Upgrading a rather large Communications Manager cluster I needed to upgrade all of the subscriber nodes at the same time.

The general rule still applies when upgrading a Cisco CM cluster – Publisher upgrades first and do not switch to upgraded partition.

Now there is a certain point during the publisher upgrade that I can actually start upgrading on all the subscribers in parallel. Be sure you have the proper compute and MHz reservation because you don’t want to overload all subscribers at once.

1. SSH to your Publisher or get on the console
2. List the install logs
   1. admin:file list install install_* date
      
   2. install_log_2014-04-06.20.39.48.log
   3. dir count = 0, file count = 1
3. Search the most recent install log for “PRODUCT_VERSION”
   1. file search install install_log_2014-04-06.20.39.48.log PRODUCT_VERSION
      
      1. 04/06/2014 20:52:30 post_upgrade|PRODUCT_VERSION is 9.1.2.11900-12|<LVL::Info>
      2. 04/06/2014 20:52:30 post_upgrade|PRODUCT_VERSION_DISPLAY is 9.1.2.11900-12|<LVL::Info>
      3. Search completed
4. When the file search command finds the PRODUCT_VERSION string in the install log, you can start the upgrade of the subsequent nodes.
   1. If you want to upgrade the subsequent nodes in parallel with the publisher node, do not choose the Reboot to upgraded partition on either publisher node or subsequent nodes while configuring the upgrade options. If selected, the publisher node may complete its upgrade and reboot while the subsequent nodes are upgrading, which causes the upgrade of the subsequent nodes to fail.

When you are ready to activate the new version, you must activate the new software on the publisher node before activating it on all other nodes.