5016627f04
Spec repos do not have code to unit test. The gate job definition for the py27 and py35 jobs skip if there doc only changes, which is all we will ever have in the specs repo. Therefore the one "test" we had will never be run. We were using this unit test as a check for formatting issues with the rst files. This was done before doc8 was available. Now that we can use doc8, we should just switch to running that as part of the pep8 jobs. Also fixes all the errors caught by doc8 that were not caught by our unit test check. Change-Id: Ida20764edde3a07c89703d82b41958c96548b239
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..
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This work is licensed under a Creative Commons Attribution 3.0 Unported
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License.
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http://creativecommons.org/licenses/by/3.0/legalcode
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================================================================
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Support ECKD volumes on Linux on System z
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================================================================
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https://blueprints.launchpad.net/cinder/+spec/linux-ficon-support
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FICON (Fibre Connection) is a Fibre-Channel FC-4 layer protocol. It is
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used on mainframes to attach ECKD volumes via Fibre-Channel.
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Several changes are needed in order to allow Cinder to
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manage FICON-based block storage on Linux on System z.
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Besides, support is to be added to the existing Cinder drivers
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for storage subsystems supporting ECKD (for example, IBM DS8000).
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Required support in Nova is described by a separate blueprint which is
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listed as a dependency below.
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Problem description
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===================
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FICON and FCP are Fibre-Channel FC-4 layer protocols. FICON uses a
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different scheme to address volumes, compared to FCP.
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* ECKD volumes are addressed by a Control Unit and Unit Address, rather
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than WWPN and LUN.
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* System z uses a different format for device file paths (ccw-based, rather
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than pci-based), similar to the file paths used for FCP on System z
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* ECKD volumes need to be set online and formatted before they can be
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used
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Use Cases
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=========
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Allow an end-user to create and manage Cinder block devices based upon
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FICON attached storage subsystems supporting the ECKD protocol.
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For example: create, delete, image deploy, snapshot, ..
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We will extend a Cinder driver for IBMs DS8000. Other vendors, such as
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EMC, Hitachi, or HP support ECKD, too. They are potential candidates.
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Proposed change
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===============
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Change code in os-brick to address these issues, dependent on a new
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protocol type of 'fibre_channel_eckd', provided by the driver
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For details, see section `Work Items`.
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Alternatives
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------------
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None
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Data model impact
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-----------------
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None
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REST API impact
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---------------
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None
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Security impact
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---------------
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None
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Notifications impact
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--------------------
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None
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Other end user impact
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---------------------
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None
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Performance Impact
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------------------
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None
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Other deployer impact
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---------------------
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None
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Developer impact
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----------------
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Platforms that support FICON/ECKD will need to implement this for their
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drivers.
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Implementation
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==============
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Assignee(s)
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-----------
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Primary assignee:
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stefan-amann
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Other contributors:
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arecknag
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maiera
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Work Items
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----------
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In ``os-brick/initiator/connector.py``:
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* provide a new connector FibreChannelECKDConnector
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* connect_volume needs to enable interrupts for the volume and
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set the volume online. This is done by calling the new
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configure_eckd_device() function)
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* disconnect_volume needs to set the volume offline. This is done by
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calling the new deconfigure_eckd_device() function
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In ``os-brick/initiator/linuxeckd.py``:
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* Utility functions to set the volume online, validate it is formatted
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appropriately, and format it if required
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::
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def _is_online(self, device):
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"""
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Return True if device is online, else return False
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:param device: device id
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"""
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if os.access('/sys/bus/ccw/devices/%s/online' % device, os.R_OK):
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online_file = None
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try:
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online_file = open('/sys/bus/ccw/devices/%s/online' % device)
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value = online_file.readline()
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if value and value.strip() == '1':
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return True
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finally:
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if online_file:
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online_file.close()
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return False
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def _is_formatted(self, device):
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"""
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Return True if device is online, else return False
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:param device: device id
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"""
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if os.access('/sys/bus/ccw/devices/%s/status' % device, os.R_OK):
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formatted = None
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(out, _err) = self._execute('cat',
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'/sys/bus/ccw/devices/%s/status' % device,
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run_as_root=True,
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root_helper=self._root_helper)
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if out and out.strip() == 'unformatted':
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return False
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return True
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def format_eckd_volume(self, path):
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"""
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formats ECKD volume
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:param device: device path
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"""
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name = os.path.realpath(path)
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if name.startswith("/dev/"):
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format_cmd = 'dasdfmt -y -b 4096 -d ldl ' + name
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(out, _err) = self._execute(format_cmd, run_as_root=True,
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root_helper=self._root_helper)
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return True
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else:
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return False
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In ``os-brick/initiator/linuxfc.py``:
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* new class LinuxFibreChannelECKD
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.. code-block:: python
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def configure_eckd_device(self, device_number):
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"""Add the eckd volume to the Linux configuration. """
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full_device_identifier = "0.0.%04x" % device_number
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eckd_device_command = ('cio_ignore', '-r',
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'%(dev_id)s' % {"dev_id": full_device_identifier})
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LOG.debug("issue cio_ignore for s390: %s", eckd_device_command)
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out, info = None, None
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try:
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out, info = self._execute('cio_ignore', '-r',
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'%(dev_id)s' % {"dev_id": full_device_identifier},
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run_as_root=True,
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root_helper=self._root_helper)
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except putils.ProcessExecutionError as exc:
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LOG.warning(_LW("cio_ignore call for s390 failed exit"
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" %(code)s, stderr %(stderr)s"),
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{'code': exc.exit_code, 'stderr': exc.stderr})
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eckd_device_command = ('chccwdev', '-e',
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'%(dev_id)s' % {"dev_id": full_device_identifier})
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LOG.debug("add ECKD command for s390: %s", eckd_device_command)
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out, info = None, None
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try:
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out, info = self._execute('chccwdev', '-e',
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'%(dev_id)s' % {"dev_id": full_device_identifier},
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run_as_root=True,
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root_helper=self._root_helper)
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except putils.ProcessExecutionError as exc:
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LOG.warning(_LW("add ECKD call for s390 failed exit"
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" %(code)s, stderr %(stderr)s"),
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{'code': exc.exit_code, 'stderr': exc.stderr})
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def deconfigure_eckd_device(self, device_number):
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"""Remove the eckd volume from the Linux configuration. """
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LOG.debug("Deconfigure ECKD volume: device_number=%(device_num)s ",
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{'device_num': device_number})
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full_device_identifier = "0.0.%04x" % device_number
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eckd_device_command = ('chccwdev', '-d',
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'%(dev_id)s' % {"dev_id": full_device_identifier})
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LOG.debug("remove ECKD command for s390: %s", eckd_device_command)
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out, info = None, None
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try:
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out, info = self._execute('chccwdev', '-d',
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'%(dev_id)s' % {"dev_id": full_device_identifier},
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run_as_root=True,
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root_helper=self._root_helper)
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except putils.ProcessExecutionError as exc:
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LOG.warning(_LW("remove ECKD call for s390 failed exit"
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" %(code)s, stderr %(stderr)s"),
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{'code': exc.exit_code, 'stderr': exc.stderr})
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Adaptations to volume.filters to allow the new commands to be sent
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Cinder drivers need to report the Control Unit address, and Unit Address
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of the ECKD volume and set the driver_volume_type to 'fibre_channel_eckd'
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Any drivers wishing to support FICON will need to have CI reporting results
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from running against a FICON attached host.
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Dependencies
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============
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Nova blueprint to add support for ECKD for Linux on System z. The blueprint
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can be found here:
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https://blueprints.launchpad.net/nova/+spec/linux-ficon-support
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Testing
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=======
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Unit test:
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* Unit tests will be added and performed on System z, as well as
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Intel-based machines.
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CI environment:
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* We will provide a 3rd party CI environment for DS8000.
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Documentation Impact
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====================
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* We will update documentation as required.
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References
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==========
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* _`[1]` Linux on System z Device Driver book,
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http://public.dhe.ibm.com/software/dw/linux390/docu/l316dd25.pdf
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* _`[2]` Linux on System z,
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http://www.ibm.com/developerworks/linux/linux390/
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