A snapshot called "eam-snapshot" is present in the Snapshot Manager of Agent VM's
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A snapshot called "eam-snapshot" is present in the Snapshot Manager of Agent VM's

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Article ID: 343345

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Updated On:

Products

VMware vSAN VMware NSX for vSphere VMware vCenter Server

Issue/Introduction

Symptoms:

  • You observe a snapshot has been created on an Agent VM (also called "Service VM's" or "Service Nodes") in the vSphere Client: 

 

 

  • This may trigger snapshot alarms, if they are configured for the Agent VM's.

Environment

  • All products leveraging ESX Agent Manager (EAM) to manage the Agent VM deployments.  This includes, but is not limited to:
    • NSX/NSX-T (All versions)
    • vSAN (All Versions)
    • vSphere Cluster Services
    • 3rd Party products

Cause

  • When Agent VM's are deployed, a snapshot of the VM is created that is called "eam-snapshot".  The snapshot is created after VM is provisioned and before it is activated and potentially modified, to ensure it is a "clean snapshot".
  • This snapshot is used so that other deployments of new hosts within the agency scope may make use of  linked clones of the existing Agent VMs to deploy new Agent VM's, as needed, rather than create a full copy, thus decreasing the deployment time and allowing simultaneous deployments within the same scope. The Linked cloning process requires this snapshot.

 

Resolution

  • While it is possible to remove the snapshots without immediate impact, it is not recommended. The intended design is for the snapshot to be left in place.
  • If you are sure that no hosts will be added to the scope of that agency, including hosts being removed and re-added, you could delete the snapshots as a possible troubleshooting step, if needed (as directed by Broadcom Support), rather than as general good practice.  

Additional Information

  • If you remove the snapshot, EAM doesn't consider a VM without a "eam-snapshot" eligible for cloning, thus any new host added to the scope will invoke a full deployment of a VM with downloading OVF, etc., which is the most time-consuming deployment operation.
  • Strictly speaking, cloning of the Agent VM's doesn't need to be done from an existing snapshot. However, a snapshot is implicitly created. If cloning is done without a snapshot, the clone operation on a VM can't be concurrent and it would clone its current state which is undesirable.

  • For more information on EAM, see TechDocs: ESX Agent Manager Definitions
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