When setting up Content Hub to export the content with Drush, you need to set up a cron job that handles that task for you.

The best thing to do is to SSH to the instance and practice running the Drush command a few times with all of the flags set to make sure that you are getting the result you want before adding it to your Scheduled Jobs as a task to be triggered with cron. 

It helps to get the name of the queue that you need to run.  The simplest way to do this is with 

drush9 queue:list

You should get a list of queues and the number of items: 

------------------------------------------ ------- ---------------------------------
  Queue                                      Items   Class
 ------------------------------------------ ------- ---------------------------------
  acquia_contenthub_export_queue             646     Drupal\Core\Queue\DatabaseQueue
  acquia_contenthub_import_queue             0       Drupal\Core\Queue\DatabaseQueue
  locale_translation                         0       Drupal\Core\Queue\DatabaseQueue
  media_entity_thumbnail                     0       Drupal\Core\Queue\DatabaseQueue
  seasonal_sort_queue                        0       Drupal\Core\Queue\DatabaseQueue
 ------------------------------------------ ------- ---------------------------------

To export content to Content Hub use the drush queue-run command, and the name of your export queue, in this case that's acquia_contenthub_export_queue. The -v gives you verbose loggging, and -l runs the queue for the publisher site. Be sure to use the https:// and the fully qualified domain name for the publishing site as this command sets all paths that are used for images, and some other types of content. 

drush -v -l [https://publisher-site.com|https://publisher-site.com/] -root=/var/www/html/<account>.<env>/docroot queue-run acquia_contenthub_export_queue

If you'd like to add logging to this command to pipe that output to a log file use, append a logging string: 

drush -v -l [https://publisher-site.com|https://publisher-site.com/] -root=/var/www/html/<account>.<env>/docroot queue-run acquia_contenthub_export_queue       &>> /var/log/sites/${AH_SITE_NAME}/logs/$(hostname -s)/ach-ex0-`date +%F`.log

There may be times that you want to use flock on cron to prevent cronjobs from overlapping this is what this command does: 

flock -xn /tmp/ach-exp0.lck -c "drush -v -l [https://publisher-site.com|https://publisher-site.com/] -root=/var/www/html/<account>.<env>/docroot queue-run acquia_contenthub_publish_export" &>> /var/log/sites/${AH_SITE_NAME}/logs/$(hostname -s)/ach-ex0-`date +%F`.log

Note

If you are just using Personalization, you don't have to set up a job to import content from Content Hub. Personalization imports that directly from the "Hub" of content.  There is no need to have the content on the Drupal site that you are personalizing (also in many cases it s the same site but it doesn't have to be). 

If you are using Content Hub Syndication, and you need to set up an scheduled job to import content in a scheduled (cron) job, this is the format of that command: 

It includes flock, and setting verbose logging, and setting the path for the import site. 

flock -xn /tmp/ach-imp1.lck -c "drush -v -l [https://subscriber-site.com|https://subscriber-site.com/] -root=/var/www/html/<account>.<env>/docroot queue-run acquia_contenthub_import_queue " &>> /var/log/sites/${AH_SITE_NAME}/logs/$(hostname -s)/ach-i1-`date +%F`.log

Double-check Acquia Purge settings.

Most sites use Acquia Purge, and it's helpful to also double-check that your cron job for Acquia Purge is running after the Content Hub import has completed. That will allow the Purge queue a chance to run, which will automatically update imported and saved items.

drush9  p:queue-work --finish

Using the --finish flag allows the Purge module to safely purge items in batches until the queue is completely emptied.

Please reach out in a Support ticket if you have additional questions.