orch: disk replacement enhancement

This introduces a new `ceph orch device replace` command in order to
improve the user experience when it comes to replacing the underlying
device of an OSD.

Fixes: https://tracker.ceph.com/issues/68456

Signed-off-by: Guillaume Abrioux <[email protected]>

Author: guits

doc/cephadm/operations.rst

@@ -734,3 +734,72 @@ Purge ceph daemons from all hosts in the cluster
 
   # For each host:
   cephadm rm-cluster --force --zap-osds --fsid <fsid>
+
+
+Replacing a device
+==================
+
+The ``ceph orch device replace`` command automates the process of replacing the underlying device of an OSD.
+Previously, this process required manual intervention at various stages.
+With this new command, all necessary operations are performed automatically, streamlining the replacement process
+and improving the overall user experience.
+
+.. note:: This only supports LVM-based deployed OSD(s)
+
+.. prompt:: bash #
+
+  ceph orch device replace <host> <device-path>
+
+In the case the device being replaced is shared by multiple OSDs (eg: DB/WAL device shared by multiple OSDs), the orchestrator will warn you.
+
+.. prompt:: bash #
+
+  [ceph: root@ceph /]# ceph orch device replace osd-1 /dev/vdd
+
+  Error EINVAL: /dev/vdd is a shared device.
+  Replacing /dev/vdd implies destroying OSD(s): ['0', '1'].
+  Please, *be very careful*, this can be a very dangerous operation.
+  If you know what you are doing, pass --yes-i-really-mean-it
+
+If you know what you are doing, you can go ahead and pass ``--yes-i-really-mean-it``.
+
+.. prompt:: bash #
+
+  [ceph: root@ceph /]# ceph orch device replace osd-1 /dev/vdd --yes-i-really-mean-it
+    Scheduled to destroy osds: ['6', '7', '8'] and mark /dev/vdd as being replaced.
+
+``cephadm`` will make ``ceph-volume`` zap and destroy all related devices and mark the corresponding OSD as ``destroyed`` so the
+different OSD(s) ID(s) will be preserved:
+
+.. prompt:: bash #
+
+  [ceph: root@ceph-1 /]# ceph osd tree
+    ID  CLASS  WEIGHT   TYPE NAME         STATUS     REWEIGHT  PRI-AFF
+    -1         0.97659  root default
+    -3         0.97659      host devel-1
+     0    hdd  0.29300          osd.0     destroyed   1.00000  1.00000
+     1    hdd  0.29300          osd.1     destroyed   1.00000  1.00000
+     2    hdd  0.19530          osd.2            up   1.00000  1.00000
+     3    hdd  0.19530          osd.3            up   1.00000  1.00000
+
+The device being replaced is finally seen as ``being replaced`` preventing ``cephadm`` from redeploying the OSDs too fast:
+
+.. prompt:: bash #
+
+  [ceph: root@ceph-1 /]# ceph orch device ls
+  HOST     PATH      TYPE  DEVICE ID   SIZE  AVAILABLE  REFRESHED  REJECT REASONS
+  osd-1  /dev/vdb  hdd               200G  Yes        13s ago
+  osd-1  /dev/vdc  hdd               200G  Yes        13s ago
+  osd-1  /dev/vdd  hdd               200G  Yes        13s ago    Is being replaced
+  osd-1  /dev/vde  hdd               200G  No         13s ago    Has a FileSystem, Insufficient space (<10 extents) on vgs, LVM detected
+  osd-1  /dev/vdf  hdd               200G  No         13s ago    Has a FileSystem, Insufficient space (<10 extents) on vgs, LVM detected
+
+If for any reason you need to clear the 'device replace header' on a device, then you can use ``ceph orch device replace <host> <device> --clear``:
+
+.. prompt:: bash #
+
+  [ceph: root@devel-1 /]# ceph orch device replace devel-1 /dev/vdk --clear
+  Replacement header cleared on /dev/vdk
+  [ceph: root@devel-1 /]#
+
+After that, ``cephadm`` will redeploy the OSD service spec within a few minutes (unless the service is set to ``unmanaged``).

src/ceph-volume/ceph_volume/__init__.py

@@ -6,6 +6,7 @@
 sys_info = namedtuple('sys_info', ['devices'])
 sys_info.devices = dict()
 logger = logging.getLogger(__name__)
+BEING_REPLACED_HEADER: str = 'CEPH_DEVICE_BEING_REPLACED'
 
 
 class AllowLoopDevices:

src/ceph-volume/ceph_volume/api/lvm.py

@@ -10,6 +10,8 @@
 from math import floor
 from ceph_volume import process, util, conf
 from ceph_volume.exceptions import SizeAllocationError
+from typing import Any, Dict
+
 
 logger = logging.getLogger(__name__)
 
@@ -807,13 +809,16 @@ def get_all_devices_vgs(name_prefix=''):
                    '--units=b', '--nosuffix']
 
 
-class Volume(object):
+class Volume:
     """
     Represents a Logical Volume from LVM, with some top-level attributes like
     ``lv_name`` and parsed tags as a dictionary of key/value pairs.
     """
 
-    def __init__(self, **kw):
+    def __init__(self, **kw: str) -> None:
+        self.lv_path: str = ''
+        self.lv_name: str = ''
+        self.lv_uuid: str = ''
         for k, v in kw.items():
             setattr(self, k, v)
         self.lv_api = kw
@@ -824,13 +829,13 @@ def __init__(self, **kw):
         self.encrypted = self.tags.get('ceph.encrypted', '0') == '1'
         self.used_by_ceph = 'ceph.osd_id' in self.tags
 
-    def __str__(self):
+    def __str__(self) -> str:
         return '<%s>' % self.lv_api['lv_path']
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         return self.__str__()
 
-    def as_dict(self):
+    def as_dict(self) -> Dict[str, Any]:
         obj = {}
         obj.update(self.lv_api)
         obj['tags'] = self.tags
@@ -839,7 +844,7 @@ def as_dict(self):
         obj['path'] = self.lv_path
         return obj
 
-    def report(self):
+    def report(self) -> Dict[str, Any]:
         if not self.used_by_ceph:
             return {
                 'name': self.lv_name,