Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

5 files changed, 799 insertions, 0 deletions

diff --git a/src/ceph-volume/ceph_volume/devices/simple/__init__.py b/src/ceph-volume/ceph_volume/devices/simple/__init__.py
new file mode 100644
index 000000000..280e130ed
--- /dev/null
+++ b/src/ceph-volume/ceph_volume/devices/simple/__init__.py
@@ -0,0 +1 @@
+from .main import Simple # noqa
diff --git a/src/ceph-volume/ceph_volume/devices/simple/activate.py b/src/ceph-volume/ceph_volume/devices/simple/activate.py
new file mode 100644
index 000000000..7439141c0
--- /dev/null
+++ b/src/ceph-volume/ceph_volume/devices/simple/activate.py
@@ -0,0 +1,302 @@
+from __future__ import print_function
+import argparse
+import base64
+import glob
+import json
+import logging
+import os
+from textwrap import dedent
+from ceph_volume import process, decorators, terminal, conf
+from ceph_volume.util import system, disk
+from ceph_volume.util import encryption as encryption_utils
+from ceph_volume.util import prepare as prepare_utils
+from ceph_volume.systemd import systemctl
+
+
+logger = logging.getLogger(__name__)
+mlogger = terminal.MultiLogger(__name__)
+
+
+class Activate(object):
+
+    help = 'Enable systemd units to mount configured devices and start a Ceph OSD'
+
+    def __init__(self, argv, from_trigger=False):
+        self.argv = argv
+        self.from_trigger = from_trigger
+        self.skip_systemd = False
+
+    def validate_devices(self, json_config):
+        """
+        ``json_config`` is the loaded dictionary coming from the JSON file. It is usually mixed with
+        other non-device items, but for sakes of comparison it doesn't really matter. This method is
+        just making sure that the keys needed exist
+        """
+        devices = json_config.keys()
+        try:
+            objectstore = json_config['type']
+        except KeyError:
+            if {'data', 'journal'}.issubset(set(devices)):
+                logger.warning(
+                    '"type" key not found, assuming "filestore" since journal key is present'
+                )
+                objectstore = 'filestore'
+            else:
+                logger.warning(
+                    '"type" key not found, assuming "bluestore" since journal key is not present'
+                )
+                objectstore = 'bluestore'
+
+        # Go through all the device combinations that are absolutely required,
+        # raise an error describing what was expected and what was found
+        # otherwise.
+        if objectstore == 'filestore':
+            if {'data', 'journal'}.issubset(set(devices)):
+                return True
+            else:
+                found = [i for i in devices if i in ['data', 'journal']]
+                mlogger.error("Required devices (data, and journal) not present for filestore")
+                mlogger.error('filestore devices found: %s', found)
+                raise RuntimeError('Unable to activate filestore OSD due to missing devices')
+        else:
+            # This is a bit tricky, with newer bluestore we don't need data, older implementations
+            # do (e.g. with ceph-disk). ceph-volume just uses a tmpfs that doesn't require data.
+            if {'block', 'data'}.issubset(set(devices)):
+                return True
+            else:
+                bluestore_devices = ['block.db', 'block.wal', 'block', 'data']
+                found = [i for i in devices if i in bluestore_devices]
+                mlogger.error("Required devices (block and data) not present for bluestore")
+                mlogger.error('bluestore devices found: %s', found)
+                raise RuntimeError('Unable to activate bluestore OSD due to missing devices')
+
+    def get_device(self, uuid):
+        """
+        If a device is encrypted, it will decrypt/open and return the mapper
+        path, if it isn't encrypted it will just return the device found that
+        is mapped to the uuid.  This will make it easier for the caller to
+        avoid if/else to check if devices need decrypting
+
+        :param uuid: The partition uuid of the device (PARTUUID)
+        """
+        device = disk.get_device_from_partuuid(uuid)
+
+        # If device is not found, it is fine to return an empty string from the
+        # helper that finds `device`. If it finds anything and it is not
+        # encrypted, just return what was found
+        if not self.is_encrypted or not device:
+            return device
+
+        if self.encryption_type == 'luks':
+            encryption_utils.luks_open(self.dmcrypt_secret, device, uuid)
+        else:
+            encryption_utils.plain_open(self.dmcrypt_secret, device, uuid)
+
+        return '/dev/mapper/%s' % uuid
+
+    def enable_systemd_units(self, osd_id, osd_fsid):
+        """
+        * disables the ceph-disk systemd units to prevent them from running when
+          a UDEV event matches Ceph rules
+        * creates the ``simple`` systemd units to handle the activation and
+          startup of the OSD with ``osd_id`` and ``osd_fsid``
+        * enables the OSD systemd unit and finally starts the OSD.
