Symptoms
ESXi hostd management daemon crashes on ESXi/vSAN 8.x nodes in on-premises environments and VMC on AWS SDDC versions 1.20v1 till 1.20v4 while using Citrix XenDesktop or other Virtual desktop application services and Aria Automation that deploys Virtual machines with flat VMDK files.
Purpose
This KB is written to inform of this issue and provide both workaround and solution.
Cause
Citrix XenDesktop, or another products deploys flat vmdks files onto the vSAN storage. This results in ESXi 8.x hostd process to crash while trying to read/write to those flat files on the VSAN datastore.
In VSAN's object-based storage, -flat.vmdk and -delta.vmdk files are not directly addressable as datastore paths. Please see KB 50121428 .
Impact / Risks
Having flat file vmdks in your VSAN datastore leads to consumption issues that can result in the disks in your host's storage filling unexpectedly and leading the hosts to crash.
Resolution
To address the hostd crash VMware recommends customers to upgrade to vSphere 8.0U1 in On-premises and in VMC on AWS the issue is fixed in SDDC version 1.20v5 and later.
However, other problems resulting from deploying flat files to the vSAN datastore has remained, such as the Citrix example above. For Citrix environments, there is a fix released and referenced in the Citrix article CTX131239 . Consult with Citrix support on solution interoperability and contact VMware support to confirm upgrade path depending on current configuration state.
Workaround
The hostd instability can be temporarily mitigated by removing all -flat files and restarting hostd.* Note that in certain circumstances hostd may continue to crash while repeatedly attempting to open the flat file indicated by the descriptor file. In this case it may be necessary to comment out the problem vmdk in the vmx descriptor file, and attempt the hostd restart again.Note: If you’re seeing this behavior when using Citrix provisioning services BDM/MCS, please see Citrix CTX131239
