107 lines
4.2 KiB
ReStructuredText
107 lines
4.2 KiB
ReStructuredText
.. _root_device:
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Setting the Root Device for Deployment
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--------------------------------------
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If your hardware has several hard drives, it's highly recommended that you
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specify the exact device to be used during introspection and deployment
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as a root device. This is done by setting a ``root_device`` property on the
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node in Ironic. Please refer to the `Ironic root device hints documentation`_
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for more details.
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For example::
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baremetal node set <UUID> --property root_device='{"wwn": "0x4000cca77fc4dba1"}'
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To remove a hint and fallback to the default behavior::
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baremetal node unset <UUID> --property root_device
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Note that the root device hints should be assigned *before* both introspection
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and deployment. After changing the root device hints you should either re-run
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introspection or manually fix the ``local_gb`` property for a node::
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baremetal node set <UUID> --property local_gb=<NEW VALUE>
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Where the new value is calculated as a real disk size in GiB minus 1 GiB to
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account for partitioning (the introspection process does this calculation
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automatically).
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Setting root device hints automatically
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Starting with the Newton release it is possible to autogenerate root
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device hints for all nodes instead of setting them one by one. Pass the
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``--root-device`` argument to the ``openstack overcloud node
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configure`` **after a successful introspection**. This argument can
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accept a device list in the order of preference, for example::
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openstack overcloud node configure --all-manageable --root-device=sdb,sdc,vda
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It can also accept one of two strategies: ``smallest`` will pick the smallest
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device, ``largest`` will pick the largest one. By default only disk devices
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larger than 4 GiB are considered at all, set the ``--root-device-minimum-size``
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argument to change.
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.. note::
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Subsequent runs of this command on the same set of nodes does nothing,
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as root device hints are already recorded on nodes and are not overwritten.
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If you want to change existing root device hints, first remove them manually
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as described above.
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.. note::
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This command relies on introspection data, so if you change disk devices on
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the machines, introspection must be rerun before rerunning this command.
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Using introspection data to find the root device
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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If you don't know the information required to make a choice, you can use
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introspection to figure it out. First start with :ref:`introspection` as usual
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without setting any root device hints. Then use the stored introspection data
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to list all disk devices::
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baremetal introspection data save fdf975ae-6bd7-493f-a0b9-a0a4667b8ef3 | jq '.inventory.disks'
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For **python-ironic-inspector-client** versions older than 1.4.0 you can use
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the ``curl`` command instead, see :ref:`introspection_data` for details.
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This command will yield output similar to the following (some fields are empty
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for a virtual node)::
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[
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{
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"size": 11811160064,
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"rotational": true,
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"vendor": "0x1af4",
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"name": "/dev/vda",
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"wwn_vendor_extension": null,
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"wwn_with_extension": null,
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"model": "",
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"wwn": null,
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"serial": null
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},
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{
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"size": 11811160064,
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"rotational": true,
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"vendor": "0x1af4",
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"name": "/dev/vdb",
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"wwn_vendor_extension": null,
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"wwn_with_extension": null,
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"model": "",
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"wwn": null,
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"serial": null
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}
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]
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You can use all these fields, except for ``rotational``, for the root device
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hints. Note that ``size`` should be converted to GiB and that ``name``,
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``wwn_with_extension`` and ``wwn_vendor_extension`` can only be used starting
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with the Mitaka release. Also note that the ``name`` field, while convenient,
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`may be unreliable and change between boots
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<https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Storage_Administration_Guide/persistent_naming.html>`_.
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Do not forget to re-run the introspection after setting the root device hints.
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.. _Ironic root device hints documentation: https://docs.openstack.org/ironic/latest/install/advanced.html#specifying-the-disk-for-deployment-root-device-hints
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