+        """
+        if not self.from_trigger and not self.skip_systemd:
+            # means it was scanned and now activated directly, so ensure that
+            # ceph-disk units are disabled, and that the `simple` systemd unit
+            # is created and enabled
+
+            # enable the ceph-volume unit for this OSD
+            systemctl.enable_volume(osd_id, osd_fsid, 'simple')
+
+            # disable any/all ceph-disk units
+            systemctl.mask_ceph_disk()
+            terminal.warning(
+                ('All ceph-disk systemd units have been disabled to '
+                 'prevent OSDs getting triggered by UDEV events')
+            )
+        else:
+            terminal.info('Skipping enabling of `simple` systemd unit')
+            terminal.info('Skipping masking of ceph-disk systemd units')
+
+        if not self.skip_systemd:
+            # enable the OSD
+            systemctl.enable_osd(osd_id)
+
+            # start the OSD
+            systemctl.start_osd(osd_id)
+        else:
+            terminal.info(
+                'Skipping enabling and starting OSD simple systemd unit because --no-systemd was used'
+            )
+
+    @decorators.needs_root
+    def activate(self, args):
+        with open(args.json_config, 'r') as fp:
+            osd_metadata = json.load(fp)
+
+        # Make sure that required devices are configured
+        self.validate_devices(osd_metadata)
+
+        osd_id = osd_metadata.get('whoami', args.osd_id)
+        osd_fsid = osd_metadata.get('fsid', args.osd_fsid)
+        data_uuid = osd_metadata.get('data', {}).get('uuid')
+        conf.cluster = osd_metadata.get('cluster_name', 'ceph')
+        if not data_uuid:
+            raise RuntimeError(
+                'Unable to activate OSD %s - no "uuid" key found for data' % args.osd_id
+            )
+
+        # Encryption detection, and capturing of the keys to decrypt
+        self.is_encrypted = osd_metadata.get('encrypted', False)
+        self.encryption_type = osd_metadata.get('encryption_type')
+        if self.is_encrypted:
+            lockbox_secret = osd_metadata.get('lockbox.keyring')
+            # write the keyring always so that we can unlock
+            encryption_utils.write_lockbox_keyring(osd_id, osd_fsid, lockbox_secret)
+            # Store the secret around so that the decrypt method can reuse
+            raw_dmcrypt_secret = encryption_utils.get_dmcrypt_key(osd_id, osd_fsid)
+            # Note how both these calls need b64decode. For some reason, the
+            # way ceph-disk creates these keys, it stores them in the monitor
+            # *undecoded*, requiring this decode call again. The lvm side of
+            # encryption doesn't need it, so we are assuming here that anything
+            # that `simple` scans, will come from ceph-disk and will need this
+            # extra decode call here
+            self.dmcrypt_secret = base64.b64decode(raw_dmcrypt_secret)
+
+        cluster_name = osd_metadata.get('cluster_name', 'ceph')
+        osd_dir = '/var/lib/ceph/osd/%s-%s' % (cluster_name, osd_id)
+
+        # XXX there is no support for LVM here
+        data_device = self.get_device(data_uuid)
+
+        if not data_device:
+            raise RuntimeError("osd fsid {} doesn't exist, this file will "
+                "be skipped, consider cleaning legacy "
+                "json file {}".format(osd_metadata['fsid'], args.json_config))
+
+        journal_device = self.get_device(osd_metadata.get('journal', {}).get('uuid'))
+        block_device = self.get_device(osd_metadata.get('block', {}).get('uuid'))
+        block_db_device = self.get_device(osd_metadata.get('block.db', {}).get('uuid'))
+        block_wal_device = self.get_device(osd_metadata.get('block.wal', {}).get('uuid'))
+
+        if not system.device_is_mounted(data_device, destination=osd_dir):
+            if osd_metadata.get('type') == 'filestore':
+                prepare_utils.mount_osd(data_device, osd_id)
