Uploaded image for project: 'OpenShift Bugs'
  1. OpenShift Bugs
  2. OCPBUGS-55184

Can't use WWN to select between multipath disks

XMLWordPrintable

    • Quality / Stability / Reliability
    • False
    • Hide

      None

      Show
      None
    • None
    • Moderate
    • No
    • None
    • None
    • Agent Sprint 270
    • 1
    • Done
    • Bug Fix
    • Hide
      * Previously, the Assisted Installer failed to detect World Wide Name (WWN) details during Fibre Channel multipath volumes hardware discovery. As a result, a Fibre Channel multipath disk could not be matched with a WWN root device. This meant that when you specified a `wwn` root device hint, the hint excluded all Fibre Channel multipath disks. With this release, the Assisted Installer now detects WWN details during Fibre Channel multipath disk discovery. If multiple Fibre Channel multipath disks exist, you can now use the `wwn` root device hint to choose a primary disk for your cluster. (link:https://issues.redhat.com/browse/OCPBUGS-55184[OCPBUGS-55184])
      Show
      * Previously, the Assisted Installer failed to detect World Wide Name (WWN) details during Fibre Channel multipath volumes hardware discovery. As a result, a Fibre Channel multipath disk could not be matched with a WWN root device. This meant that when you specified a `wwn` root device hint, the hint excluded all Fibre Channel multipath disks. With this release, the Assisted Installer now detects WWN details during Fibre Channel multipath disk discovery. If multiple Fibre Channel multipath disks exist, you can now use the `wwn` root device hint to choose a primary disk for your cluster. (link: https://issues.redhat.com/browse/OCPBUGS-55184 [ OCPBUGS-55184 ])
    • None
    • None
    • None
    • None

      This is a clone of issue OCPBUGS-54369. The following is the description of the original issue:

      This is a clone of issue OCPBUGS-52994. The following is the description of the original issue:

      When a (Fibre Channel) multipath disk is discovered by the assisted-installer-agent, the wwn field is not included:

        {
          "bootable": true,
          "by_id": "/dev/disk/by-id/wwn-0xdeadbeef",
          "drive_type": "Multipath",
          "has_uuid": true,
          "holders": "dm-3,dm-5,dm-7",
          "id": "/dev/disk/by-id/wwn-0xdeadbeef",
          "installation_eligibility": {
            "eligible": true,
            "not_eligible_reasons": null
          },
          "name": "dm-2",
          "path": "/dev/dm-2",
          "size_bytes": 549755813888
        }, 

      Thus there is no way to match this disk with a wwn: root device hint. Since assisted does not allow installing directly to a fibre channel disk (without multipath) until 4.19 with MGMT-19631, and there is no /dev/disk/by-path/ symlink for a multipath device, this means that when there are multiple multipath disks in the system there is no way to select between them other than by size.

      When ghw lists the disks, it fills in the WWN field from the ID_WWN_WITH_EXTENSION or ID_WWN udev values. It's not clear to me how udev is creating the /dev/disk/by-id/ symlink without those fields. There is a separate DM_WWN field (DM = Device Mapper), but I don't see it used in udev rules for whole disks, only for partitions. I don't have access to any hardware so it's impossible to say what the data in /run/udev/data looks like.

              ppinjark@redhat.com pawan pinjarkar
              openshift-crt-jira-prow OpenShift Prow Bot
              None
              None
              zhenying niu zhenying niu
              None
              Votes:
              0 Vote for this issue
              Watchers:
              5 Start watching this issue

                Created:
                Updated:
                Resolved: