*********** OSD Service *********** .. _device management: ../rados/operations/devices .. _libstoragemgmt: https://github.com/libstorage/libstoragemgmt List Devices ============ ``ceph-volume`` scans each host in the cluster from time to time in order to determine which devices are present and whether they are eligible to be used as OSDs. To print a list of devices discovered by ``cephadm``, run this command: .. prompt:: bash # ceph orch device ls [--hostname=...] [--wide] [--refresh] Example:: Hostname Path Type Serial Size Health Ident Fault Available srv-01 /dev/sdb hdd 15P0A0YFFRD6 300G Unknown N/A N/A No srv-01 /dev/sdc hdd 15R0A08WFRD6 300G Unknown N/A N/A No srv-01 /dev/sdd hdd 15R0A07DFRD6 300G Unknown N/A N/A No srv-01 /dev/sde hdd 15P0A0QDFRD6 300G Unknown N/A N/A No srv-02 /dev/sdb hdd 15R0A033FRD6 300G Unknown N/A N/A No srv-02 /dev/sdc hdd 15R0A05XFRD6 300G Unknown N/A N/A No srv-02 /dev/sde hdd 15R0A0ANFRD6 300G Unknown N/A N/A No srv-02 /dev/sdf hdd 15R0A06EFRD6 300G Unknown N/A N/A No srv-03 /dev/sdb hdd 15R0A0OGFRD6 300G Unknown N/A N/A No srv-03 /dev/sdc hdd 15R0A0P7FRD6 300G Unknown N/A N/A No srv-03 /dev/sdd hdd 15R0A0O7FRD6 300G Unknown N/A N/A No Using the ``--wide`` option provides all details relating to the device, including any reasons that the device might not be eligible for use as an OSD. In the above example you can see fields named "Health", "Ident", and "Fault". This information is provided by integration with `libstoragemgmt`_. By default, this integration is disabled (because `libstoragemgmt`_ may not be 100% compatible with your hardware). To make ``cephadm`` include these fields, enable cephadm's "enhanced device scan" option as follows; .. prompt:: bash # ceph config set mgr mgr/cephadm/device_enhanced_scan true .. warning:: Although the libstoragemgmt library performs standard SCSI inquiry calls, there is no guarantee that your firmware fully implements these standards. This can lead to erratic behaviour and even bus resets on some older hardware. It is therefore recommended that, before enabling this feature, you test your hardware's compatibility with libstoragemgmt first to avoid unplanned interruptions to services. There are a number of ways to test compatibility, but the simplest may be to use the cephadm shell to call libstoragemgmt directly - ``cephadm shell lsmcli ldl``. If your hardware is supported you should see something like this: :: Path | SCSI VPD 0x83 | Link Type | Serial Number | Health Status ---------------------------------------------------------------------------- /dev/sda | 50000396082ba631 | SAS | 15P0A0R0FRD6 | Good /dev/sdb | 50000396082bbbf9 | SAS | 15P0A0YFFRD6 | Good After you have enabled libstoragemgmt support, the output will look something like this: :: # ceph orch device ls Hostname Path Type Serial Size Health Ident Fault Available srv-01 /dev/sdb hdd 15P0A0YFFRD6 300G Good Off Off No srv-01 /dev/sdc hdd 15R0A08WFRD6 300G Good Off Off No : In this example, libstoragemgmt has confirmed the health of the drives and the ability to interact with the Identification and Fault LEDs on the drive enclosures. For further information about interacting with these LEDs, refer to `device management`_. .. note:: The current release of `libstoragemgmt`_ (1.8.8) supports SCSI, SAS, and SATA based local disks only. There is no official support for NVMe devices (PCIe) .. _cephadm-deploy-osds: Deploy OSDs =========== Listing Storage Devices ----------------------- In order to deploy an OSD, there must be a storage device that is *available* on which the OSD will be deployed. Run this command to display an inventory of storage devices on all cluster hosts: .. prompt:: bash # ceph orch device ls A storage device is considered *available* if all of the following conditions are met: * The device must have no partitions. * The device must not have any LVM state. * The device must not be mounted. * The device must not contain a file system. * The device must not contain a Ceph BlueStore OSD. * The device must be larger than 