+            else:
+                process.run(['mount', '-v', data_device, osd_dir])
+
+        device_map = {
+            'journal': journal_device,
+            'block': block_device,
+            'block.db': block_db_device,
+            'block.wal': block_wal_device
+        }
+
+        for name, device in device_map.items():
+            if not device:
+                continue
+            # always re-do the symlink regardless if it exists, so that the journal
+            # device path that may have changed can be mapped correctly every time
+            destination = os.path.join(osd_dir, name)
+            process.run(['ln', '-snf', device, destination])
+
+            # make sure that the journal has proper permissions
+            system.chown(device)
+
+        self.enable_systemd_units(osd_id, osd_fsid)
+
+        terminal.success('Successfully activated OSD %s with FSID %s' % (osd_id, osd_fsid))
+
+    def main(self):
+        sub_command_help = dedent("""
+        Activate OSDs by mounting devices previously configured to their
+        appropriate destination::
+
+            ceph-volume simple activate {ID} {FSID}
+
+        Or using a JSON file directly::
+
+            ceph-volume simple activate --file /etc/ceph/osd/{ID}-{FSID}.json
+
+        The OSD must have been "scanned" previously (see ``ceph-volume simple
+        scan``), so that all needed OSD device information and metadata exist.
+
+        A previously scanned OSD would exist like::
+
+            /etc/ceph/osd/{ID}-{FSID}.json
+
+
+        Environment variables supported:
+
+        CEPH_VOLUME_SIMPLE_JSON_DIR: Directory location for scanned OSD JSON configs
+        """)
+        parser = argparse.ArgumentParser(
+            prog='ceph-volume simple activate',
+            formatter_class=argparse.RawDescriptionHelpFormatter,
+            description=sub_command_help,
+        )
+        parser.add_argument(
+            'osd_id',
+            metavar='ID',
+            nargs='?',
+            help='The ID of the OSD, usually an integer, like 0'
+        )
+        parser.add_argument(
+            'osd_fsid',
+            metavar='FSID',
+            nargs='?',
+            help='The FSID of the OSD, similar to a SHA1'
+        )
+        parser.add_argument(
+            '--all',
+            help='Activate all OSDs with a OSD JSON config',
+            action='store_true',
+            default=False,
+        )
+        parser.add_argument(
+            '--file',
+            help='The path to a JSON file, from a scanned OSD'
+        )
+        parser.add_argument(
+            '--no-systemd',
+            dest='skip_systemd',
+            action='store_true',
+            help='Skip creating and enabling systemd units and starting OSD services',
+        )
+        if len(self.argv) == 0:
+            print(sub_command_help)
+            return
+        args = parser.parse_args(self.argv)
+        if not args.file and not args.all:
+            if not args.osd_id and not args.osd_fsid:
+                terminal.error('ID and FSID are required to find the right OSD to activate')
+                terminal.error('from a scanned OSD location in /etc/ceph/osd/')
+                raise RuntimeError('Unable to activate without both ID and FSID')
+        # don't allow a CLI flag to specify the JSON dir, because that might
+        # implicitly indicate that it would be possible to activate a json file
+        # at a non-default location which would not work at boot time if the
+        # custom location is not exposed through an ENV var
+        self.skip_systemd = args.skip_systemd
+        json_dir = os.environ.get('CEPH_VOLUME_SIMPLE_JSON_DIR', '/etc/ceph/osd/')
+        if args.all:
+            if args.file or args.osd_id:
+                mlogger.warn('--all was passed, ignoring --file and ID/FSID arguments')
+            json_configs = glob.glob('{}/*.json'.format(json_dir))
+            for json_config in json_configs:
