mirror of
https://github.com/ceph/ceph
synced 2024-12-22 11:31:55 +00:00
93 lines
3.5 KiB
ReStructuredText
93 lines
3.5 KiB
ReStructuredText
.. _ceph-volume-lvm-activate:
|
|
|
|
``activate``
|
|
============
|
|
Once :ref:`ceph-volume-lvm-prepare` is completed, and all the various steps
|
|
that entails are done, the volume is ready to get "activated".
|
|
|
|
This activation process enables a systemd unit that persists the OSD ID and its
|
|
UUID (also called ``fsid`` in Ceph CLI tools), so that at boot time it can
|
|
understand what OSD is enabled and needs to be mounted.
|
|
|
|
.. note:: The execution of this call is fully idempotent, and there is no
|
|
side-effects when running multiple times
|
|
|
|
New OSDs
|
|
--------
|
|
To activate newly prepared OSDs both the :term:`OSD id` and :term:`OSD uuid`
|
|
need to be supplied. For example::
|
|
|
|
ceph-volume lvm activate --bluestore 0 0263644D-0BF1-4D6D-BC34-28BD98AE3BC8
|
|
|
|
.. note:: The UUID is stored in the ``fsid`` file in the OSD path, which is
|
|
generated when :ref:`ceph-volume-lvm-prepare` is used.
|
|
|
|
requiring uuids
|
|
^^^^^^^^^^^^^^^
|
|
The :term:`OSD uuid` is being required as an extra step to ensure that the
|
|
right OSD is being activated. It is entirely possible that a previous OSD with
|
|
the same id exists and would end up activating the incorrect one.
|
|
|
|
|
|
Discovery
|
|
---------
|
|
With OSDs previously created by ``ceph-volume``, a *discovery* process is
|
|
performed using :term:`LVM tags` to enable the systemd units.
|
|
|
|
The systemd unit will capture the :term:`OSD id` and :term:`OSD uuid` and
|
|
persist it. Internally, the activation will enable it like::
|
|
|
|
systemctl enable ceph-volume@lvm-$id-$uuid
|
|
|
|
For example::
|
|
|
|
systemctl enable ceph-volume@lvm-0-8715BEB4-15C5-49DE-BA6F-401086EC7B41
|
|
|
|
Would start the discovery process for the OSD with an id of ``0`` and a UUID of
|
|
``8715BEB4-15C5-49DE-BA6F-401086EC7B41``.
|
|
|
|
.. note:: for more details on the systemd workflow see :ref:`ceph-volume-lvm-systemd`
|
|
|
|
The systemd unit will look for the matching OSD device, and by looking at its
|
|
:term:`LVM tags` will proceed to:
|
|
|
|
# mount the device in the corresponding location (by convention this is
|
|
``/var/lib/ceph/osd/<cluster name>-<osd id>/``)
|
|
|
|
# ensure that all required devices are ready for that OSD. In the case of
|
|
a journal (when ``--filestore`` is selected) the device will be queried (with
|
|
``blkid`` for partitions, and lvm for logical volumes) to ensure that the
|
|
correct device is being linked. The symbolic link will *always* be re-done to
|
|
ensure that the correct device is linked.
|
|
|
|
# start the ``ceph-osd@0`` systemd unit
|
|
|
|
.. note:: The system infers the objectstore type (filestore or bluestore) by
|
|
inspecting the LVM tags applied to the OSD devices
|
|
|
|
Existing OSDs
|
|
-------------
|
|
For existing OSDs that have been deployed with different tooling, the only way
|
|
to port them over to the new mechanism is to prepare them again (losing data).
|
|
See :ref:`ceph-volume-lvm-existing-osds` for details on how to proceed.
|
|
|
|
Summary
|
|
-------
|
|
To recap the ``activate`` process for :term:`bluestore`:
|
|
|
|
#. require both :term:`OSD id` and :term:`OSD uuid`
|
|
#. enable the system unit with matching id and uuid
|
|
#. Create the ``tmpfs`` mount at the OSD directory in
|
|
``/var/lib/ceph/osd/$cluster-$id/``
|
|
#. Recreate all the files needed with ``ceph-bluestore-tool prime-osd-dir`` by
|
|
pointing it to the OSD ``block`` device.
|
|
#. the systemd unit will ensure all devices are ready and linked
|
|
#. the matching ``ceph-osd`` systemd unit will get started
|
|
|
|
And for :term:`filestore`:
|
|
|
|
#. require both :term:`OSD id` and :term:`OSD uuid`
|
|
#. enable the system unit with matching id and uuid
|
|
#. the systemd unit will ensure all devices are ready and mounted (if needed)
|
|
#. the matching ``ceph-osd`` systemd unit will get started
|