5 GB. Ceph will not provision an OSD on a device that is not available. Creating New OSDs ----------------- There are a few ways to create new OSDs: * Tell Ceph to consume any available and unused storage device: .. prompt:: bash # ceph orch apply osd --all-available-devices * Create an OSD from a specific device on a specific host: .. prompt:: bash # ceph orch daemon add osd **:** For example: .. prompt:: bash # ceph orch daemon add osd host1:/dev/sdb Advanced OSD creation from specific devices on a specific host: .. prompt:: bash # ceph orch daemon add osd host1:data_devices=/dev/sda,/dev/sdb,db_devices=/dev/sdc,osds_per_device=2 * Create an OSD on a specific LVM logical volume on a specific host: .. prompt:: bash # ceph orch daemon add osd **:** For example: .. prompt:: bash # ceph orch daemon add osd host1:/dev/vg_osd/lvm_osd1701 * You can use :ref:`drivegroups` to categorize device(s) based on their properties. This might be useful in forming a clearer picture of which devices are available to consume. Properties include device type (SSD or HDD), device model names, size, and the hosts on which the devices exist: .. prompt:: bash # ceph orch apply -i spec.yml Dry Run ------- The ``--dry-run`` flag causes the orchestrator to present a preview of what will happen without actually creating the OSDs. For example: .. prompt:: bash # ceph orch apply osd --all-available-devices --dry-run :: NAME HOST DATA DB WAL all-available-devices node1 /dev/vdb - - all-available-devices node2 /dev/vdc - - all-available-devices node3 /dev/vdd - - .. _cephadm-osd-declarative: Declarative State ----------------- The effect of ``ceph orch apply`` is persistent. This means that drives that are added to the system after the ``ceph orch apply`` command completes will be automatically found and added to the cluster. It also means that drives that become available (by zapping, for example) after the ``ceph orch apply`` command completes will be automatically found and added to the cluster. We will examine the effects of the following command: .. prompt:: bash # ceph orch apply osd --all-available-devices After running the above command: * If you add new disks to the cluster, they will automatically be used to create new OSDs. * If you remove an OSD and clean the LVM physical volume, a new OSD will be created automatically. If you want to avoid this behavior (disable automatic creation of OSD on available devices), use the ``unmanaged`` parameter: .. prompt:: bash # ceph orch apply osd --all-available-devices --unmanaged=true .. note:: Keep these three facts in mind: - The default behavior of ``ceph orch apply`` causes cephadm constantly to reconcile. This means that cephadm creates OSDs as soon as new drives are detected. - Setting ``unmanaged: True`` disables the creation of OSDs. If ``unmanaged: True`` is set, nothing will happen even if you apply a new OSD service. - ``ceph orch daemon add`` creates OSDs, but does not add an OSD service. * For cephadm, see also :ref:`cephadm-spec-unmanaged`. .. _cephadm-osd-removal: Remove an OSD ============= Removing an OSD from a cluster involves two steps: #. evacuating all placement groups (PGs) from the OSD #. removing the PG-free OSD from the cluster The following command performs these two steps: .. prompt:: bash # ceph orch osd rm [--replace] [--force] Example: .. prompt:: bash # ceph orch osd rm 0 Expected output:: Scheduled OSD(s) for removal OSDs that are not safe to destroy will be rejected. .. note:: After removing OSDs, if the drives the OSDs were deployed on once again become available, cephadm may automatically try to deploy more OSDs on these drives if they match an existing drivegroup spec. If you deployed the OSDs you are removing with a spec and don't want any new OSDs deployed on the drives after removal, it's best to modify the drivegroup spec before removal. Either set ``unmanaged: true`` to stop it from picking up new drives at all, or modify it in some way that it no longer matches the drives used for the OSDs you wish to remove. Then