+                mlogger.info('activating OSD specified in {}'.format(json_config))
+                args.json_config = json_config
+                try:
+                    self.activate(args)
+                except RuntimeError as e:
+                    terminal.warning(e.message)
+        else:
+            if args.file:
+                json_config = args.file
+            else:
+                json_config = os.path.join(json_dir, '%s-%s.json' % (args.osd_id, args.osd_fsid))
+            if not os.path.exists(json_config):
+                raise RuntimeError('Expected JSON config path not found: %s' % json_config)
+            args.json_config = json_config
+            self.activate(args)
diff --git a/src/ceph-volume/ceph_volume/devices/simple/main.py b/src/ceph-volume/ceph_volume/devices/simple/main.py
new file mode 100644
index 000000000..2119963f8
--- /dev/null
+++ b/src/ceph-volume/ceph_volume/devices/simple/main.py
@@ -0,0 +1,41 @@
+import argparse
+from textwrap import dedent
+from ceph_volume import terminal
+from . import scan
+from . import activate
+from . import trigger
+
+
+class Simple(object):
+
+    help = 'Manage already deployed OSDs with ceph-volume'
+
+    _help = dedent("""
+    Take over a deployed OSD, persisting its metadata in /etc/ceph/osd/ so that it can be managed
+    with ceph-volume directly. Avoids UDEV and ceph-disk handling.
+
+    {sub_help}
+    """)
+
+    mapper = {
+        'scan': scan.Scan,
+        'activate': activate.Activate,
+        'trigger': trigger.Trigger,
+    }
+
+    def __init__(self, argv):
+        self.argv = argv
+
+    def print_help(self, sub_help):
+        return self._help.format(sub_help=sub_help)
+
+    def main(self):
+        terminal.dispatch(self.mapper, self.argv)
+        parser = argparse.ArgumentParser(
+            prog='ceph-volume simple',
+            formatter_class=argparse.RawDescriptionHelpFormatter,
+            description=self.print_help(terminal.subhelp(self.mapper)),
+        )
+        parser.parse_args(self.argv)
+        if len(self.argv) <= 1:
+            return parser.print_help()
diff --git a/src/ceph-volume/ceph_volume/devices/simple/scan.py b/src/ceph-volume/ceph_volume/devices/simple/scan.py
new file mode 100644
index 000000000..ff7040beb
--- /dev/null
+++ b/src/ceph-volume/ceph_volume/devices/simple/scan.py
@@ -0,0 +1,385 @@
+from __future__ import print_function
+import argparse
+import base64
+import json
+import logging
+import os
+from textwrap import dedent
+from ceph_volume import decorators, terminal, conf
+from ceph_volume.api import lvm
+from ceph_volume.systemd import systemctl
+from ceph_volume.util import arg_validators, system, disk, encryption
+from ceph_volume.util.device import Device
+
+
+logger = logging.getLogger(__name__)
+
+
+def parse_keyring(file_contents):
+    """
+    Extract the actual key from a string. Usually from a keyring file, where
+    the keyring will be in a client section. In the case of a lockbox, it is
+    something like::
+
+        [client.osd-lockbox.8d7a8ab2-5db0-4f83-a785-2809aba403d5]\n\tkey = AQDtoGha/GYJExAA7HNl7Ukhqr7AKlCpLJk6UA==\n
+
+    From the above case, it would return::
+
+        AQDtoGha/GYJExAA7HNl7Ukhqr7AKlCpLJk6UA==
+    """
+    # remove newlines that might be trailing
+    keyring = file_contents.strip('\n')
+
+    # Now split on spaces
+    keyring = keyring.split(' ')[-1]
+
+    # Split on newlines
+    keyring = keyring.split('\n')[-1]
+
+    return keyring.strip()
+
+
+class Scan(object):
+
+    help = 'Capture metadata from all running ceph-disk OSDs, OSD data partition or directory'
+
+    def __init__(self, argv):
+        self.argv = argv
+        self._etc_path = '/etc/ceph/osd/'
+
+    @property
+    def etc_path(self):
+        if os.path.isdir(self._etc_path):
+            return self._etc_path
+
+        if not os.path.exists(self._etc_path):
+            os.mkdir(self._etc_path)
+            return self._etc_path
+
