8080 }
8181}
8282
83+ MULTIPATH_ENABLED = None
84+
8385
8486def _get_device_info (dev , devclass , field ):
8587 """Get the device info according to device class and field."""
@@ -126,6 +128,35 @@ def _udev_settle():
126128 return
127129
128130
131+ def _load_multipath_modules ():
132+ """Load multipath modules
133+
134+ This is required to be able to collect multipath information.
135+ Two separate paths exist, one with a helper utility for Centos/RHEL
136+ and another which is just load the modules, and trust multipathd
137+ will do the needful.
138+ """
139+ if (os .path .isfile ('/usr/sbin/mpathconf' )
140+ and not os .path .isfile ('/etc/multipath.conf' )):
141+ # For Centos/Rhel/Etc which uses mpathconf, this does
142+ # a couple different things, including configuration generation...
143+ # which is not *really* required.. at least *shouldn't* be.
144+ # WARNING(TheJulia): This command explicitly replaces local
145+ # configuration.
146+ il_utils .try_execute ('/usr/sbin/mpathconf' , '--enable' ,
147+ '--find_multipaths' , 'yes' ,
148+ '--with_module' , 'y' ,
149+ '--with_multipathd' , 'y' )
150+ else :
151+ # Ensure modules are loaded. Configuration is not required
152+ # and implied based upon compiled in defaults.
153+ # NOTE(TheJulia): Debian/Ubuntu specifically just document
154+ # using `multipath -t` output to start a new configuration
155+ # file, if needed.
156+ il_utils .try_execute ('modprobe' , 'dm_multipath' )
157+ il_utils .try_execute ('modprobe' , 'multipath' )
158+
159+
129160def _check_for_iscsi ():
130161 """Connect iSCSI shared connected via iBFT or OF.
131162
@@ -169,6 +200,84 @@ def _get_md_uuid(raid_device):
169200 return match .group (1 )
170201
171202
203+ def _enable_multipath ():
204+ """Initialize multipath IO if possible.
205+
206+ :returns: True if the multipathd daemon and multipath command to enumerate
207+ devices was scucessfully able to be called.
208+ """
209+ try :
210+ _load_multipath_modules ()
211+ # This might not work, ideally it *should* already be running...
212+ # NOTE(TheJulia): Testing locally, a prior running multipathd, the
213+ # explicit multipathd start just appears to silently exit with a
214+ # result code of 0.
215+ utils .execute ('multipathd' )
216+ # This is mainly to get the system to actually do the needful and
217+ # identify/enumerate paths by combining what it can detect and what
218+ # it already knows. This may be useful, and in theory this should be
219+ # logged in the IPA log should it be needed.
220+ utils .execute ('multipath' , '-ll' )
221+ return True
222+ except FileNotFoundError as e :
223+ LOG .warning ('Attempted to determine if multipath tools were present. '
224+ 'Not detected. Error recorded: %s' , e )
225+ return False
226+ except processutils .ProcessExecutionError as e :
227+ LOG .warning ('Attempted to invoke multipath utilities, but we '
228+ 'encountered an error: %s' , e )
229+ return False
230+
231+
232+ def _get_multipath_parent_device (device ):
233+ """Check and return a multipath device."""
234+ if not device :
235+ # if lsblk provides invalid output, this can be None.
236+ return
237+ check_device = os .path .join ('/dev' , str (device ))
238+ try :
239+ # Explicitly run the check as regardless of if the device is mpath or
240+ # not, multipath tools when using list always exits with a return
241+ # code of 0.
242+ utils .execute ('multipath' , '-c' , check_device )
243+ # path check with return an exit code of 1 if you send it a multipath
244+ # device mapper device, like dm-0.
245+ # NOTE(TheJulia): -ll is supposed to load from all available
246+ # information, but may not force a rescan. It may be -f if we need
247+ # that. That being said, it has been about a decade since I was
248+ # running multipath tools on SAN connected gear, so my memory is
249+ # definitely fuzzy.
250+ out , _ = utils .execute ('multipath' , '-ll' , check_device )
251+ except processutils .ProcessExecutionError as e :
252+ # FileNotFoundError if the utility does not exist.
253+ # -1 return code if the device is not valid.
254+ LOG .debug ('Checked device %(dev)s and determined it was '
255+ 'not a multipath device. %(error)s' ,
256+ {'dev' : check_device ,
257+ 'error' : e })
258+ return
259+ except FileNotFoundError :
260+ # This should never happen, as MULTIPATH_ENABLED would be False
261+ # before this occurs.
262+ LOG .warning ('Attempted to check multipathing status, however '
263+ 'the \' multipath\' binary is missing or not in the '
264+ 'execution PATH.' )
265+ return
266+ # Data format:
267+ # MPATHDEVICENAME dm-0 TYPE,HUMANNAME
268+ # size=56G features='1 retain_attached_hw_handler' hwhandler='0' wp=rw
269+ # `-+- policy='service-time 0' prio=1 status=active
270+ # `- 0:0:0:0 sda 8:0 active ready running
271+ try :
272+ lines = out .splitlines ()
273+ mpath_device = lines [0 ].split (' ' )[1 ]
274+ # give back something like dm-0 so we can log it.
