/var/log/httpd/access_log is not being written on the web servers in an NG cluster.
On the web servers included into NG cluster the module
h2e_logs_module is used, in order to provide an ability to write individual
access_log files in their webspaces.
This module currently does not support having common access log on the server. There is existing request #PFR-1881 to implement this functionality in the module.
Please contact your TAM in order to clarify the status of the feature request.