Install the zmq PHP extension v1.1.2 using PECL.
Install PHP v5.5.6.
Ensure Chef can download remote files.

Work around a Chef -bug- behaviour where the cache directory isn't
created before Chef Solo runs.
Use v.2.4.2 of the yum cookbook.

https://github.com/opscode-cookbooks/yum/commit/f9e182ee68b7935e5a3de72f1abd078c0d747545#diff-ea218fc13ddbe174ac160d2f69f9a01b
causes a SyntaxError exception to be thrown by Ruby v2.0.0p353.