Amazon MR is great for analyzing web server logs. In some cases that requires deciphering user agent string which can be a daunting task. There are mulitple agent strings for any browser family, version and plugins enabled.

One of the tools which helps with maching agent is http://us2.php.net/manual/en/function.get-browser.php . To get it working it requires external browscap.ini file and php.ini update. It is possible to achieve this with updating php.ini in MR bootstrap action http://www.zlender.net/2011/02/25/amazon-elastic-map-reduce-adding-php-e...

I've ran into an issue with my PHP mapper script where an PHP extension I needed was missing. These are the extensions available that mapreduce instances start with by default.

hadoop@ip:~$ php -m
[PHP Modules]
bcmath
bz2
calendar
ctype
date
dba
dom
exif
filter
ftp
gd
gettext
hash
iconv
imagick
json
libxml
mbstring
mime_magic
ncurses
openssl
pcntl
pcre
PDO
pdo_sqlite
posix
Reflection
session