re-apply the spec. For more info on drivegroup specs see :ref:`drivegroups`. For more info on the declarative nature of cephadm in reference to deploying OSDs, see :ref:`cephadm-osd-declarative` Monitoring OSD State -------------------- You can query the state of OSD operation with the following command: .. prompt:: bash # ceph orch osd rm status Expected output:: OSD_ID HOST STATE PG_COUNT REPLACE FORCE STARTED_AT 2 cephadm-dev done, waiting for purge 0 True False 2020-07-17 13:01:43.147684 3 cephadm-dev draining 17 False True 2020-07-17 13:01:45.162158 4 cephadm-dev started 42 False True 2020-07-17 13:01:45.162158 When no PGs are left on the OSD, it will be decommissioned and removed from the cluster. .. note:: After removing an OSD, if you wipe the LVM physical volume in the device used by the removed OSD, a new OSD will be created. For more information on this, read about the ``unmanaged`` parameter in :ref:`cephadm-osd-declarative`. Stopping OSD Removal -------------------- It is possible to stop queued OSD removals by using the following command: .. prompt:: bash # ceph orch osd rm stop Example: .. prompt:: bash # ceph orch osd rm stop 4 Expected output:: Stopped OSD(s) removal This resets the initial state of the OSD and takes it off the removal queue. .. _cephadm-replacing-an-osd: Replacing an OSD ---------------- .. prompt:: bash # ceph orch osd rm --replace [--force] Example: .. prompt:: bash # ceph orch osd rm 4 --replace Expected output:: Scheduled OSD(s) for replacement This follows the same procedure as the procedure in the "Remove OSD" section, with one exception: the OSD is not permanently removed from the CRUSH hierarchy, but is instead assigned a 'destroyed' flag. .. note:: The new OSD that will replace the removed OSD must be created on the same host as the OSD that was removed. **Preserving the OSD ID** The 'destroyed' flag is used to determine which OSD ids will be reused in the next OSD deployment. If you use OSDSpecs for OSD deployment, your newly added disks will be assigned the OSD ids of their replaced counterparts. This assumes that the new disks still match the OSDSpecs. Use the ``--dry-run`` flag to make certain that the ``ceph orch apply osd`` command does what you want it to. The ``--dry-run`` flag shows you what the outcome of the command will be without making the changes you specify. When you are satisfied that the command will do what you want, run the command without the ``--dry-run`` flag. .. tip:: The name of your OSDSpec can be retrieved with the command ``ceph orch ls`` Alternatively, you can use your OSDSpec file: .. prompt:: bash # ceph orch apply -i --dry-run Expected output:: NAME HOST DATA DB WAL node1 /dev/vdb - - When this output reflects your intention, omit the ``--dry-run`` flag to execute the deployment. Erasing Devices (Zapping Devices) --------------------------------- Erase (zap) a device so that it can be reused. ``zap`` calls ``ceph-volume zap`` on the remote host. .. prompt:: bash # ceph orch device zap Example command: .. prompt:: bash # ceph orch device zap my_hostname /dev/sdx .. note:: If the unmanaged flag is unset, cephadm automatically deploys drives that match the OSDSpec. For example, if you use the ``all-available-devices`` option when creating OSDs, when you ``zap`` a device the cephadm orchestrator automatically creates a new OSD in the device. To disable this behavior, see :ref:`cephadm-osd-declarative`. .. _osd_autotune: Automatically tuning OSD memory =============================== OSD daemons will adjust their memory consumption based on the ``osd_memory_target`` config option (several gigabytes, by default). If Ceph is deployed on dedicated nodes that are not sharing memory with other services, cephadm can automatically adjust the per-OSD memory consumption based on the total amount of RAM and the number of deployed OSDs. .. warning:: Cephadm sets ``osd_memory_target_autotune`` to ``true`` by default which is unsuitable for hyperconverged infrastructures. Cephadm will start with a fraction (``mgr/cephadm/autotune_memory_target_ratio``, which defaults to ``.7``) of the total RAM in the system, subtract off any memory consumed by non-autotuned daemons (non-OSDs, for OSDs for which ``osd_memory_target_autotune`` is false), and then divide by the remaining OSDs. The final targets are reflected in the config database with options like:: WHO MASK LEVEL OPTION VALUE osd host:foo basic osd_memory_target 126092301926 osd host:bar basic osd_memory_target 6442450944 Both the limits and the current memory consumed by each daemon are visible from the ``ceph orch ps`` output in the ``MEM LIMIT`` column:: NAME HOST PORTS STATUS REFRESHED AGE MEM USED MEM LIMIT VERSION IMAGE ID CONTAINER ID osd.1 dael running (3h) 10s ago 3h 72857k 117.4G 17.0.0-3781-gafaed750 7015fda3cd67 9e183363d39c osd.2 dael running (81m) 10s ago 81m 63989k 117.4G 17.0.0-3781-gafaed750 7015fda3cd67 1f0cc479b051 osd.3 dael running (62m) 10s ago 62m 64071k 117.4G 17.0.0-3781-gafaed750 7015fda3cd67 ac5537492f27 To exclude an OSD from memory autotuning, disable the autotune option for that OSD and also set a specific memory target. For example, .. prompt:: bash # ceph config set osd.123 osd_memory_target_autotune false ceph config set osd.123 osd_memory_target 16G .. _drivegroups: Advanced OSD Service Specifications =================================== :ref:`orchestrator-cli-service-spec`\s of type ``osd`` are a way to describe a cluster layout, using the properties of disks. Service specifications give the user an abstract way to tell Ceph which disks should turn into OSDs with which configurations, without knowing the specifics of device names and paths. Service specifications make it possible to define a yaml or json file that can be used to reduce the amount of manual work involved in creating OSDs. For example, instead of running the following command: .. prompt:: bash [monitor.1]# ceph orch daemon add osd **:** for each device and each host, we can define a yaml or json file that allows us to describe the layout. Here's the most basic example. Create a file called (for example) ``osd_spec.yml``: .. code-block:: yaml service_type: osd service_id: default_drive_group # custom name of the osd spec placement: host_pattern: '*' # which hosts to target spec: data_devices: # the type of devices you are applying specs to all: true # a filter, check below for a full list This means : #. Turn any available device (ceph-volume decides what 'available' is) into an OSD on all hosts that match the glob pattern '*'. (The glob pattern matches against the registered hosts from `host ls`) A more detailed section on host_pattern is available below. #. Then pass it to `osd create` like this: .. prompt:: bash [monitor.1]# ceph orch apply -i /path/to/osd_spec.yml This instruction will be issued to all the matching hosts, and will deploy these OSDs. Setups more complex than the one specified by the ``all`` filter are possible. See :ref:`osd_filters` for details. A ``--dry-run`` flag can be passed to the ``apply osd`` command to display a synopsis of the proposed layout. Example .. prompt:: bash [monitor.1]# ceph orch apply -i /path/to/osd_spec.yml --dry-run .. _osd_filters: Filters ------- .. note:: Filters are applied using an `AND` gate by default. This means that a drive must fulfill all filter criteria in order to get selected. This behavior can be adjusted by setting ``filter_logic: OR`` in the OSD specification. Filters are used to assign disks to groups, using their attributes to group them. The attributes are based off of ceph-volume's disk query. You can retrieve information about the attributes with this command: .. code-block:: bash ceph-volume inventory Vendor or Model ^^^^^^^^^^^^^^^ Specific disks can be targeted by vendor or model: .. code-block:: yaml model: disk_model_name or .. code-block:: yaml vendor: disk_vendor_name Size ^^^^ Specific disks can be targeted by `Size`: .. code-block:: yaml size: size_spec Size specs __________ Size specifications can be of the following forms: * LOW:HIGH * :HIGH * LOW: * EXACT