+        error = "OSD Configuration path (%s) needs to be a directory" % self._etc_path
+        raise RuntimeError(error)
+
+    def get_contents(self, path):
+        with open(path, 'r') as fp:
+            contents = fp.readlines()
+        if len(contents) > 1:
+            return ''.join(contents)
+        return ''.join(contents).strip().strip('\n')
+
+    def scan_device(self, path):
+        device_metadata = {'path': None, 'uuid': None}
+        if not path:
+            return device_metadata
+        if self.is_encrypted:
+            encryption_metadata = encryption.legacy_encrypted(path)
+            device_metadata['path'] = encryption_metadata['device']
+            device_metadata['uuid'] = disk.get_partuuid(encryption_metadata['device'])
+            return device_metadata
+        # cannot read the symlink if this is tmpfs
+        if os.path.islink(path):
+            device = os.readlink(path)
+        else:
+            device = path
+        lvm_device = lvm.get_single_lv(filters={'lv_path': device})
+        if lvm_device:
+            device_uuid = lvm_device.lv_uuid
+        else:
+            device_uuid = disk.get_partuuid(device)
+
+        device_metadata['uuid'] = device_uuid
+        device_metadata['path'] = device
+
+        return device_metadata
+
+    def scan_directory(self, path):
+        osd_metadata = {'cluster_name': conf.cluster}
+        directory_files = os.listdir(path)
+        if 'keyring' not in directory_files:
+            raise RuntimeError(
+                'OSD files not found, required "keyring" file is not present at: %s' % path
+            )
+        for file_ in os.listdir(path):
+            file_path = os.path.join(path, file_)
+            file_json_key = file_
+            if file_.endswith('_dmcrypt'):
+                file_json_key = file_.rstrip('_dmcrypt')
+                logger.info(
+                    'reading file {}, stripping _dmcrypt suffix'.format(file_)
+                )
+            if os.path.islink(file_path):
+                if os.path.exists(file_path):
+                    osd_metadata[file_json_key] = self.scan_device(file_path)
+                else:
+                    msg = 'broken symlink found %s -> %s' % (file_path, os.path.realpath(file_path))
+                    terminal.warning(msg)
+                    logger.warning(msg)
+
+            if os.path.isdir(file_path):
+                continue
+
+            # the check for binary needs to go before the file, to avoid
+            # capturing data from binary files but still be able to capture
+            # contents from actual files later
+            try:
+                if system.is_binary(file_path):
+                    logger.info('skipping binary file: %s' % file_path)
+                    continue
+            except IOError:
+                logger.exception('skipping due to IOError on file: %s' % file_path)
+                continue
+            if os.path.isfile(file_path):
+                content = self.get_contents(file_path)
+                if 'keyring' in file_path:
+                    content = parse_keyring(content)
+                try:
+                    osd_metadata[file_json_key] = int(content)
+                except ValueError:
+                    osd_metadata[file_json_key] = content
+
+        # we must scan the paths again because this might be a temporary mount
+        path_mounts = system.Mounts(paths=True)
+        device = path_mounts.get_mounts().get(path)
+
+        # it is possible to have more than one device, pick the first one, and
+        # warn that it is possible that more than one device is 'data'
+        if not device:
+            terminal.error('Unable to detect device mounted for path: %s' % path)
+            raise RuntimeError('Cannot activate OSD')
+        osd_metadata['data'] = self.scan_device(device[0] if len(device) else None)
+
+        return osd_metadata
+
+    def scan_encrypted(self, directory=None):
+        device = self.encryption_metadata['device']
