ArcGIS Server - Shared Instance Setting Configuration Issue - Service becomes Inaccessible

[SH013]

I'm experiencing an issue where services configured on shared instances have now become inaccessible. It seems as though the ArcGIS Web Adaptor cannot access the required property to recognize that the service is configured as a Shared Instance, leading it to believe that the server machines are unavailable. Although reconfiguring the service with the dedicated instance setting makes the REST URL accessible again, it is at a cost of using more server resources temporarily. I would like to find out if there is a permanent solution to fix the shared instance since they're no longer working anymore. It's more likely that I will submit a support ticket, but I wanted to see if anyone has encountered this before. I should mention here that we're running ArcGIS Enterprise 10.9.1 and our config and directory stores reside in a dedicated file server that resides separately from the ArcGIS Server machines. It's a multi-machine ArcGIS Server site. Thanks!

[TonyContreras_Frisco_TX]

Have you check the logs and service statistics in the Server Manager? Do you see anything that might describe the issue and/or a cause? If you have the resources available on the servers, it might help to increase the number of instances in the shared instance pool for the site.

[SH013 · Accepted solution]

Hello, the log does not indicate any issues, but I was able to figure it out at the end. This took me a while to figure out since there wasn't a lot of documentation that definitively explains this, but the shared instances are powered by the DynamicMappingHost Service in the System tool, which had malfunctioned and needed to be repaired/replaced.

[CamposEPC]

How did you repair the DynamicMappingHost Service exactly? I've stopped and started in the admin tools, but the problem just persists.

Thanks

[SH013 · Accepted solution]

sorry late reply here, but not sure if my solution is applicable but I essentially I had to replace the entire JSON file tied to the DynamicMappingHost as it was accidentally altered 

[MicahSeybold]

We are also having the same issue and would like to know how to repair the DynamicMappingHost Service.

[MicahSeybold]

This issue happened to our ArcGIS Enterprise deployment version 11.3.   The solution that Esri Support suggested was to simply restart the Portal and ArcGIS Server services.   

• Restart ArcGIS Server Machine first.
• Once the machine is restarted,
• restart the Windows Services in Portal for ArcGIS.
• Wait for about 10 minutes and make sure that the Portal for ArcGIS is up and running.
• If confirmed, then Restart the Windows Services for ArcGIS Server.

These steps solved our problem.