Multipath configuration may cause issues with VMware virtual disks in vSphere CSI environments

[BobVanB]

Multipath configuration and VMware virtual disks

When following generic multipath setup guides (such as for NetApp Trident with iSCSI/NFS), multipath may be enabled for all disks, including VMware virtual disks. This can lead to issues with the vSphere CSI driver:

• VMware virtual disks are presented as device-mapper devices (e.g. /dev/dm-*).
• The vSphere CSI driver expects a physical device, not a virtual device.
• This results in errors such as: /sys/devices/virtual/block/dm-*/device: no such file or directory.

Root cause:
Multipath is configured for VMware virtual disks, but multipathing for VMware should only be handled at the ESXi layer. Multipath in the guest OS is only needed for iSCSI/NFS (e.g. Trident).

Solution:
Exclude VMware virtual disks from multipath by adding a blacklist entry in your multipath.conf:

blacklist {
  device {
    vendor  "VMware"
    product "Virtual disk"
  }
}

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[k8s-ci-robot]

Hi @BobVanB. Thanks for your PR.

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[BobVanB]

/ok-to-test

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@BobVanB: Cannot trigger testing until a trusted user reviews the PR and leaves an /ok-to-test message.

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/ok-to-test

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