Concrete examples: To include disks of an exact size .. code-block:: yaml size: '10G' To include disks within a given range of size: .. code-block:: yaml size: '10G:40G' To include disks that are less than or equal to 10G in size: .. code-block:: yaml size: ':10G' To include disks equal to or greater than 40G in size: .. code-block:: yaml size: '40G:' Sizes don't have to be specified exclusively in Gigabytes(G). Other units of size are supported: Megabyte(M), Gigabyte(G) and Terabyte(T). Appending the (B) for byte is also supported: ``MB``, ``GB``, ``TB``. Rotational ^^^^^^^^^^ This operates on the 'rotational' attribute of the disk. .. code-block:: yaml rotational: 0 | 1 `1` to match all disks that are rotational `0` to match all disks that are non-rotational (SSD, NVME etc) All ^^^ This will take all disks that are 'available' .. note:: This is exclusive for the data_devices section. .. code-block:: yaml all: true Limiter ^^^^^^^ If you have specified some valid filters but want to limit the number of disks that they match, use the ``limit`` directive: .. code-block:: yaml limit: 2 For example, if you used `vendor` to match all disks that are from `VendorA` but want to use only the first two, you could use `limit`: .. code-block:: yaml data_devices: vendor: VendorA limit: 2 .. note:: `limit` is a last resort and shouldn't be used if it can be avoided. Additional Options ------------------ There are multiple optional settings you can use to change the way OSDs are deployed. You can add these options to the base level of an OSD spec for it to take effect. This example would deploy all OSDs with encryption enabled. .. code-block:: yaml service_type: osd service_id: example_osd_spec placement: host_pattern: '*' spec: data_devices: all: true encrypted: true See a full list in the DriveGroupSpecs .. py:currentmodule:: ceph.deployment.drive_group .. autoclass:: DriveGroupSpec :members: :exclude-members: from_json Examples ======== The simple case --------------- All nodes with the same setup .. code-block:: none 20 HDDs Vendor: VendorA Model: HDD-123-foo Size: 4TB 2 SSDs Vendor: VendorB Model: MC-55-44-ZX Size: 512GB This is a common setup and can be described quite easily: .. code-block:: yaml service_type: osd service_id: osd_spec_default placement: host_pattern: '*' spec: data_devices: model: HDD-123-foo # Note, HDD-123 would also be valid db_devices: model: MC-55-44-XZ # Same here, MC-55-44 is valid However, we can improve it by reducing the filters on core properties of the drives: .. code-block:: yaml service_type: osd service_id: osd_spec_default placement: host_pattern: '*' spec: data_devices: rotational: 1 db_devices: rotational: 0 Now, we enforce all rotating devices to be declared as 'data devices' and all non-rotating devices will be used as shared_devices (wal, db) If you know that drives with more than 2TB will always be the slower data devices, you can also filter by size: .. code-block:: yaml service_type: osd service_id: osd_spec_default placement: host_pattern: '*' spec: data_devices: size: '2TB:' db_devices: size: ':2TB' .. note:: All of the above OSD specs are equally valid. Which of those you want to use depends on taste and on how much you expect your node layout to change. Multiple OSD specs for a single host ------------------------------------ Here we have two distinct setups .. code-block:: none 20 HDDs Vendor: VendorA Model: HDD-123-foo Size: 4TB 12 SSDs Vendor: VendorB Model: MC-55-44-ZX Size: 512GB 2 NVMEs Vendor: VendorC Model: NVME-QQQQ-987 Size: 256GB * 20 HDDs should share 2 SSDs * 10 SSDs should share 2 NVMes This can be described with two layouts. .. code-block:: yaml service_type: osd service_id: osd_spec_hdd placement: host_pattern: '*' spec: data_devices: rotational: 1 db_devices: model: MC-55-44-XZ limit: 2 # db_slots is actually to be favoured here, but it's not implemented yet --- service_type: osd service_id: osd_spec_ssd placement: host_pattern: '*' spec: data_devices: model: MC-55-44-XZ db_devices: vendor: VendorC This would create