Addressing "Admission failure in path" messages regarding nsx-datapath-ctrs in ESXi

Products

• VMware vSphere ESXi
• VMware NSX

Issue/Introduction

• "Admission failure in path:" warnings related to nsx-datapath-ctrs are observed in the vmkernel.log of an ESXi host.
• When investigating ESXi host performance issues, memory exhaustion, or unexpected reboots, you may encounter log snippets similar to the following in /var/log/vmkernel.log:

2026-07-04T18:09:32.562Z In(182) vmkernel: cpu14:2409756)python3.2409756 (2670002) requires 1172 KB, asked 1172 KB from nsx-datapath-ctrs (18041) which has 266240 KB occupied and 0 KB available.
2026-07-04T18:09:32.562Z Wa(180) vmkwarning: cpu14:2409756)WARNING: UserParam: 1548: python3: could not change group to <host/vim/vmvisor/nsx-datapath-ctrs>: Admission check failed for memory resource

Note: It is critical to differentiate between resource pool admission failures and host-wide memory exhaustion. This specific error is isolated to the NSX datapath counters resource pool.

Environment

VMware vSphere ESXi

VMware NSX

Cause

An admission failure indicates that ESXi is failing to allocate a requested amount of memory for a specific process because that process has reached its configured resource limit.

In this scenario, the nsx-datapath-ctrs resource group has a hardcoded memory ceiling of approximately 260 MB. When a process (such as python3 in the log example) requests additional memory that would push the group beyond this 260 MB limit, ESXi’s resource management actively denies the request. This results in the logged admission check failure.

Resolution

• No action is required to resolve host-level memory exhaustion based on this error.
• These admission failure errors related to nsx-datapath-ctrs do not cause reboots or memory exhaustion on the ESXi host.
• Because nsx-datapath-ctrs is strictly capped at ~260 MB, it is physically impossible for this process to consume enough memory to starve an ESXi host (which typically operates with tens or hundreds of gigabytes of RAM).
• In the context of investigating an ESXi host that has become unresponsive, crashed, or unexpectedly rebooted, admission check failures related to nsx-datapath-ctrs can be safely ignored.
• If further investigation is required to determine exactly why the nsx-datapath-ctrs process is running out of its allocated memory, please open a Support Request with the Broadcom VMware NSX support team. Creating and managing Broadcom cases

Additional Information

• To validate the memory utilization and limits for the nsx-datapath-ctrs group in real-time, you can execute the following command in a live SSH session on the affected ESXi host:

memstats -r group-stats -l2 -s name:min:max:conResv:availResv:eMin:eMinPeak:consumed:consumedPeak -g 21

This command will output the current memory statistics, confirming the maximum limit and current consumption for the specified resource group.

• Reference article: Addressing "Admission failure in path:" messages in ESXi