NFS Volume Provider (part I)-Play 5 minutes per day OpenStack (62)

Cinder-volume supports a variety of volume provider, we have been using the default LVM in the previous section, we will increase the NFS volume provider.

Although NFS is more applied in experimental or small-scale cinder environments, it is unlikely to be used in production environments due to performance and lack of high availability, but the significance of learning NFS volume provider is:
1. Understand how Cinder-volume supports multiple backend
2. More importantly, you can understand how cinder-volume,nova-compute and volume provider work together to provide block storage for instance.
3. Extrapolate, can quickly understand and access to other production-grade backend, such as Ceph, commercial storage and so on.

Shows how cinder and Nova work in coordination with the NFS volume provider.

NFS Volume Provider
That's what we usually call NFS Server, which provides remote NFS directories, NFS Clinet can mount these remote directories locally, and then create, read and write files and subdirectories like a local directory.

Cinder-volume
Storage nodes Manage volume in NFS Volume provider through NFS driver, which are actually files in NFS.

Nova-compute
The compute node mounts the NFS volume provider directory volume to local, and then maps the volume file as a virtual hard disk to instance.

Here are a few things to emphasize:

2. In Cinder's driver architecture, storage nodes and volume Provider that run Cinder-volume can be completely independent of two entities. Cinder-volume communicates, controls and manages volume through driver and volume Provider.

4. Instance Read and write volume, the data stream does not need to go through the storage node, but directly read and write to volume in volume Provider. As shown, the connection between the storage node and the NFS Volume Provider is used only for the management and control of the Volume (green connection); Real data reads and writes are done through the connection between the compute node and the NFS Volume Proiver (Purple Line). This design reduces the intermediate link, the storage node does not directly participate in the data transmission, guarantees the reading and writing efficiency.

6. Other Volume Provider (such as Ceph,swift, commercial storage, etc.) follow the design of this control flow and data flow separation.

Configuring NFS Volume Provider

In the experimental environment, the NFS Remote Directory for NFS volume provider is/nfs_storage on Mount point on the 192.168.104.11:/storagecinder-volume service node.

Add the NFS backend in the/etc/cinder/cinder.conf.

1. enabled_backends = Lvmdriver-1,nfs Let Cinder-volume use NFS backend

2. [nfs "in detail configuring NFS backend. Includes: a) specifies mount point/nfs_storage on the storage node as NFS.

Nfs_mount_point_base =/nfs_storage

b) View the list of/etc/cinder/nfs_shares active NFS shared directories. Nfs_shares_config =/etc/cinder/nfs_shares, the contents of which are

Only 192.168.104.11:/storage in the list. If you want multiple NFS shared directories to hold volume, you can add them to the file.

c) NFS Volume driver.

Volume_driver=cinder.volume.drivers.nfs.nfsdriver

d) Set volume backend name. It is important to create the corresponding volume type in cinder based on the volume_backend_name here. Volume_backend_name = NFS

Restart Cinder-volume,cinder Service-list confirm that the NFS Cinder-volume service is working correctly.

Create the NFS volume type.

Open the GUI page, Volume Types, Volumes, System, admin, click "Create Volume Type".

Name NFS, click "Create Volume Type".

Select NFS Volume TYEP, click the drop-down menu "View Extra Specs"

Click "Create", Key input volume_backend_name; Value input NFS.

NFS Volume provider is ready, the next section we will create volume for NFS backend.

NFS Volume Provider (part I)-Play 5 minutes per day OpenStack (62)