"No coredump target has been configured" alert triggered on ESXi hosts following upgrade

Products

• VMware vSphere ESXi

Issue/Introduction

• Following a major version upgrade of an ESXi host, a vCenter Server alarm is asserted: "No coredump target has been configured. Host core dumps cannot be saved."
• Execution of esxcli system coredump file list reveals an existing .dumpfile on a datastore, but the output indicates that both Active and Configured boolean values are false.
  Example Output:
  

  Path                                                                                                     Active  Configured        Size
  -------------------------------------------------------------------------------------------------------  ------  ----------  ----------
  /vmfs/volumes/<Datastore_UUID>/vmkdump/<Filename>.dumpfile                                                false       false  ##########

Environment

VMware vSphere ESXi

Cause

ESXi architectures automatically generate a file-based coredump within the consolidated ESX-OSData volume. During a hypervisor upgrade, the process is designed to inherit this layout. However, architectural changes to the OSData internal structure, transient storage topology initialization delays during the post-upgrade boot sequence, or underlying datastore UUID alterations can sever the runtime link to the existing dump file. Consequently, the .dumpfile physically persists on the storage volume, but the kernel drops the active configuration pointer, rendering it inactive.

Resolution

The diagnostic coredump file must be re-registered as the active target within the ESXi kernel.

1. Establish an SSH or physical console session to the affected ESXi host using root credentials.
2. Instruct the VMkernel to intelligently select and activate the existing coredump file by executing the following command:
   esxcli system coredump file set --smart --enable true
Or utilize the output from the file list command to declare the exact file path:
   esxcli system coredump file set -p /vmfs/volumes/<Datastore_UUID>/vmkdump/<Filename>.dumpfile --enable true
   

   Note: For more information on configuring the coredump file, see Configuring ESXi coredump to file instead of partition

3. Validate the runtime configuration state:
   esxcli system coredump file list
4. Confirm that the specific file path now reflects true under both the Configured and Active columns.

The vCenter Server host health alarm will automatically clear upon the next polling cycle once the active diagnostic target is detected.