Mounting CIFS Shares into VKS Containers Fails

Products

• VMware vSphere Kubernetes Service

Issue/Introduction

• Unable to mount CIFS shares on VKS worker nodes.
• You may receive a generic error message such as:
  

  root [ ~ ]# mount -v -t cifs -o vers=3.0,domain=ent,username=user //##.##.##.##/path /root/mnt/
  mount: /root/mnt: cannot mount //##.##.##.##/path read-only.
         dmesg(1) may have more information after failed mount system call.
  

Environment

VKS Guest Cluster

Cause

• cifs-utils is required to mount the shares properly.
• Guest cluster worker nodes (Tanzu Kubernetes Grid nodes) are based on a minimal Photon OS image that does not include the cifs-utils package by default. 
• To confirm on a guest cluster node, you can run which mount.cifs. If it returns nothing, the package is missing.

 

Resolution

The best way to enable the cifs-utils package for a guest cluster is to build a custom image that includes the package you need. Once you've validated that you have a working configuration, this will prevent the package from being removed during reboots, which will happen if you manually install the package due to the immutable nature of the nodes.