ceph-volume lvm.common create a rollback_osd utility to cleanup failed osd prepare/create calls

Signed-off-by: Alfredo Deza <adeza@redhat.com>
(cherry picked from commit e533792e0d)

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

@@ -1,7 +1,43 @@
 from ceph_volume.util import arg_validators
+from ceph_volume import process
+from ceph_volume import terminal
 import argparse
 
 
+def rollback_osd(args, osd_id=None):
+    """
+    When the process of creating or preparing fails, the OSD needs to be either
+    purged (ID fully removed) or destroyed (ID persists). This is important
+    because otherwise it would leave the ID around, which can cause confusion
+    if relying on the automatic (OSD.N + 1) behavior.
+
+    When the OSD id is specified in the command line explicitly (with
+    ``--osd-id``) , the the ID is then preserved with a soft removal (``ceph
+    osd destroy``), otherwise it is fully removed with ``purge``.
+    """
+    if not osd_id:
+        # it means that it wasn't generated, so there is nothing to rollback here
+        return
+
+    # once here, this is an error condition that needs to be rolled back
+    terminal.error('Was unable to complete a new OSD, will rollback changes')
+    osd_name = 'osd.%s'
+    if args.osd_id is None:
+        terminal.error('OSD will be fully purged from the cluster, because the ID was generated')
+        # the ID wasn't passed in explicitly, so make sure it is fully removed
+        process.run([
+            'ceph', 'osd', 'purge',
+            osd_name % osd_id,
+            '--yes-i-really-mean-it'])
+    else:
+        terminal.error('OSD will be destroyed, keeping the ID because it was provided with --osd-id')
+        # the ID was passed explicitly, so allow to re-use by using `destroy`
+        process.run([
+            'ceph', 'osd', 'destroy',
+            osd_name % args.osd_id,
+            '--yes-i-really-mean-it'])
+
+
 def common_parser(prog, description):
     """
     Both prepare and create share the same parser, those are defined here to