Pure Storage volume driver

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Limitations and known issues
Supported operations
Configure OpenStack and Purity

The Pure Storage FlashArray volume driver for OpenStack Block Storage interacts with configured Pure Storage arrays and supports various operations.

This driver can be configured in OpenStack Block Storage to work with the iSCSI storage protocol.

This driver is compatible with Purity FlashArrays that support the REST API (Purity 3.4.0 and newer) and that are capable of iSCSI connectivity. This release supports installation with OpenStack clusters running the Juno version that use the KVM or QEMU hypervisors together with OpenStack Compute service's libvirt driver.

Limitations and known issues

If you do not set up the nodes hosting instances to use multipathing, all iSCSI connectivity will use a single physical 10-gigabit Ethernet port on the array. In addition to significantly limiting the available bandwidth, this means you do not have the high-availability and non-disruptive upgrade benefits provided by FlashArray.

Workaround: You must set up multipathing on your hosts.

In the default configuration, OpenStack Block Storage does not provision volumes on a backend whose available raw space is less than the logical size of the new volume. Due to Purity's data reduction technology, such a volume could actually fit in the backend, and thus OpenStack Block Storage default configuration does not take advantage of all available space.

Workaround: Turn off the CapacityFilter.

Supported operations

Create, delete, attach, detach, clone and extend volumes.
Create a volume from snapshot.
Create and delete volume snapshots.

Configure OpenStack and Purity

You need to configure both your Purity array and your OpenStack cluster.

	Note
	These instructions assume that the `cinder-api` and `cinder-scheduler` services are installed and configured in your OpenStack cluster.

Configure the OpenStack Block Storage service
In these steps, you will edit the cinder.conf file to configure OpenStack Block Storage service to enable multipathing and to use the Pure Storage FlashArray as back-end storage.
1. Retrieve an API token from Purity
  The OpenStack Block Storage service configuration requires an API token from Purity. Actions performed by the volume driver use this token for authorization. Also, Purity logs the volume driver's actions as being performed by the user who owns this API token.
  If you created a Purity user account that is dedicated to managing your OpenStack Block Storage volumes, copy the API token from that user account.
  Use the appropriate create or list command below to display and copy the Purity API token:
  - To create a new API token:
```
$ pureadmin create --api-token USER
```
    The following is an example output:
```
$ pureadmin create --api-token pureuser
Name      API Token                             Created
pureuser  902fdca3-7e3f-d2e4-d6a6-24c2285fe1d9  2014-08-04 14:50:30
```
  - To list an existing API token:
```
$ pureadmin list --api-token --expose USER
```
    The following is an example output:
```
$ pureadmin list --api-token --expose pureuser
Name      API Token                             Created
pureuser  902fdca3-7e3f-d2e4-d6a6-24c2285fe1d9  2014-08-04 14:50:30
```
2. Copy the API token retrieved (902fdca3-7e3f-d2e4-d6a6-24c2285fe1d9 from the examples above) to use in the next step.
3. Edit the OpenStack Block Storage service configuration file
  The following sample /etc/cinder/cinder.conf configuration lists the relevant settings for a typical Block Storage service using a single Pure Storage array:
```
[DEFAULT]
....
enabled_backends = puredriver-1
default_volume_type = puredriver-1
....

[puredriver-1]
volume_backend_name = puredriver-1
volume_driver = cinder.volume.drivers.pure.PureISCSIDriver
san_ip = IP_PURE_MGMT
pure_api_token = PURE_API_TOKEN
use_multipath_for_image_xfer = True
```
  Replace the following variables accordingly:
  IP_PURE_MGMT
  The IP address of the Pure Storage array's management interface or a domain name that resolves to that IP address.
  PURE_API_TOKEN
  The Purity Authorization token that the volume driver uses to perform volume management on the Pure Storage array.
Create Purity host objects
Before using the volume driver, follow these steps to create a host in Purity for each OpenStack iSCSI initiator IQN that will connect to the FlashArray.
For every node that the driver runs on and every compute node that will connect to the FlashArray:
1. check the file /etc/iscsi/initiatorname.iscsi.
  For each IQN in that file:
  1. copy the IQN string and run the following command to create a Purity host for an IQN:
```
$ purehost create --iqnlist IQN HOST
```
    Replace the following variables accordingly:
    IQN
    The IQN retrieved from the /etc/iscsi/initiatorname.iscsi file
    HOST
    An unique friendly name for this entry.
    Note
    Do not specify multiple IQNs with the --iqnlist option. Each FlashArray host must be configured to a single OpenStack IQN.

Questions? Discuss on ask.openstack.org
Found an error? Report a bug against this page

Legal notices

	Note
	Do not specify multiple IQNs with the `--iqnlist` option. Each FlashArray host must be configured to a single OpenStack IQN.