Addressing "Admission failure in path:" messages in ESXi

Products

• VMware vSphere ESXi

Issue/Introduction

"Admission failure in path:" messages spewing in vmkernel.log of an ESXi host. For example "2026-01-13T19:02:26.719Z hostname.domain.com vmkernel: cpu24:5781314)Admission failure in path: host/vim/vmvisor/dcui:dcui.2105653:uw.2105653".

Depending on the impacted service (DCUI service in the above example) the host may become slow or unresponsive.

NOTE: This error can be seen on occasion on any given environment, it should only be treated as a problem if it is seen constantly in the logs.

Cause

An admission failure indicates that ESXi is failing to allocate the requested amount of memory for a given process. In the example "2026-01-13T19:02:26.719Z hostname.domain.com vmkernel: cpu24:5781314)Admission failure in path: host/vim/vmvisor/dcui:dcui.2105653:uw.2105653" this process would be the DCUI process. Common causes are memory leaks or leaving a task running indefinitely (for example leaving a remote console to the DCUI connected and refreshing constantly).

Resolution

• Identify and restart the service in question via a management agent restart.
  • Restarting Management Agents in ESXi
  • Warning:
    • Do not use the services.sh restart command on ESXi hosts running vSAN
    • Do not use the services.sh restart command if LACP is in use
    • Do not use the services.sh restart command if NSX is configured in the environment
    • Do not use the services.sh restart command if using shared graphics in a View environment (VGPU, vDGA, vSGA)

    Restarting the host management agents may impact currently running tasks, including impacting performance on the guest virtual machines of that host.

• If still seeing the error after restarting the service, put the host into maintenance mode, migrate any running VMs off, and reboot the host. This will clear any cached memory and terminate any indefinitely running tasks.
  • Place a Host in Maintenance Mode
• If still seeing the issue after a host reboot, please open a case with Broadcom to investigate. Note that an ESXi log bundle may be needed.
  • Creating and managing Broadcom support request (SR) cases
  • Collecting diagnostic information for ESXi hosts and vCenter Server using the vSphere Client

Additional Information

There are various known issues for admission failures for various services across various builds of ESXi, many of them benign, so it is also advised to search the Knowledge Base for your specific error. Some examples are listed below, however this list is not comprehensive.

vmkernel logs reporting Admission failure in path: host/user/pool0/pool1/vm####:vmmanon.#####

Host Remediaton fails intermittently when upgrading ESXi version with single image managed cluster

vSAN traces daemon (vsantraced service) fails with admission failure errors