+        lockbox = self.encryption_metadata['lockbox']
+        encryption_type = self.encryption_metadata['type']
+        osd_metadata = {}
+        # Get the PARTUUID of the device to make sure have the right one and
+        # that maps to the data device
+        device_uuid = disk.get_partuuid(device)
+        dm_path = '/dev/mapper/%s' % device_uuid
+        # check if this partition is already mapped
+        device_status = encryption.status(device_uuid)
+
+        # capture all the information from the lockbox first, reusing the
+        # directory scan method
+        if self.device_mounts.get(lockbox):
+            lockbox_path = self.device_mounts.get(lockbox)[0]
+            lockbox_metadata = self.scan_directory(lockbox_path)
+            # ceph-disk stores the fsid as osd-uuid in the lockbox, thanks ceph-disk
+            dmcrypt_secret = encryption.get_dmcrypt_key(
+                None,  # There is no ID stored in the lockbox
+                lockbox_metadata['osd-uuid'],
+                os.path.join(lockbox_path, 'keyring')
+            )
+        else:
+            with system.tmp_mount(lockbox) as lockbox_path:
+                lockbox_metadata = self.scan_directory(lockbox_path)
+                # ceph-disk stores the fsid as osd-uuid in the lockbox, thanks ceph-disk
+                dmcrypt_secret = encryption.get_dmcrypt_key(
+                    None,  # There is no ID stored in the lockbox
+                    lockbox_metadata['osd-uuid'],
+                    os.path.join(lockbox_path, 'keyring')
+                )
+
+        if not device_status:
+            # Note how both these calls need b64decode. For some reason, the
+            # way ceph-disk creates these keys, it stores them in the monitor
+            # *undecoded*, requiring this decode call again. The lvm side of
+            # encryption doesn't need it, so we are assuming here that anything
+            # that `simple` scans, will come from ceph-disk and will need this
+            # extra decode call here
+            dmcrypt_secret = base64.b64decode(dmcrypt_secret)
+            if encryption_type == 'luks':
+                encryption.luks_open(dmcrypt_secret, device, device_uuid)
+            else:
+                encryption.plain_open(dmcrypt_secret, device, device_uuid)
+
+        # If we have a directory, use that instead of checking for mounts
+        if directory:
+            osd_metadata = self.scan_directory(directory)
+        else:
+            # Now check if that mapper is mounted already, to avoid remounting and
+            # decrypting the device
+            dm_path_mount = self.device_mounts.get(dm_path)
+            if dm_path_mount:
+                osd_metadata = self.scan_directory(dm_path_mount[0])
+            else:
+                with system.tmp_mount(dm_path, encrypted=True) as device_path:
+                    osd_metadata = self.scan_directory(device_path)
+
+        osd_metadata['encrypted'] = True
+        osd_metadata['encryption_type'] = encryption_type
+        osd_metadata['lockbox.keyring'] = parse_keyring(lockbox_metadata['keyring'])
+        return osd_metadata
+
+    @decorators.needs_root
+    def scan(self, args):
+        osd_metadata = {'cluster_name': conf.cluster}
+        osd_path = None
+        logger.info('detecting if argument is a device or a directory: %s', args.osd_path)
+        if os.path.isdir(args.osd_path):
+            logger.info('will scan directly, path is a directory')
+            osd_path = args.osd_path
+        else:
+            # assume this is a device, check if it is mounted and use that path
+            logger.info('path is not a directory, will check if mounted')
+            if system.device_is_mounted(args.osd_path):
+                logger.info('argument is a device, which is mounted')
+                mounted_osd_paths = self.device_mounts.get(args.osd_path)
+                osd_path = mounted_osd_paths[0] if len(mounted_osd_paths) else None
