The UniFi VM boot-disk DataVolume (RWX + Block on longhorn-vm) failed to import:
CDI's non-root importer (UID 107, cap-drop ALL) hit
`blockdev: cannot open /dev/cdi-block-volume: Permission denied`.
Kubernetes only applies fsGroup ownership to *filesystem* volumes — it never
chowns a raw block device — and Longhorn's CSIDriver (fsGroupPolicy:
ReadWriteOnceWithFSType) skips fsGroup on RWX/Block volumes regardless, so the
device stays root:root. The CDI-documented fix is the container-runtime setting
`device_ownership_from_security_context`, exposed on k3s (>= v1.31.3+k3s1, this
cluster is v1.31.5) as `nonroot-devices: true`. It makes containerd set the
in-container device node's owner from the pod's securityContext.
Added to the Ansible-managed /etc/rancher/k3s/config.yaml alongside tls-san;
applied via the existing rolling `Restart k3s` handler (serial:1, kube-vip keeps
the API up, etcd holds 2/3). Node-scoped, security-neutral (pods stay non-root),
and preserves the longhorn-vm RWX/Block/migratable contract unchanged.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
jakman85andClaude Opus 4.8
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