Olivier Gayot has proposed merging ~ogayot/curtin:raid+multipath-drop-legacy
into curtin:master.
Commit message:
block: drop legacy multipath detection mechanism
There is multiple problems with the legacy multipath detection:
* it detects IMSM RAID 1 devices as a multipath disk (false positive)
* it does not always detect actual multipath devices (false negative)
* it is used as an alternative method to detect multipath devices even
when multipath-tools does not detect any (and this leads to potential
false positives)
Let's drop this mechanism. If we want proper multipath support, we have
multipath-tools.
LP: #2094979
Requested reviews:
Server Team CI bot (server-team-bot): continuous-integration
Chris Peterson (cpete)
Related bugs:
Bug #2094979 in curtin: "curtin misidentify /dev/md126p3 as a multipath
device, generates unbootable grub config"
https://bugs.launchpad.net/curtin/+bug/2094979
For more details, see:
https://code.launchpad.net/~ogayot/curtin/+git/curtin/+merge/481411
--
Your team curtin developers is subscribed to branch curtin:master.
diff --git a/curtin/block/__init__.py b/curtin/block/__init__.py
index f0445ae..497372d 100644
--- a/curtin/block/__init__.py
+++ b/curtin/block/__init__.py
@@ -7,6 +7,7 @@ import os
import stat
import sys
import tempfile
+from typing import Optional
from curtin import util
from curtin.block import lvm
@@ -566,60 +567,6 @@ def blkid(devs=None, cache=True):
return data
-def _legacy_detect_multipath(target_mountpoint=None):
- """
- Detect if the operating system has been installed to a multipath device.
- """
- # The obvious way to detect multipath is to use multipath utility which is
- # provided by the multipath-tools package. Unfortunately, multipath-tools
- # package is not available in all ephemeral images hence we can't use it.
- # Another reasonable way to detect multipath is to look for two (or more)
- # devices with the same World Wide Name (WWN) which can be fetched using
- # scsi_id utility. This way doesn't work as well because WWNs are not
- # unique in some cases which leads to false positives which may prevent
- # system from booting (see LP: #1463046 for details).
- # Taking into account all the issues mentioned above, curent implementation
- # detects multipath by looking for a filesystem with the same UUID
- # as the target device. It relies on the fact that all alternative routes
- # to the same disk observe identical partition information including UUID.
- # There are some issues with this approach as well though. We won't detect
- # multipath disk if it doesn't any filesystems. Good news is that
- # target disk will always have a filesystem because curtin creates them
- # while installing the system.
- rescan_block_devices()
- binfo = blkid(cache=False)
- LOG.debug("legacy_detect_multipath found blkid info: %s", binfo)
- # get_devices_for_mp may return multiple devices by design. It is not yet
- # implemented but it should return multiple devices when installer creates
- # separate disk partitions for / and /boot. We need to do UUID-based
- # multipath detection against each of target devices.
- target_devs = get_devices_for_mp(target_mountpoint)
- LOG.debug("target_devs: %s" % target_devs)
- for devpath, data in binfo.items():
- # We need to figure out UUID of the target device first
- if devpath not in target_devs:
- continue
- # This entry contains information about one of target devices
- target_uuid = data.get('UUID')
- # UUID-based multipath detection won't work if target partition
- # doesn't have UUID assigned
- if not target_uuid:
- LOG.warn("Target partition %s doesn't have UUID assigned",
- devpath)
- continue
- LOG.debug("%s: %s" % (devpath, data.get('UUID', "")))
- # Iterating over available devices to see if any other device
- # has the same UUID as the target device. If such device exists
- # we probably installed the system to the multipath device.
- for other_devpath, other_data in binfo.items():
- if ((other_data.get('UUID') == target_uuid) and
- (other_devpath != devpath)):
- return True
- # No other devices have the same UUID as the target devices.
- # We probably installed the system to the non-multipath device.
- return False
-
-
def _device_is_multipathed(devpath):
devpath = os.path.realpath(devpath)
info = udevadm_info(devpath)
@@ -668,7 +615,7 @@ def md_get_devices_list(devpath):
return _md_get_members_list(devpath, state_is_not_spare)
-def detect_multipath(target_mountpoint=None):
+def detect_multipath(target_mountpoint=None) -> Optional[str]:
if multipath.multipath_supported():
for device in (os.path.realpath(dev)
for (dev, _mp, _vfs, _opts, _freq, _passno)
@@ -682,7 +629,7 @@ def detect_multipath(target_mountpoint=None):
if _device_is_multipathed(device):
return device
- return _legacy_detect_multipath(target_mountpoint)
+ return None
def get_scsi_wwid(device, replace_whitespace=False):
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