KB-1235 Issues with multiple gateways in Appian 16.2

Symptoms

In a dual gateway scenario in Appian 16.2, users may experience one or more of the following symptoms.

Symptom 1

Users are unable to upload a file using the File Upload field. The following error is returned:

Error Evaluating UI Expression

Expression evaluation error in rule 'XXX' (called by rule 'YYY') at function a!fileUploadField [line ZZZ]: Error evaluating function fn!content_appian_internal : Invalid Content ID

The following log lines are printed in the application server log as a result:

INFO  [stdout] (http-/0.0.0.0:8080-6) 2016-08-12 15:38:10,315 [http-/0.0.0.0:8080-6] ERROR com.appiancorp.rest.shared.AppianExceptionMapper - Internal Server Error on REST API invocation.
INFO  [stdout] (http-/0.0.0.0:8080-6) com.appiancorp.process.expression.ExpressionRuntimeException$AppianExceptionProvider: Expression evaluation error in rule 'XXX' at function a!fileUploadField [line 10]: Error evaluating function fn!content_appian_internal : Invalid Content ID (APNX-1-4198-000)
...
INFO  [stdout] (http-/0.0.0.0:8080-6) Caused by: com.appiancorp.suiteapi.content.exceptions.InvalidContentException: Invalid Content ID
...

Symptom 2

If the "Generate XML Document" node is used in a process model, that node will fail. The following log lines are printed in the application server log as a result:

INFO  [stdout] (Appian Work Item - 1 - ProcessExec02 : UnattendedJavaActivityRequest) 2016-08-12 15:42:37,498 [Appian Work Item - 1 - ProcessExec02 : UnattendedJavaActivityRequest] ERROR com.appiancorp.process.engine.UnattendedJavaActivityRequest - An error occurred while executing activity: id=XXX, classname=com.appiancorp.process.runtime.activities.CreateDocumentFromTemplateActivity601
INFO  [stdout] (Appian Work Item - 1 - ProcessExec02 : UnattendedJavaActivityRequest) com.appiancorp.suiteapi.process.framework.ActivityExecutionException: Unable to write output document
...
INFO  [stdout] (Appian Work Item - 1 - ProcessExec02 : UnattendedJavaActivityRequest) Caused by: com.appiancorp.kougar.driver.exceptions.Signal: E106
...

Symptom 3

A user may publish an application with or without any application actions configured. If a user publishes an application, then adds an application action after it's published, the application action will not always display in Tempo. Refreshing the page will show it intermittently disappear and reappear.

Users will also notice that after experiencing this behavior, if they unpublish and republish the application, the application action disappears.

Additionally, when creating new objects or adding existing objects to an existing application, various pink box errors are returned.

Cause

This issue has been addressed via AN-73571 in the following hotfixes/versions:

• Appian 16.2 Hotfix Package D
• Appian 16.3

Action

Apply the latest hotfix to your Appian installation or upgrade to the latest version of Appian.

Appian Technical Support strongly encourages our customers on a dual gateway setup and running Appian 16.2 to either apply the latest 16.2 hotfix or to upgrade to 16.3.

Workaround

Disable the second gateway and restart the environment.

Affected Versions

This article applies to Appian 16.2.