Automic Workload Automation

This evening, we upgraded one of the two nodes of one of our AE servers from v11.2.1 to 12.0.2, using the new zero downtime upgrade capability introduced in v11.2. We are still running in compatibility mode, meaning that although the first node has been upgraded, the second node is still running the old version of the AE server.

After the upgraded v12 WPs and CPs came up, we noticed something unexpected: none of the WPs — on either node — started up as dialog work processes (DWPs). We have configured WP_MIN_NUMBER in UC_SYSTEM_SETTINGS so that a portion of work processes are dedicated to be normal work processes; the remainder though should be available to switch to dialog work processes, and normally all of the WPs not dedicated to be normal WPs switch to become DWPs. We saw no DWPs at all.

When we tried to switch one of them to DWP mode manually, we learned the reason:

Error: U00011898 Switch server mode to DWP not allowed during Zero Downtime Upgrade.

This limitation is not mentioned anywhere in the ZDU documentation. It probably should be.

Another ZDU gotcha;

I upgraded our dev V11.2.1 to V11.2.4 on Windows and deliberately left it in compatibility mode over a weekend.  I came in on Monday after the server had been rebooted for security patching.  The act of rebooting the server FINALIZED the upgrade.

Pete Wirfs wrote:

Another ZDU gotcha;

I upgraded our dev V11.2.1 to V11.2.4 on Windows and deliberately left it in compatibility mode over a weekend.  I came in on Monday after the server had been rebooted for security patching.  The act of rebooting the server FINALIZED the upgrade.

Yes, petwir, my colleague Umberto_Bilato_262 discovered this detail during testing of ZDU in our experimental system. He was startled to find that once the last WP/CP running the old version had stopped, this finalized the upgrade and made it impossible to reconnect to the DB using the old versions of the WP/CP programs. This limitation is not clearly documented, and it greatly limits the usefulness of compatibility mode.

As long as the PWP is still running on the old MQ set there's no switch from WP to DWP possible.

Michael A. Lowry

I will create a ticket to have this information added to our documentation.

Thanks, Alexander_Trenker_120. Would you also please document the other limitation — that compatibility mode automatically ends as soon as the last WP running the old version ends? Thanks in advance.

I had Automic consultants on site for the upgrade of 11.2.1 to 11.2.4 and they struggled to finalize the upgrade.  I'm trying to do this now on my test system for 11.2.4. to 11.2.5 and I've restarted every agent, kicked out all the users and stopped and started all the CP's and WP's for the 11.2.4.  I think I might restart the server over the weekend to finalize it!

PRB00137866 was opened to add those two facts to the Automic documentation 11.2, 12.0 and 12.1.

The documentation has been updated. The v12.1 ZDU Upgrade Process page includes these two notes:

While you are in compatibility mode, you are not allowed to switch a WP to a DWP.

...

When an Automation Engine process running the old version stops, it cannot be restarted. When all Automation Engine processes running the old version have stopped (e.g. because of a power failure), the ZDU finalizes the upgrade process. No rollback is  possible in this case.