title: Allow WordPress write access to Docker mounted folder
body: <p>I have a Docker setup that works well with Ubuntu, Nginx, PHP-FPM and MySQL. </p>
  
  <p>WordPress can write to the uploads folder and I can edit templates online, but when I try to upgrade WordPress or plugins, it fails with:</p>
  
  <blockquote>
    <p>Unpacking the update…</p>
    
    <p>Could not create directory.: wordpress</p>
    
    <p>Installation Failed</p>
  </blockquote>
  
  <p>I have <code>chmod 777</code> the entire WordPress folder, so I'm not sure if this is Docker or WordPress related. I have also checked various logs, but the only relevant line I found is this:</p>
  
  <blockquote>
    <p>192.168.59.3 - - [01/Oct/2014:14:16:58 +0000] "POST /wp-admin/update-core.php?action=do-core-upgrade HTTP/1.1" 200 5576
    "/wp-admin/update-core.php" "Mozilla/5.0
    (Macintosh; Intel Mac OS X 10_10_0) AppleWebKit/537.36 (KHTML, like
    Gecko) Chrome/37.0.2062.124 Safari/537.36"</p>
  </blockquote>
  
  <p>Here's how I created the Docker environment:</p>
  
  <pre class="lang-sh prettyprint-override"><code>brew install docker boot2docker
  boot2docker init
  # Allow VM access to our space
  curl http://static.dockerfiles.io/boot2docker-v1.2.0-virtualbox-guest-additions-v4.3.14.iso &gt; ~/.boot2docker/boot2docker.iso
  VBoxManage sharedfolder add boot2docker-vm -name home -hostpath /Users
  boot2docker up
  </code></pre>
  
  <p>Here's how I start the container:</p>
  
  <pre class="lang-sh prettyprint-override"><code>docker run -p 80:80 --name wp -d -v ~/wordpress:/mnt/www:rw wp
  </code></pre>
  
  <p>Here's the Nginx configuration:</p>
  
  <pre><code>server {
  
      listen   80; ## listen for ipv4; this line is default and implied
      listen   [::]:80 default ipv6only=on; ## listen for ipv6
  
      root /mnt/www;
      index index.php index.html index.htm;
  
      # Make site accessible from http://localhost/
      server_name localhost;
  
      location / {
          # First attempt to serve request as file, then
          # as directory, then fall back to index.html
          try_files $uri $uri/ /index.php?q=$uri&amp;$args;
      }
  
      #error_page 404 /404.html;
  
      # redirect server error pages to the static page /50x.html
      #
      error_page 500 502 503 504 /50x.html;
      location = /50x.html {
          root /usr/share/nginx/www;
      }
  
      # pass the PHP scripts to FastCGI server
      #
      location ~ \.php$ {
      try_files $uri =404;
          fastcgi_split_path_info ^(.+\.php)(/.+)$;
          # NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini
  
          fastcgi_pass unix:/var/run/php5-fpm.sock;
          fastcgi_index index.php;
          include fastcgi_params;
      }
  
  }
  </code></pre>