KB170990355: WebCenter - How stable is the link between Automation Engine and WebCenter when one of the Servers is down

Question

• How stable is the link between Automation Engine and WebCenter when one of the severs is down? To what extent does the system recover when one of the Servers was temporarily down?
• What happens when WebCenter tries to connect with Automation Engine, but Automation Engine is not running?
• What happens when Automation Engine tries to connect with WebCenter, but WebCenter is not running?

Answer

We consider following scenarios:

1. WebCenter is down at the moment a Workflow Task on Automation Engine finishes.

2. WebCenter is down when Automation Engine launches a call which interacts with WebCenter.

3. Automation Engine is not running at the moment the Submit To Workflow Task is executed.
   

4. Automation Engine is down when WebCenter finishes an Approval Cycle started from Automation Engine.   
5. Automation Engine is down when WebCenter synchronizes with Automation Engine.

1. WebCenter down: Workflow Task on Automation Engine finished

WebCenter can start Workflow Tasks in Automation Engine using the Submit Workflow node in the Workflow editor. When a Workflow Task finishes, Automation Engine sends information about the Task Status back to WebCenter. If WebCenter is down at that moment, the information cannot be sent to WebCenter. Fortunately, Automation Engine detects when WebCenter is available again, so any messages from Automation Engine to WebCenter are delivered once WebCenter is started again. 

2. WebCenter down: Automation Engine tries to interact with WebCenter 

If WebCenter is down at the moment an Automation Engine ticket is launched which interacts with WebCenter, the task ends immediately with an error. It is possible to relaunch the task when WebCenter is up and running again. This applies to all tickets that interact with WebCenter:

1. Integrate with WebCenter
2. Publish on WebCenter
3. Create or Modify WebCenter Project
4. Download WebCenter Document
5. Publish Imposition on WebCenter

3. Automation Engine down: 'Submit To Workflow' Task executed

When trying to start a Workflow in Automation Engine from a Webcenter Task, using the Submit Workflow node, the Workflow Task on WebCenter will immediately result in an error in case Automation Engine is not running. In the WebCenter Workflow, the following error message is displayed:

"Ticket not found in Automation Engine".

After the Automation Engine server is up and running again, the task can be restarted by opening the Workflow, right-clicking and the error message and clicking Retry. The Workflow Task will retry and if Automation Engine is running, the Task will continue.

4. Automation Engine down: WebCenter finishes Approval Cycle started from Automation Engine

If Automation Engine is down at the moment a WebCenter Approval Cycle (started from Automation Engine) finishes, the message cannot be delivered to Automation Engine. These messages are stored in WebCenter and when Automation Engine is up and running again, the message is delivered. 

5. Automation Engine down: WebCenter tries to sync with Automation Engine

If WebCenter tries to synchronize with Automation Engine (using a Workflow Connection or Sync Workflow node) while Automation Engine is down, the synchronization gets lost in case the connection type is a JMF workflow connection. There is no way to recover the lost synchronization message. In case the connection type goes over hotfolders, the synchronization message is picked up when Automation Engine is started again.

Read the following article for more details on the difference between JDF and JMF Workflow Connections:

• Page:
  KB169411802: WebCenter - What is the difference between JDF and JMF for Workflow Connection