openstack-manuals/doc/config-reference/source/compute/iscsi-offload.rst
Gauvain Pocentek 26510e84dd [config-ref] Publish the RST version
Change-Id: Ia9dc15869ab201a787eecd479252282f0ae9113b
Implements: blueprint config-ref-rst
2015-12-21 09:44:24 +01:00

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iSCSI interface and offload support in Compute
==============================================
.. note::
iSCSI interface and offload support is only present since Kilo.
Compute supports open-iscsi iSCSI interfaces for offload cards.
Offload hardware must be present and configured on every compute
node where offload is desired. Once an open-iscsi interface is
configured, the iface name (``iface.iscsi_ifacename``) should be
passed to libvirt via the ``iscsi_iface`` parameter for use.
All iSCSI sessions will be bound to this iSCSI interface.
Currently supported transports (``iface.transport_name``) are
``be2iscsi``, ``bnx2i``, ``cxgb3i``, ``cxgb4i``, ``qla4xxx``, ``ocs``.
Configuration changes are required on the compute node only.
iSER is supported using the separate iSER LibvirtISERVolumeDriver
and will be rejected if used via the iscsi_iface parameter.
iSCSI iface configuration
~~~~~~~~~~~~~~~~~~~~~~~~~
* Note the distinction between the transport name (``iface.transport_name``)
and iface name (``iface.iscsi_ifacename``). The actual iface name must be
specified via the iscsi_iface parameter to libvirt for offload to work.
* The default name for an iSCSI iface (open-iscsi parameter
``iface.iscsi_ifacename``) is in the format transport_name.hwaddress
when generated by ``iscsiadm``.
* ``iscsiadm`` can be used to view and generate current iface configuration.
Every network interface that supports an open-iscsi transport can have one
or more iscsi ifaces associated with it. If no ifaces have been configured
for a network interface supported by an open-iscsi transport,
this command will create a default iface configuration for that
network interface. For example :
.. code-block:: console
# iscsiadm -m iface
default tcp,<empty>,<empty>,<empty>,<empty>
iser iser,<empty>,<empty>,<empty>,<empty>
bnx2i.00:05:b5:d2:a0:c2 bnx2i,00:05:b5:d2:a0:c2,5.10.10.20,<empty>,<empty>
The output is in the format:
``iface_name transport_name,hwaddress,ipaddress,
net_ifacename,initiatorname``.
* Individual iface configuration can be viewed via
.. code-block:: console
# iscsiadm -m iface -I IFACE_NAME
# BEGIN RECORD 2.0-873
iface.iscsi_ifacename = cxgb4i.00:07:43:28:b2:58
iface.net_ifacename = <empty>
iface.ipaddress = 102.50.50.80
iface.hwaddress = 00:07:43:28:b2:58
iface.transport_name = cxgb4i
iface.initiatorname = <empty>
# END RECORD
Configuration can be updated as desired via
.. code-block:: console
# iscsiadm -m iface-I IFACE_NAME--op=update -n iface.SETTING -v VALUE
* All iface configurations need a minimum of ``iface.iface_name``,
``iface.transport_name`` and ``iface.hwaddress`` to be correctly
configured to work. Some transports may require ``iface.ipaddress``
and ``iface.net_ifacename`` as well to bind correctly.
Detailed configuration instructions can be found at
http://www.open-iscsi.org/docs/README.