MathJax CDN migration

Problem

MathJax announced it would shut down its custom CDN on April 30, 2017: https://www.mathjax.org/cdn-shutting-down/ . If your Open edX instance is trying to load MathJax from cdn.mathjax.org, you will see failures in the browser for problems that use MathJax.

The exact text of the failures depend on the browser. Possibilities include:

  • Unable to load Problem: Cannot read property ... 'Queue' of undefined
  • Unable to load Problem: undefined is not an object (evaluating 'MathJax.Hub.Queue')

Solution

We updated master and Ficus with a replacement CDN, changing 

//cdn.mathjax.org/mathjax/2.7-latest/MathJax.js

to 

//cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js

This change was made in Ficus.3.  If you are running Ficus, be sure you are running at least Ficus.3.

If you are not running Ficus, you can make a similar change to your running instance.

Other resources

The openedx-ops discussion: https://groups.google.com/forum/#!topic/openedx-ops/ORtypVmdWwQ/discussion

The fix we made on master and Ficus: https://github.com/edx/edx-platform/commit/f90b80da6299347868ba3a53598e4e7836d0a27c