PodPidsLimit Configuration and Recommended Values in VKS

Products

• VMware vSphere Kubernetes Service

Issue/Introduction

This KB explains about the PodPidsLimit Configuration in VKS and recommendations.

Environment

vSphere with Tanzu

Resolution

Kubernetes allows you to limit the number of processes running in a Pod. You specify this limit at the node level and cannot be updated at cluster level. Each Node can have a different PID limit. The PodPidsLimit restriction setting can be configured by adding the "podPidsLimit" parameter to the kubelet configuration file. So, the change will not be persistent across node recreation, as it is applied in the kubelet inside the node, and this will be lost upon node recreation.

By default, the value is set to -1, which is unlimited, and this setting is by design to not keep a limit on the PIDs per pod. While any changes to the PodPidsLimit setting are not tested and supported, we recommend you to keep the value to default as there are technical support limitations for issues that arise from changing this value according to customer policies.
(In case of issues caused by process count limitations, reverting to the original setting will be recommended.)

Additional Information

Current PodPidsLimit for a node can be determined through the command below
"journalctl -u kubelet | grep PodPidsLimit"

 

References - 

Process ID Limits And Reservations | Kubernetes 

Set Kubelet Parameters Via A Configuration File | Kubernetes