the desired layout by using all HDDs as data_devices with two SSD assigned as dedicated db/wal devices. The remaining SSDs(10) will be data_devices that have the 'VendorC' NVMEs assigned as dedicated db/wal devices. Multiple hosts with the same disk layout ---------------------------------------- Assuming the cluster has different kinds of hosts each with similar disk layout, it is recommended to apply different OSD specs matching only one set of hosts. Typically you will have a spec for multiple hosts with the same layout. The service id as the unique key: In case a new OSD spec with an already applied service id is applied, the existing OSD spec will be superseded. cephadm will now create new OSD daemons based on the new spec definition. Existing OSD daemons will not be affected. See :ref:`cephadm-osd-declarative`. Node1-5 .. code-block:: none 20 HDDs Vendor: VendorA Model: SSD-123-foo Size: 4TB 2 SSDs Vendor: VendorB Model: MC-55-44-ZX Size: 512GB Node6-10 .. code-block:: none 5 NVMEs Vendor: VendorA Model: SSD-123-foo Size: 4TB 20 SSDs Vendor: VendorB Model: MC-55-44-ZX Size: 512GB You can use the 'placement' key in the layout to target certain nodes. .. code-block:: yaml service_type: osd service_id: disk_layout_a placement: label: disk_layout_a spec: data_devices: rotational: 1 db_devices: rotational: 0 --- service_type: osd service_id: disk_layout_b placement: label: disk_layout_b spec: data_devices: model: MC-55-44-XZ db_devices: model: SSD-123-foo This applies different OSD specs to different hosts depending on the `placement` key. See :ref:`orchestrator-cli-placement-spec` .. note:: Assuming each host has a unique disk layout, each OSD spec needs to have a different service id Dedicated wal + db ------------------ All previous cases co-located the WALs with the DBs. It's however possible to deploy the WAL on a dedicated device as well, if it makes sense. .. code-block:: none 20 HDDs Vendor: VendorA Model: SSD-123-foo Size: 4TB 2 SSDs Vendor: VendorB Model: MC-55-44-ZX Size: 512GB 2 NVMEs Vendor: VendorC Model: NVME-QQQQ-987 Size: 256GB The OSD spec for this case would look like the following (using the `model` filter): .. code-block:: yaml service_type: osd service_id: osd_spec_default placement: host_pattern: '*' spec: data_devices: model: MC-55-44-XZ db_devices: model: SSD-123-foo wal_devices: model: NVME-QQQQ-987 It is also possible to specify directly device paths in specific hosts like the following: .. code-block:: yaml service_type: osd service_id: osd_using_paths placement: hosts: - Node01 - Node02 spec: data_devices: paths: - /dev/sdb db_devices: paths: - /dev/sdc wal_devices: paths: - /dev/sdd This can easily be done with other filters, like `size` or `vendor` as well. It's possible to specify the `crush_device_class` parameter within the DriveGroup spec, and it's applied to all the devices defined by the `paths` keyword: .. code-block:: yaml service_type: osd service_id: osd_using_paths placement: hosts: - Node01 - Node02 crush_device_class: ssd spec: data_devices: paths: - /dev/sdb - /dev/sdc db_devices: paths: - /dev/sdd wal_devices: paths: - /dev/sde The `crush_device_class` parameter, however, can be defined for each OSD passed using the `paths` keyword with the following syntax: .. code-block:: yaml service_type: osd service_id: osd_using_paths placement: hosts: - Node01 - Node02 crush_device_class: ssd spec: data_devices: paths: - path: /dev/sdb crush_device_class: ssd - path: /dev/sdc crush_device_class: nvme db_devices: paths: - /dev/sdd wal_devices: paths: - /dev/sde .. _cephadm-osd-activate: Activate existing OSDs ====================== In case the OS of a host was reinstalled, existing OSDs need to be activated again. For this use case, cephadm provides a wrapper for :ref:`ceph-volume-lvm-activate` that activates all existing OSDs on a host. .. prompt:: bash # ceph cephadm osd activate ... This will scan all existing disks for OSDs and deploy corresponding daemons. Further Reading =============== * :ref:`ceph-volume` * :ref:`rados-index`