vSphere HA State Shows "HA Agent Unreachable" Across Secondary Hosts Due to Fault Domain Manager (FDM) VIB Build Mismatch
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vSphere HA State Shows "HA Agent Unreachable" Across Secondary Hosts Due to Fault Domain Manager (FDM) VIB Build Mismatch

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Article ID: 452040

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Updated On:

Products

VMware vCenter Server

Issue/Introduction

In a vSphere HA cluster, the Primary (Master) host reports a normal status in the vSphere Client, while all Secondary (Slave) hosts display the following warning:

  • vSphere HA State: HA Agent Unreachable

  • Warning icons are present on the secondary ESXi hosts in the inventory tree.

/var/log/fdm.log across the cluster hosts reveals the following errors:
From master Host:
Wa(164) Fdm[####]: [Originator@6876 sub=Election opID=clusterElection.cpp:1570-e73a23e] [60 times] Build mismatch (24853646 != 25600417) from host ##.##.##.## - dropping message

From slave Hosts:
Wa(164) Fdm[####]: [Originator@6876 sub=Election opID=clusterElection.cpp:1570-640a74aa] [60 times] Build mismatch (25600417 != 24853646) from host ##.##.##.## - dropping message

SSL Handshake and Peer Binding Failures (Port 8182):
Wa(164) Fdm[####]: [Originator@6876 sub=IO.Connection opID=WorkQueue-####] Failed to SSL handshake; SSL(..., <TCP '##.##.##.## : 8182'>, <TCP '##.##.##.## : 35432'>), e: 167772427(wrong version number (SSL routines)), duration: 0msec
Er(163) Fdm[####]: [Originator@6876 sub=Message opID=WorkQueue-####] Error N7Vmacore3Ssl12SSLExceptionE(SSL Exception: error:0A00010B:SSL routines::wrong version number)
Er(163) Fdm[####]: [Originator@6876 sub=Message opID=WorkQueue-####] No peer binding info on ssl connection - dropping the connection

Environment

VMware ESXi 8.0 
VMware vCenter 8.0 

Cause

This issue occurs when the vmware-fdm VIB versions are desynchronized across hosts in the same HA cluster.

Resolution

To resolve this issue, you must synchronize the vmware-fdm VIB version across all hosts in the cluster. Toggling vSphere HA at the cluster level forces vCenter to push and install the latest matching FDM Agent VIB simultaneously across all nodes.

  1. Log in to the vSphere Client.

  2. Navigate to the affected Cluster object .

  3. Select the Configure tab > vSphere Availability.

  4. Click Edit.

  5. Uncheck "vSphere HA" and click OK to disable HA across the cluster.

  6. Wait 2 to 3 minutes to allow vCenter to cleanly stop and uninstall the FDM agents from all hosts.

  7. Click Edit, re-check "vSphere HA", and click OK.

  8. vCenter will automatically push and install the uniform 8.0.3-25600417 FDM VIB package to all ESXi hosts in the cluster and complete the HA Master election.


Verification:

  1. Navigate to Cluster > Monitor > vSphere Availability > Summary. Verify that the cluster shows 1 Primary Host and 5 Connected Secondary Hosts.

  2. Select each ESXi host > Configure > System > Packages. Search for vmware-fdm and verify that the version on all hosts displays 8.0.3-25600417.

  3. Check Host > Summary > Configuration > vSphere HA State. Confirm that the status displays Connected (Master) or Connected (Secondary) with a green checkmark.

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