Configure OpenStack for use with the StorPool Cinder backend

Cinder backend

An OpenStack environment that uses StorPool as a storage backend only needs the client services; the actual disks that store the data may be on a separate storage cluster.

This section describes the configuration of the OpenStack Cinder (block storage) service. Note that the StorPool Cinder drivers may need to be installed beforehand; see the "Installing the StorPool drivers" section for details.

Configuring the StorPool Cinder backend

Once the StorPool Cinder volume driver is installed (as part of OpenStack or, for earlier releases, separately), a driver backend section must be created in the /etc/cinder/cinder.conf file:

[storpool]
volume_driver=cinder.volume.drivers.storpool.StorPoolDriver
storpool_template=hybrid-r3
report_discard_supported=True

If StorPool should be the only storage backend, all the enabled_backends and volume_backend lines should be removed from the cinder.conf file's [DEFAULT] section and a single line should be added:

enabled_backends=storpool

If other volume backends should coexist with StorPool, make sure that storpool is listed in an enabled_backends setting.

Then restart the relevant Cinder services:

# service cinder-volume restart
# service cinder-scheduler restart

Using StorPool templates via Cinder volume types

If a StorPool cluster has several different templates defined (for reasons ranging from quality of service to fault sets and availability zones), they may be exposed to Cinder through the use of volume types. For each StorPool template, define a volume type and specify the StorPool template name as its storpool_template property:

# openstack volume type create --property volume_backend_name=storpool --property storpool_template='hybrid-r2' hybrid-r2
# openstack volume type create --property volume_backend_name=storpool --property storpool_template='hdd-only' hdd-only

The names of the available StorPool templates may be viewed with the storpool template list command if the StorPool CLI is installed.

Creating volumes and snapshots

To create a new, blank volume in one of the previously defined volume types:

# openstack volume create --type hybrid --size 10 test-volume

To make sure that there is actually a StorPool volume created, first obtain the OpenStack internal volume identifier:

# openstack volume show -f value -c id test-volume
cc2b3692-a2b6-4ad7-82ef-6a37d3e0f4da

# storpool volume list | fgrep -e 'cc2b3692-a2b6-4ad7-82ef-6a37d3e0f4da'
| os--volume-cc2b3692-a2b6-4ad7-82ef-6a37d3e0f4da |   10 GB |     3 | hdd        | hdd        | ssd        |

To create a volume from an existing image stored in Glance:

# openstack volume create --type hybrid --size 1 --image cirros-0.4.0 cirros-v

To create a snapshot of this volume:

# openstack volume snapshot create --name cirros cirros-v

Nova attachment driver

This section describes the configuration of the OpenStack Nova (compute) service to use StorPool-backed volumes created by Cinder.

The changes needed to let Nova recognize StorPool volumes as exported by Cinder were merged into the OpenStack Queens (February 2018) release.

Using StorPool volumes as instance root disks

The preferred way to use StorPool volumes as root disks for Nova instances is to create a volume-backed instance and a new volume for it to use.

Choose a Glance image to use as the root disk.
Create a Cinder volume from that Glance image.
Create a snapshot of that Cinder volume.
Create a Nova instance and tell it to create a new volume from the snapshot.

Step 4 may be repeated for many instances; a new volume shall be created for each instance's root disk, but within the StorPool cluster all these volumes will be descended from the one holding the Cinder snapshot, so there shall be no needless copying of data and no overuse of disk space.

Installing the StorPool drivers

Most of the time, the StorPool Cinder driver in the OpenStack Git repository or the released versions is not completely up-to-date with the latest features and bugfixes.

Preliminary setup

Set up an OpenStack cluster.
Set up a StorPool cluster.
Set up at least the StorPool client (the storpool_beacon and storpool_block services) on the OpenStack controller node and on each of the hypervisor nodes.

On the node that will run the cinder-volume service and all the hypervisor nodes that will run the nova-compute service, install the storpool and storpool-spopenstack Python packages:

# Install pip (the Python package installer) first
yum install python-pip
# ...or...
apt-get install --no-install-recommends python-pip

pip install storpool
pip install storpool.spopenstack

On the same nodes, clone the StorPool OpenStack Integration Git repository or copy it from some other host where it has been cloned:
```
# Clone the StorPool OpenStack Integration repository
git clone https://github.com/storpool/storpool-openstack-integration.git
```

Set up the Cinder volume backend

Change into the storpool-openstack-integration/ directory prepared in the last step of the "Preliminary setup" section above.
Let the StorPool OpenStack integration suite find your Cinder drivers and apply the StorPool integration changes: and make the necessary modifications in its own work directory:
```
./sp-openstack check
./sp-openstack install cinder os_brick
```
Proceed as per the "Configuring the OpenStack Cinder StorPool volume backend" section above.

Set up the Nova volume attachment driver (on each hypevisor node)

Change into the storpool-openstack-integration/ directory prepared in the last step of the "Preliminary setup" section above.
Make sure that the Python modules storpool and storpool.spopenstack have also been installed on all the hypervisor nodes (see the "Preliminary setup" section above).
Let the StorPool OpenStack integration suite find your Nova drivers and make the necessary modifications in its own work directory:
```
./sp-openstack check
./sp-openstack install nova
```
Proceed as per the "Configuring the OpenStack Nova StorPool volume attachment driver" section above.