Openstack: Does cinder driver allow in-use volumes to be extended?

Applies to

• OpenStack Cinder
• NetAppDriver
• SolidFireDriver

Answer

NetAppDriver (ONTAP)

• In-use volume extension is not supported by the NetAppDriver cinder driver.
• Currently, it is not possible to extend the size of a root volume that is attached to a server and uses a NetApp ONTAP backend.
• The extension can only be done by detaching a non-root volume from the server. 
• When attempting to extend a root volume, the following event is seen in Cinder scheduler.log:

/var/log/cinder/scheduler.log:2023-01-05 10:46:12.116 8985 DEBUG cinder.scheduler.filters.capabilities_filter [req-598b1f1c-f1b6-42c6-b481-d9491f36f88a 9f61737278e74e299ecf78393c6f2cc4 aa13b5b8c1e449fd93e598af2b4af8d0 - default default] Backend doesn't support attached volume extend _satisfies_extra_specs /usr/lib/python2.7/site-packages/cinder/scheduler/filters/capabilities_filter.py:45

SolidFireDriver

• It is possible to extend a in-use root volume by toggling the volume to 'available'.  The procedure for doing so is:

1. Power down VM

# openstack server stop extend_vm

# openstack server list
+--------------------------------------+-----------------+---------+----------------------+-------+----------+
| ID                                   | Name            | Status  | Networks             | Image | Flavor   |
+--------------------------------------+-----------------+---------+----------------------+-------+----------+
| ad0af6b4-9d24-4195-8095-6603b0426044 | extend_vm       | SHUTOFF | intnet=192.168.0.70  |       | m1.small |

# openstack volume list
+--------------------------------------+------------------+-----------+------+------------------------------------------+
| ID                                   | Name             | Status    | Size | Attached to                              |
+--------------------------------------+------------------+-----------+------+------------------------------------------+
| e1ec70e4-eb4e-425c-a141-38c00aa6df9e | solidfire_extend | in-use    |    2 |                                          |

2. Reset the cinder volume state to 'available':

# cinder reset-state --state available e1ec70e4-eb4e-425c-a141-38c00aa6df9e

3. Resize the volume:

        # openstack volume set e1ec70e4-eb4e-425c-a141-38c00aa6df9e --size 4

# openstack volume show e1ec70e4-eb4e-425c-a141-38c00aa6df9e | grep size
| size                           | 4         

Note that after the volume resize, the status should return to in-use:

# openstack volume show e1ec70e4-eb4e-425c-a141-38c00aa6df9e | grep status
| migration_status               | None  |
| os-vol-mig-status-attr:migstat | None  |
| os-vol-mig-status-attr:name_id | None  |
| replication_status             | None  |
| status                         | in-use

4. Power VM on

# openstack server start extend_vm

]# openstack server list
+--------------------------------------+-----------------+---------+----------------------+-------+----------+
| ID                                   | Name            | Status  | Networks             | Image | Flavor   |
+--------------------------------------+-----------------+---------+----------------------+-------+----------+
| ad0af6b4-9d24-4195-8095-6603b0426044 | extend_vm       | ACTIVE  | intnet=192.168.0.70  |       | m1.small |

 

Additional Information

Refer to this article:

Redhat has a solution for this issue documented in "How to extend attached/in-use volume in Openstack? "

Extract (edited):

You can use the cinder client when mentioning a microversion equal or greater than 3.42 to ensure volume extend works:
# cinder  --os-volume-api-version <Microversion> extend  <volume_id>  <new_size_in_GiB>

Example:
# cinder  --os-volume-api-version 3.42 extend  582a5eb4-0bfc-460b-a32e-d051a9a72d2a  10

Note: openstack unified client does not yet support cinder microversion hence it can not be used.