+
+        # argument is not a directory, and it is not a device that is mounted
+        # somewhere so temporarily mount it to poke inside, otherwise, scan
+        # directly
+        if not osd_path:
+            # check if we have an encrypted device first, so that we can poke at
+            # the lockbox instead
+            if self.is_encrypted:
+                if not self.encryption_metadata.get('lockbox'):
+                    raise RuntimeError(
+                        'Lockbox partition was not found for device: %s' % args.osd_path
+                    )
+                osd_metadata = self.scan_encrypted()
+            else:
+                logger.info('device is not mounted, will mount it temporarily to scan')
+                with system.tmp_mount(args.osd_path) as osd_path:
+                    osd_metadata = self.scan_directory(osd_path)
+        else:
+            if self.is_encrypted:
+                logger.info('will scan encrypted OSD directory at path: %s', osd_path)
+                osd_metadata = self.scan_encrypted(osd_path)
+            else:
+                logger.info('will scan OSD directory at path: %s', osd_path)
+                osd_metadata = self.scan_directory(osd_path)
+
+        osd_id = osd_metadata['whoami']
+        osd_fsid = osd_metadata['fsid']
+        filename = '%s-%s.json' % (osd_id, osd_fsid)
+        json_path = os.path.join(self.etc_path, filename)
+
+        if os.path.exists(json_path) and not args.stdout:
+            if not args.force:
+                raise RuntimeError(
+                    '--force was not used and OSD metadata file exists: %s' % json_path
+                )
+
+        if args.stdout:
+            print(json.dumps(osd_metadata, indent=4, sort_keys=True, ensure_ascii=False))
+        else:
+            with open(json_path, 'w') as fp:
+                json.dump(osd_metadata, fp, indent=4, sort_keys=True, ensure_ascii=False)
+                fp.write(os.linesep)
+            terminal.success(
+                'OSD %s got scanned and metadata persisted to file: %s' % (
+                    osd_id,
+                    json_path
+                )
+            )
+            terminal.success(
+                'To take over management of this scanned OSD, and disable ceph-disk and udev, run:'
+            )
+            terminal.success('    ceph-volume simple activate %s %s' % (osd_id, osd_fsid))
+
+        if not osd_metadata.get('data'):
+            msg = 'Unable to determine device mounted on %s' % args.osd_path
+            logger.warning(msg)
+            terminal.warning(msg)
+            terminal.warning('OSD will not be able to start without this information:')
+            terminal.warning('    "data": "/path/to/device",')
+            logger.warning('Unable to determine device mounted on %s' % args.osd_path)
+
+    def main(self):
+        sub_command_help = dedent("""
+        Scan running OSDs, an OSD directory (or data device) for files and configurations
+        that will allow to take over the management of the OSD.
+
+        Scanned OSDs will get their configurations stored in
+        /etc/ceph/osd/<id>-<fsid>.json
+
+        For an OSD ID of 0 with fsid of ``a9d50838-e823-43d6-b01f-2f8d0a77afc2``
+        that could mean a scan command that looks like::
+
+            ceph-volume simple scan /var/lib/ceph/osd/ceph-0
+
+        Which would store the metadata in a JSON file at::
+
+            /etc/ceph/osd/0-a9d50838-e823-43d6-b01f-2f8d0a77afc2.json
+
+        To scan all running OSDs:
+
+            ceph-volume simple scan
+
+        To a scan a specific running OSD:
+
+            ceph-volume simple scan /var/lib/ceph/osd/{cluster}-{osd id}
+
+        And to scan a device (mounted or unmounted) that has OSD data in it, for example /dev/sda1
+
+            ceph-volume simple scan /dev/sda1
+
+        Scanning a device or directory that belongs to an OSD not created by ceph-disk will be ingored.
