until I enabled pretty permalinks and then got the unfortunate error:

No input file specified.

I understood this to mean FastCGI could find the script attempting to be called, but couldn’t immediately see why that was the case.  In the end it was something simple and obvious.

My initial configuration server configuration looked something like:

server {
  listen   80;
...
  location / {
    # this serves static files that exist without running other rewrite tests
    if (-f $request_filename) {
      expires 30d;
      break;
    }

    # this sends all non-existing file or directory requests to index.php
    if (!-e $request_filename) {
      rewrite ^.+?(/.*\.php)$ $1 last;
      rewrite ^ /index.php last;
    }
  }

  location ~ .php$ {
    include /etc/nginx/fastcgi_params;
    fastcgi_pass 127.0.0.1:9000;
    fastcgi_index index.php;

    fastcgi_param SCRIPT_FILENAME /var/www/html/www/public$fastcgi_script_name;

    root /var/www/html/www/public;
  }
}

And searching there were other suggestions for the rewrite as:

    # this sends all non-existing file or directory requests to index.php
    if (!-e $request_filename) {
      rewrite ^(.+)$ /index.php?q=$1 last;
    }

Which made no difference in the error condition. As I said in the end, the problem was something obvious. In my configuration, the wordpress installation is not at the root of the web server, rather it is in a subdirectory called blog. Therefore, with the initial configuration when a path could not be found, rather than call the wordpress index.php script located at /blog/index.php, it was calling just /index.php which initially didn’t exist. Had it existed, I probably would have quickly see which file was getting called and how to address. The change was to set up the wordpress rewrite information in the correct location block. The updated configuration became:

  location /blog {
    # this serves static files that exist without running other rewrite tests
    if (-f $request_filename) {
      expires 30d;
      break;
    }

    # this sends all non-existing file or directory requests to index.php
    if (!-e $request_filename) {
      rewrite ^.+?(/.*\.php)$ $1 last;
      rewrite ^ /blog/index.php last;

    }
  }

I haven’t yet configured out the “No Input file specified” when a bad php url is used, but that will probably be done shortly.

I have been pleased with the cost, performance and service they offer.   Through their great articles, I was quickly able to secure the server and set up and configure the right set of software and services to get things running.

I have started with a 256 slice running Ubuntu and haven’t yet had need to upgrade it to something new.  Initial software configuration includes:

• nginx
• ruby
• php5
• mysql
• git

Since starting with just a server to host a code repository I have moved on to host some additional sites on the server including this blog.  Most of the sites are yet to be publicly available as they are things put together more to learn something than explicitly made available for public consumption.

In the end, this has been a great solution for my needs.