275+ return mpath_device
276+ except IndexError :
277+ # We didn't get any command output, so Nope.
278+ pass
279+
280+
172281def _get_component_devices (raid_device ):
173282 """Get the component devices of a Software RAID device.
174283
@@ -359,7 +468,8 @@ def _md_scan_and_assemble():
359468def list_all_block_devices (block_type = 'disk' ,
360469 ignore_raid = False ,
361470 ignore_floppy = True ,
362- ignore_empty = True ):
471+ ignore_empty = True ,
472+ ignore_multipath = False ):
363473 """List all physical block devices
364474
365475 The switches we use for lsblk: P for KEY="value" output, b for size output
@@ -376,6 +486,9 @@ def list_all_block_devices(block_type='disk',
376486 :param ignore_floppy: Ignore floppy disk devices in the block device
377487 list. By default, these devices are filtered out.
378488 :param ignore_empty: Whether to ignore disks with size equal 0.
489+ :param ignore_multipath: Whether to ignore devices backing multipath
490+ devices. Default is to consider multipath
491+ devices, if possible.
379492 :return: A list of BlockDevices
380493 """
381494
@@ -386,6 +499,8 @@ def _is_known_device(existing, new_device_name):
386499 return True
387500 return False
388501
502+ check_multipath = not ignore_multipath and get_multipath_status ()
503+
389504 _udev_settle ()
390505
391506 # map device names to /dev/disk/by-path symbolic links that points to it
@@ -416,7 +531,6 @@ def _is_known_device(existing, new_device_name):
416531 '-o{}' .format (',' .join (columns )))[0 ]
417532 lines = report .splitlines ()
418533 context = pyudev .Context ()
419-
420534 devices = []
421535 for line in lines :
422536 device = {}
@@ -438,16 +552,31 @@ def _is_known_device(existing, new_device_name):
438552 LOG .debug ('Ignoring floppy disk device %s' , device )
439553 continue
440554
555+ dev_kname = device .get ('KNAME' )
556+ if check_multipath :
557+ # Net effect is we ignore base devices, and their base devices
558+ # to what would be the mapped device name which would not pass the
559+ # validation, but would otherwise be match-able.
560+ mpath_parent_dev = _get_multipath_parent_device (dev_kname )
561+ if mpath_parent_dev :
562+ LOG .warning (
563+ "We have identified a multipath device %(device)s, this "
564+ "is being ignored in favor of %(mpath_device)s and its "
565+ "related child devices." ,
566+ {'device' : dev_kname ,
567+ 'mpath_device' : mpath_parent_dev })
568+ continue
441569 # Search for raid in the reply type, as RAID is a
442570 # disk device, and we should honor it if is present.
443571 # Other possible type values, which we skip recording:
444572 # lvm, part, rom, loop
573+
445574 if devtype != block_type :
446575 if devtype is None or ignore_raid :
447576 LOG .debug ("Skipping: {!r}" .format (line ))
448577 continue
449578 elif ('raid' in devtype
450- and block_type in ['raid' , 'disk' ]):
579+ and block_type in ['raid' , 'disk' , 'mpath' ]):
451580 LOG .debug (
452581 "TYPE detected to contain 'raid', signifying a "
453582 "RAID volume. Found: {!r}" .format (line ))
@@ -461,6 +590,11 @@ def _is_known_device(existing, new_device_name):
461590 LOG .debug (
462591 "TYPE detected to contain 'md', signifying a "
463592 "RAID partition. Found: {!r}" .format (line ))
593+ elif devtype == 'mpath' and block_type == 'disk' :
594+ LOG .debug (
595+ "TYPE detected to contain 'mpath', "
596+ "signifing a device mapper multipath device. "
597+ "Found: %s" , line )
464598 else :
465599 LOG .debug (
466600 "TYPE did not match. Wanted: {!r} but found: {!r}" .format (
@@ -974,6 +1108,10 @@ def evaluate_hardware_support(self):
9741108 # Do some initialization before we declare ourself ready
9751109 _check_for_iscsi ()
9761110 _md_scan_and_assemble ()
1111+ global MULTIPATH_ENABLED
1112+ if MULTIPATH_ENABLED is None :
1113+ MULTIPATH_ENABLED = _enable_multipath ()
1114+
9771115 self .wait_for_disks ()
9781116 return HardwareSupport .GENERIC
9791117
@@ -2609,3 +2747,11 @@ def deduplicate_steps(candidate_steps):
26092747 deduped_steps [manager ].append (winning_step )
26102748
26112749 return deduped_steps
2750+
2751+
2752+ def get_multipath_status ():
2753+ """Return the status of multipath initialization."""
2754+ # NOTE(TheJulia): Provides a nice place to mock out and simplify testing
2755+ # as if we directly try and work with the global var, we will be racing
2756+ # tests endlessly.
2757+ return MULTIPATH_ENABLED
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