+        """)
+        parser = argparse.ArgumentParser(
+            prog='ceph-volume simple scan',
+            formatter_class=argparse.RawDescriptionHelpFormatter,
+            description=sub_command_help,
+        )
+
+        parser.add_argument(
+            '-f', '--force',
+            action='store_true',
+            help='If OSD has already been scanned, the JSON file will be overwritten'
+        )
+
+        parser.add_argument(
+            '--stdout',
+            action='store_true',
+            help='Do not save to a file, output metadata to stdout'
+        )
+
+        parser.add_argument(
+            'osd_path',
+            metavar='OSD_PATH',
+            type=arg_validators.OSDPath(),
+            nargs='?',
+            default=None,
+            help='Path to an existing OSD directory or OSD data partition'
+        )
+
+        args = parser.parse_args(self.argv)
+        paths = []
+        if args.osd_path:
+            paths.append(args.osd_path)
+        else:
+            osd_ids = systemctl.get_running_osd_ids()
+            for osd_id in osd_ids:
+                paths.append("/var/lib/ceph/osd/{}-{}".format(
+                    conf.cluster,
+                    osd_id,
+                ))
+
+        # Capture some environment status, so that it can be reused all over
+        self.device_mounts = system.Mounts(devices=True).get_mounts()
+        self.path_mounts = system.Mounts(paths=True).get_mounts()
+
+        for path in paths:
+            args.osd_path = path
+            device = Device(args.osd_path)
+            if device.is_partition:
+                if device.ceph_disk.type != 'data':
+                    label = device.ceph_disk.partlabel
+                    msg = 'Device must be the ceph data partition, but PARTLABEL reported: "%s"' % label
+                    raise RuntimeError(msg)
+
+            self.encryption_metadata = encryption.legacy_encrypted(args.osd_path)
+            self.is_encrypted = self.encryption_metadata['encrypted']
+
+            if self.encryption_metadata['device'] != "tmpfs":
+                device = Device(self.encryption_metadata['device'])
+                if not device.is_ceph_disk_member:
+                    terminal.warning("Ignoring %s because it's not a ceph-disk created osd." % path)
+                else:
+                    self.scan(args)
+            else:
+                terminal.warning("Ignoring %s because it's not a ceph-disk created osd." % path)
diff --git a/src/ceph-volume/ceph_volume/devices/simple/trigger.py b/src/ceph-volume/ceph_volume/devices/simple/trigger.py
new file mode 100644
index 000000000..c01d9ae2a
--- /dev/null
+++ b/src/ceph-volume/ceph_volume/devices/simple/trigger.py
@@ -0,0 +1,70 @@
+from __future__ import print_function
+import argparse
+from textwrap import dedent
+from ceph_volume.exceptions import SuffixParsingError
+from ceph_volume import decorators
+from .activate import Activate
+
+
+def parse_osd_id(string):
+    osd_id = string.split('-', 1)[0]
+    if not osd_id:
+        raise SuffixParsingError('OSD id', string)
+    if osd_id.isdigit():
+        return osd_id
+    raise SuffixParsingError('OSD id', string)
+
+
+def parse_osd_uuid(string):
+    osd_id = '%s-' % parse_osd_id(string)
+    # remove the id first
+    osd_uuid = string.split(osd_id, 1)[-1]
+    if not osd_uuid:
+        raise SuffixParsingError('OSD uuid', string)
+    return osd_uuid
+
+
+class Trigger(object):
+
+    help = 'systemd helper to activate an OSD'
+
+    def __init__(self, argv):
+        self.argv = argv
+
+    @decorators.needs_root
+    def main(self):
+        sub_command_help = dedent("""
+        ** DO NOT USE DIRECTLY **
+        This tool is meant to help the systemd unit that knows about OSDs.
+
+        Proxy OSD activation to ``ceph-volume simple activate`` by parsing the
+        input from systemd, detecting the UUID and ID associated with an OSD::
+
+            ceph-volume simple trigger {SYSTEMD-DATA}
+
+        The systemd "data" is expected to be in the format of::
+
+            {OSD ID}-{OSD UUID}
+
+        The devices associated with the OSD need to have been scanned previously,
+        so that all needed metadata can be used for starting the OSD process.
+        """)
+        parser = argparse.ArgumentParser(
+            prog='ceph-volume simple trigger',
+            formatter_class=argparse.RawDescriptionHelpFormatter,
+            description=sub_command_help,
+        )
+
+        parser.add_argument(
+            'systemd_data',
+            metavar='SYSTEMD_DATA',
+            nargs='?',
+            help='Data from a systemd unit containing ID and UUID of the OSD, like 0-asdf-lkjh'
+        )
+        if len(self.argv) == 0:
+            print(sub_command_help)
+            return
+        args = parser.parse_args(self.argv)
+        osd_id = parse_osd_id(args.systemd_data)
+        osd_uuid = parse_osd_uuid(args.systemd_data)
+        Activate([osd_id, osd_uuid], from_trigger=True).main()