Merge "Add documentation page for basic volume quality of service"

doc/source/admin/blockstorage-basic-volume-qos.rst

@@ -0,0 +1,80 @@
+===============================
+Basic volume quality of service
+===============================
+
+Basic volume QoS allows you to define hard performance limits for volumes
+on a per-volume basis.
+
+Performance parameters for attached volumes are controlled using volume types
+and associated extra-specs.
+
+As of the 13.0.0 Rocky release, Cinder supports the following options to
+control volume quality of service, the values of which should be fairly
+self-explanatory:
+
+* `read_iops_sec`
+* `write_iops_sec`
+* `total_iops_sec`
+* `read_bytes_sec`
+* `write_bytes_sec`
+* `total_bytes_sec`
+* `read_iops_sec_max`
+* `write_iops_sec_max`
+* `total_iops_sec_max`
+* `read_bytes_sec_max`
+* `write_bytes_sec_max`
+* `total_bytes_sec_max`
+* `size_iops_sec`
+
+Note that the `total_*` and `total_*_max` options for both iops and bytes
+cannot be used with the equivalent `read` and `write` values.
+
+For example, in order to create a QoS extra-spec with 20000 read IOPs and
+10000 write IOPs, you might use the Cinder client in the following way:
+
+.. code-block:: console
+
+   $ cinder qos-create high-iops consumer="front-end" \
+     read_iops_sec=20000 write_iops_sec=10000
+   +----------+--------------------------------------+
+   | Property | Value                                |
+   +----------+--------------------------------------+
+   | consumer | front-end                            |
+   | id       | f448f61c-4238-4eef-a93a-2024253b8f75 |
+   | name     | high-iops                            |
+   | specs    | read_iops_sec : 20000                |
+   |          | write_iops_sec : 10000               |
+   +----------+--------------------------------------+
+
+The equivalent OpenStack client command would be:
+
+
+.. code-block:: console
+
+   $ openstack volume qos create --consumer "front-end" \
+     --property "read_iops_sec=20000" \
+     --property "write_iops_sec=10000" \
+     high-iops
+
+Once this is done, you can associate this QoS with a volume type by using
+the `qos-associate` Cinder client command.
+
+.. code-block:: console
+
+   $ cinder qos-associate QOS_ID VOLUME_TYPE_ID
+
+or using the `openstack volume qos associate` OpenStack client command.
+
+.. code-block:: console
+
+   $ openstack volume qos associate QOS_ID VOLUME_TYPE_ID
+
+You can now create a new volume and attempt to attach it to a consumer such
+as Nova.  If you login to the Nova compute host, you'll be able to see the
+assigned limits when checking the XML definition of the virtual machine
+with `virsh dumpxml`.
+
+.. note::
+
+   As of the Nova 18.0.0 Rocky release, front end QoS settings are only
+   supported when using the libvirt driver.

doc/source/admin/index.rst

@@ -31,6 +31,7 @@ Amazon EC2 Elastic Block Storage (EBS) offering.
    generalized_filters.rst
    blockstorage-backup-disks.rst
    blockstorage-boot-from-volume.rst
+   blockstorage-basic-volume-qos.rst
    blockstorage-capacity-based-qos.rst
    blockstorage-consistency-groups.rst
    blockstorage-driver-filter-weighing.rst