Citrix, Shadow Copy, Certificates and frozen sessions

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ThomasTIP
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Citrix, Shadow Copy, Certificates and frozen sessions

Post by ThomasTIP »

Hi,

Coinciding with including your OPC libraries in our application, there are random Citrix issues for those users accessing OPC functionality. Their Citrix session gets stuck and cannot be disconnected anymore - so far, the Citrix admins could only solve the problem by completely restarting the Citrix server. This occurs every 2 or 3 days.
We are currently trying to isolate these users on a separate Citrix server to find out more about this problem.
The only lead I currently have, which I have to investigate in order to prove that the new libraries are not the cause, is the issue described below:

Our application uses shadow copy. I have copied the Opc.Ua.CertificateGenerator.exe to the main directory, where my application EXE and the required DLLs are located. When a Citrix user runs the application, the EXE and the DLLs are copied to a local path, but when OPC is initialized, I receive the following error:

05:26.41|0001|01|4|Processing Command Line: {\\server\myapp\myapp.exe}
05:26.41|0001|01|1|[Bad] Unexpected error raising MissingApplicationCertificate event.|ArgumentException|MissingApplicationCertificate: Error creating certificate: Cannot find the CertificateGenerator utility in C:\Users\mycitrixuser\AppData\Local\assembly\dl3\CM496VAZ.RPW\N94QNK36.WZN\adfe3a00\0050ba65_725ed601. Please check your configuration.
05:26.41|0001|01|4|Certificate NOT created by MissingApplicationCertificate EventHandler
05:26.41|0001|01|4|Creating Certificate in Store: \\server\myapp\OpcClientCertificate
05:26.41|0001|01|1|[BadConfigurationError] Could not create a new certificate.|StatusException|Cannot find the CertificateGenerator utility in C:\Users\mycitrixuser\AppData\Local\assembly\dl3\CM496VAZ.RPW\N94QNK36.WZN\adfe3a00\0050ba65_725ed601. Please check your configuration.

However, the application then continues to connect successfully and everything seems to work fine.
The shadow copy subfolder referred to in the log is the one that contains the Unified.Automation.UaBase.DLL - it is unclear to me why it would use this folder to search for the ClientGenerator Exe, and why it can still continue if a valid certificate was not created. Could you perhaps shed some light on this?

Regards
Thomas

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Re: Citrix, Shadow Copy, Certificates and frozen sessions

Post by Support Team »

Hello,

The location of the UaBase.dll is the default path for Opc.Ua.CertificateGenerator.exe. If this tool cannot be found, you can configure its location code by setting the property CertificateFactory.CertificateGeneratorPath (http://documentation.unified-automation.com/uasdkdotnet/3.0.5/html/classUnifiedAutomation_1_1UaBase_1_1CertificateFactory.html#ad99e2cc7c07617c5a9bfd1e0c597b5c9).

If the ApplicationInstanceCertificate cannot be created, you can use OPC UA communication without security.
Best regards
Unified Automation Support Team

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