Re: [PATCH v1 13/13] libceph: force host network namespace for kernel CephFS mounts

[Ionut Nechita (Wind River)]

Hi Ilya,

Thank you for the detailed feedback and the historical context around
commits 757856d2 and eea553c2 -- I wasn't aware that namespace-aware
mounting was an intentional feature.

With the full series applied (patches 1-13), the Rook-Ceph rolling
upgrade scenario (e.g., Ceph 18.2.2 -> 18.2.5) with active CephFS
workloads completes successfully. The connection recovery, sync
timeouts, and mdsmap refresh patches address the core issues.

I agree that patch 13 is a force-impact change and can be seen as a
workaround for what is likely a race condition in the CSI/kubelet
orchestration layer. I'll drop it from v2 of this series.

I'd like to collaborate to better understand the namespace interaction
with CephFS in containerized environments. I'll gather more details  
about the specific race condition and share them both here and in the
Ceph tracker bug I opened:

  https://tracker.ceph.com/issues/74897

Regarding your questions:
- The network provider is Calico (IPv6-only cluster)
- The race condition occurs during kubelet restart when ceph-csi  
  issues mount() -- in some cases the mount syscall appears 
  to execute in the context of a pod namespace rather than 
  the host namespace, though I need to investigate 
  further to provide a proper reproducer

Thanks again for the review.

Best regards,
Ionut