nconnect mount option does not work with aznfs mount in Azure linux distro

[andyzhangx]

What happened:

nconnect mount option does not work with aznfs mount in Azure linux distro

Customer recently migrated AKS connection to blob storage using driver: blob.csi.azure.com

On PV, the mount option below was working when initially implemented:

mountOptions:

• nconnect=4

Then customer also migrated node from Ubuntu 'AKSUbuntu-2204gen2containerd-202402.07.0' to Azure Linux container 'AKSCBLMariner-V2gen2-202402.07.0'

When migrated to azure linux container, this mount option nconnect stopped working with following error:

"Events:
Type Reason Age From Message

---

Warning FailedMount invalid (x53 over 105m) kubelet MountVolume.MountDevice failed for volume 'pv-storageaccount-scan-storage' : rpc error: code = Internal desc = volume(storageaccount_scan-storage) mount 'storageaccount.blob.core.windows.net:/storageaccount/scan-storage' on '/var/lib/kubelet/plugins/kubernetes.io/csi/blob.csi.azure.com/8a489e0c9e233fe5a00d534e8902b988a4aa747978adaabd93c13d09ccb64ebb/globalmount' failed with mount failed: exit status 1
Mounting command: mount
Mounting arguments: -t aznfs -o nconnect=4,sec=sys,vers=3,nolock storageaccount.blob.core.windows.net:/storageaccount/scan-storage /var/lib/kubelet/plugins/kubernetes.io/csi/blob.csi.azure.com/8a489e0c9e233fe5a00d534e8902b988a4aa747978adaabd93c13d09ccb64ebb/globalmount
Output: /opt/microsoft/aznfs/mountscript.sh: line 80: modprobe: command not found
nconnect option needs NFS client with Azure nconnect support!
Mount failed!
Please refer to http://aka.ms/blobmounterror for possible causes and solutions for mount errors. "

What you expected to happen:

How to reproduce it:

Anything else we need to know?:

Environment:

• CSI Driver version:
• Kubernetes version (use kubectl version):
• OS (e.g. from /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others:

[cvvz]

We need to figure out why there is no /sys/module/sunrpc/parameters/enable_azure_nconnect on Azure Linux, since without this file, we can't mount using nconnect option.

[andyzhangx]

after confirm with blob nfs v3 team, nconect on Azure Linux is not supported, if users want to use nconnect option to improve perf, then they need to use Ubunut node