vAPI and SOAP Session maxSessionCount: Modification in vCenter Server 8.0 U3

Products

• VMware vCenter Server
• VMware vCenter Server 8.0

Issue/Introduction

Starting with VMware vCenter Server 8.0 U3, a single vAPI session allows the execution of both SOAP and REST APIs. With these architectural changes, session management is consolidated entirely within vpxd. The maxSessionCount limit is now enforced centrally rather than independently.

Environment

VMware vCenter Server 8.0 U3 and later

Cause

• In releases earlier than VMware vCenter Server 8.0 U3, connection and session limits are enforced independently by the vapi-endpoint.

• The number of sessions per user in earlier releases is defined by the maxSessionsPerUser parameter in the /etc/vmware-vapi/endpoint.properties configuration file.

• Starting with VMware vCenter Server 8.0 U3, the vSphere Management API (VIM) and vSphere Automation API (vAPI session) are combined.

• Authentication is effectively unified across SOAP and REST vCenter Server endpoints.

• Consequently, the session limit is now governed by the maxSessionCount setting within vpxd.

Resolution

The session limit is configured through the common vpxd property config.vmacore.soap.maxSessionCount in the /etc/vmware-vpx/vpxd.cfg file. The configuration is also available through the vSphere Client UI.

The default maximum number of in-flight sessions is common for both SOAP and vAPI sessions, with a default value of 3000.

Modification via the vpxd.cfg file

1. Take a backup of the vpxd.cfg file from /etc/vmware-vpx/

2. Stop the vpxd service with the following command:

   service-control --stop vmware-vpxd
   

3. Add the soap and maxSessionCount entries as shown below:

   <config>
   ...
     <vmacore>
     ...
       <soap>
       ...
         <maxSessionCount>6000</maxSessionCount>
       ...
       </soap>
     ...
     </vmacore>
   ...
   </config>
   

4. Start the vpxd service with the following command:

   service-control --start vmware-vpxd

Modification via the vSphere Client

Add the advanced setting to VMware vCenter Server by following these steps:

1. Navigate to Configure -> Settings -> Advanced Settings.

2. Add the following setting:

   • Name: config.vmacore.soap.maxSessionCount

   • Value: 6000

Additional Information

• Refer to the following article when troubleshooting Aria Automation data collection failures caused by reaching the maximum user session count limit:

  • vCenter cloud account datacollection fails in Aria Automation with "The connection with vAPI endpoint can not be established failedToLoginMaxUserSessionCountReached"

• Refer to below documentation when attempting to understand the unified Management and Automation API session architecture and usage in vSphere 8.0:

  • An Introduction and Getting Started with vSphere APIs and SDKs 8.0

• Refer to below blog post when assessing endpoint limits and investigating performance impacts related to concurrent REST requests in vCenter Server:

  • Endpoint Limits for Concurrent REST Requests from vCenter APIs