ceph-volume: support symlinks as devices

This makes ceph-volume support passing symlinks as devices.

Fixes: https://tracker.ceph.com/issues/49103

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>

src/ceph-volume/ceph_volume/devices/lvm/batch.py

@@ -73,7 +73,8 @@ def get_physical_osds(devices, args):
                                      abs_size,
                                      args.osds_per_device,
                                      osd_id,
-                                     'dmcrypt' if args.dmcrypt else None))
+                                     'dmcrypt' if args.dmcrypt else None,
+                                     dev.symlink))
     return ret
 
 
@@ -568,7 +569,8 @@ def __init__(self,
                      abs_size,
                      slots,
                      id_,
-                     encryption):
+                     encryption,
+                     symlink=None):
             self.id_ = id_
             self.data = self.VolSpec(path=data_path,
                                 rel_size=rel_size,
@@ -578,6 +580,7 @@ def __init__(self,
             self.fast = None
             self.very_fast = None
             self.encryption = encryption
+            self.symlink = symlink
 
         def add_fast_device(self, path, rel_size, abs_size, slots, type_):
             self.fast = self.VolSpec(path=path,
@@ -629,9 +632,12 @@ def report(self):
             if self.encryption:
                 report += templates.osd_encryption.format(
                     enc=self.encryption)
+            path = self.data.path
+            if self.symlink:
+                path = f'{self.symlink} -> {self.data.path}'
             report += templates.osd_component.format(
                 _type=self.data.type_,
-                path=self.data.path,
+                path=path,
                 size=self.data.abs_size,
                 percent=self.data.rel_size)
             if self.fast:

src/ceph-volume/ceph_volume/tests/conftest.py

@@ -63,6 +63,7 @@ def mock_device():
     dev.path = '/dev/foo'
     dev.vg_name = 'vg_foo'
     dev.lv_name = 'lv_foo'
+    dev.symlink = None
     dev.vgs = [lvm.VolumeGroup(vg_name=dev.vg_name, lv_name=dev.lv_name)]
     dev.available_lvm = True
     dev.vg_size = [21474836480]

src/ceph-volume/ceph_volume/tests/util/test_device.py

@@ -276,6 +276,40 @@ def test_reject_not_acceptable_device(self, fake_call, device_info):
         disk = device.Device("/dev/dm-0")
         assert not disk.available
 
+    @patch("ceph_volume.util.disk.has_bluestore_label", lambda x: False)
+    @patch('ceph_volume.util.device.os.path.realpath')
+    @patch('ceph_volume.util.device.os.path.islink')
+    def test_accept_symlink_to_device(self,
+                                      m_os_path_islink,
+                                      m_os_path_realpath,
+                                      device_info,
+                                      fake_call):
+        m_os_path_islink.return_value = True
+        m_os_path_realpath.return_value = '/dev/sdb'
+        data = {"/dev/sdb": {"ro": 0, "size": 5368709120}}
+        lsblk = {"TYPE": "disk"}
+        device_info(devices=data,lsblk=lsblk)
+        disk = device.Device("/dev/test_symlink")
+        print(disk)
+        print(disk.sys_api)
+        assert disk.available
+
+    @patch("ceph_volume.util.disk.has_bluestore_label", lambda x: False)
+    @patch('ceph_volume.util.device.os.readlink')
+    @patch('ceph_volume.util.device.os.path.islink')
+    def test_reject_symlink_to_device_mapper(self,
+                                             m_os_path_islink,
+                                             m_os_readlink,
+                                             device_info,
+                                             fake_call):
+        m_os_path_islink.return_value = True
+        m_os_readlink.return_value = '/dev/dm-0'
+        data = {"/dev/mapper/mpatha": {"ro": 0, "size": 5368709120}}
+        lsblk = {"TYPE": "disk"}
+        device_info(devices=data,lsblk=lsblk)
+        disk = device.Device("/dev/mapper/mpatha")
+        assert disk.available
+
     @patch("ceph_volume.util.disk.has_bluestore_label", lambda x: False)
     def test_reject_readonly_device(self, fake_call, device_info):
         data = {"/dev/cdrom": {"ro": 1}}

src/ceph-volume/ceph_volume/util/device.py

@@ -99,6 +99,15 @@ class Device(object):
 
     def __init__(self, path, with_lsm=False, lvs=None, lsblk_all=None, all_devices_vgs=None):
         self.path = path
+        # LVs can have a vg/lv path, while disks will have /dev/sda
+        self.symlink = None
+        # check if we are a symlink
+        if os.path.islink(self.path):
+            self.symlink = self.path
+            real_path = os.path.realpath(self.path)
+            # check if we are not a device mapper
+            if "dm-" not in real_path:
+                self.path = real_path
         if not sys_info.devices:
             sys_info.devices = disk.get_devices()
         self.sys_api = sys_info.devices.get(self.path, {})