97 lines
3.6 KiB
PHP
97 lines
3.6 KiB
PHP
.. _root-device-hints:
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Specifying the disk for deployment (root device hints)
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------------------------------------------------------
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The Bare Metal service supports passing hints to the deploy ramdisk about
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which disk it should pick for the deployment. The list of supported hints is:
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* model (STRING): device identifier
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* vendor (STRING): device vendor
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* serial (STRING): disk serial number
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* size (INT): size of the device in GiB
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.. note::
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A node's 'local_gb' property is often set to a value 1 GiB less than the
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actual disk size to account for partitioning (this is how DevStack, TripleO
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and Ironic Inspector work, to name a few). However, in this case ``size``
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should be the actual size. For example, for a 128 GiB disk ``local_gb``
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will be 127, but size hint will be 128.
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* wwn (STRING): unique storage identifier
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* wwn_with_extension (STRING): unique storage identifier with the vendor extension appended
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* wwn_vendor_extension (STRING): unique vendor storage identifier
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* rotational (BOOLEAN): whether it's a rotational device or not. This
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hint makes it easier to distinguish HDDs (rotational) and SSDs (not
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rotational) when choosing which disk Ironic should deploy the image onto.
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* hctl (STRING): the SCSI address (Host, Channel, Target and Lun),
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e.g '1:0:0:0'
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* name (STRING): the device name, e.g /dev/md0
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.. warning::
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The root device hint name should only be used for devices with
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constant names (e.g RAID volumes). For SATA, SCSI and IDE disk
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controllers this hint is not recommended because the order in which
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the device nodes are added in Linux is arbitrary, resulting in
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devices like /dev/sda and /dev/sdb `switching around at boot time
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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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To associate one or more hints with a node, update the node's properties
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with a ``root_device`` key, for example::
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baremetal node set <node-uuid> --property root_device='{"wwn": "0x4000cca77fc4dba1"}'
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That will guarantee that Bare Metal service will pick the disk device that
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has the ``wwn`` equal to the specified wwn value, or fail the deployment if it
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can not be found.
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.. note::
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Starting with the Ussuri release, root device hints can be specified
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per-instance, see :doc:`/install/standalone`.
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The hints can have an operator at the beginning of the value string. If
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no operator is specified the default is ``==`` (for numerical values)
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and ``s==`` (for string values). The supported operators are:
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* For numerical values:
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* ``=`` equal to or greater than. This is equivalent to ``>=`` and is
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supported for `legacy reasons <https://docs.openstack.org/nova/latest/user/filter-scheduler.html#filtering>`_
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* ``==`` equal to
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* ``!=`` not equal to
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* ``>=`` greater than or equal to
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* ``>`` greater than
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* ``<=`` less than or equal to
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* ``<`` less than
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* For strings (as python comparisons):
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* ``s==`` equal to
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* ``s!=`` not equal to
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* ``s>=`` greater than or equal to
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* ``s>`` greater than
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* ``s<=`` less than or equal to
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* ``s<`` less than
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* ``<in>`` substring
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* For collections:
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* ``<all-in>`` all elements contained in collection
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* ``<or>`` find one of these
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Examples are:
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* Finding a disk larger or equal to 60 GiB and non-rotational (SSD)::
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baremetal node set <node-uuid> --property root_device='{"size": ">= 60", "rotational": false}'
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* Finding a disk whose vendor is ``samsung`` or ``winsys``::
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baremetal node set <node-uuid> --property root_device='{"vendor": "<or> samsung <or> winsys"}'
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.. note::
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If multiple hints are specified, a device must satisfy all the hints.
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