Manila Network Plugins¶

What is a network plugin in Manila?¶

A network plugin is a python class that uses a specific facility (e.g. Neutron or Nova network) to provide network resources to the manila-share service.

When to use a network plugin?¶

A Manila share driver may be configured in one of two modes, where it is managing the lifecycle of share servers on its own or where it is merely providing storage resources on a pre-configured share server. This mode is defined using the boolean option driver_handles_share_servers in the Manila configuration file. A network plugin is only useful when a driver is handling its own share servers.

When driver_handles_share_servers is set to True, a share driver will be called to create share servers for shares using information provided within a share network. This information will be provided to one of the enabled network plugins that will handle reservation, creation and deletion of network resources including IP addresses and network interfaces.

As an exception, any share drivers that use Nova for the creation of share servers should use some wrapper for network plugins, because Nova handles the creation of network resources for its VMs. In the Manila Kilo version, only the Generic driver uses Nova with the help of its own network helpers, which serve the same needs but are related only to this share driver.

What network plugins are available?¶

There are three different network plugins and five python classes in Manila:

1 Network plugin for using the OpenStack networking project Neutron.

It allows one to use any network segmentation that Neutron supports. It is up to each share driver to support at least one network segmentation type.

1.1 manila.network.neutron.neutron_network_plugin.NeutronNetworkPlugin.

This is the default network plugin. It requires that neutron_net_id and neutron_subnet_id are provided when defining the share network that will be used for the creation of share servers. The user may define any number of share networks corresponding to the various physical network segments in a tenant environment.

1.2 manila.network.neutron.neutron_network_plugin.NeutronSingleNetworkPlugin.

This is a simplification of the previous case. It accepts values for neutron_net_id and neutron_subnet_id from the Manila configuration file and uses one network for all shares.

1.3 manila.network.neutron.neutron_network_plugin.NeutronBindNetworkPlugin.

This driver waits for active binding and fails if a Neutron port can’t be bound or an error occurs. This plugin is useful for agent based binding (like OVS with docker driver) and fabric binding where real HW reconfiguration is taking place. The existing NeutronBindSingleNetworkPlugin is a combination of 1.2 and 1.3.

When only a single network is needed, the NeutronSingleNetworkPlugin (1.2) is a simple solution. Otherwise NeutronNetworkPlugin (1.1) should be chosen.

2 Network plugin for working with OpenStack native networking from Nova.

It supports either flat networks or VLAN-segmented networks.

2.1 manila.network.nova_network_plugin.NovaNetworkPlugin.

This plugin serves the networking needs when Nova networking is configured in the cloud instead of Neutron. It requires a single parameter, nova_net_id.

2.2 manila.network.nova_network_plugin.NovaSingleNetworkPlugin.

This one works in the same way as the previous one with one difference. It takes nova_net_id from the Manila configuration file and creates share servers using only one network.

When only a single network is needed, the NovaSingleNetworkPlugin (2.2) is a simple solution. Otherwise NovaNetworkPlugin (1.1) should be chosen.

3 Network plugin for specifying networks independently from OpenStack

networking services.

3.1 manila.network.standalone_network_plugin.StandaloneNetworkPlugin.

This plug-in uses a pre-existing network that is available to the manila-share host. This network may be handled either by OpenStack or be created independently by any other means. The plugin supports any type of network - flat and segmented. As above, it is completely up to the driver to support the network type for which the network plugin is configured.

Approaches for setup of network plugins¶

Each manila-share service may have its own network plugin or one that is shared with other services. All configuration options for network plugins may be set in three ways by priorities:

• Using a separate configuration group.

  For this case, the config opt network_config_group should be defined in the config group of the manila-share service and have the name of the config group with the defined options for the network plugin. First priority.

• Using config group of manila-share service. Second priority.
• Using config group [DEFAULT]. Lowest priority.

A specific network plugin is enabled by setting the configuration option network_api_class to one of the values defined in the previous section What network plugins are available?. This option can be defined in any of the approaches above along with options for the network plugin itself.

Example of network plugin configuration¶

Let’s configure three manila-share services that use different approaches for configuration of network plugins. As noted in section What network plugins are available?, in the Kilo version of OpenStack there are 5 (five) network plugins, three of which require configuration options - 1.2, 2.2 and 3.1. We will use a configuration example using network plugin 1.2, the NeutronSingleNetworkPlugin.

Here is the configuration:

[DEFAULT]
enabled_share_backends = SHARE_BACKEND_1,SHARE_BACKEND_2,SHARE_BACKEND_3
network_api_class = manila.network.neutron.neutron_network_plugin.NeutronSingleNetworkPlugin
neutron_net_id = neutron_net_id_DEFAULT
neutron_subnet_id = neutron_subnet_id_DEFAULT

[NETWORK_PLUGIN]
neutron_net_id = neutron_net_id_NETWORK_PLUGIN
neutron_subnet_id = neutron_subnet_id_NETWORK_PLUGIN

[SHARE_BACKEND_1]
# This share backend is enabled for handling of share servers using opts
# for network plugin defined in separate config group called `NETWORK_PLUGIN`.
network_config_group = NETWORK_PLUGIN
driver_handles_share_servers = True

[SHARE_BACKEND_2]
# This share backend is enabled for handling of share servers using opts
# defined in its own config group.
driver_handles_share_servers = True
neutron_net_id = neutron_net_id_SHARE_BACKEND_2
neutron_subnet_id = neutron_subnet_id_SHARE_BACKEND_2

[SHARE_BACKEND_3]
# This share backend is enabled for handling of share servers using opts
# defined in config group [DEFAULT].
driver_handles_share_servers = True

Here is a list of neutron_net_id and neutron_subnet_id values for our manila-share services:

• [SHARE_BACKEND_1]

  • neutron_net_id=neutron_net_id_NETWORK_PLUGIN
  • neutron_subnet_id=neutron_subnet_id_NETWORK_PLUGIN

• [SHARE_BACKEND_2]

  • neutron_net_id=neutron_net_idSHARE_BACKEND_2
  • neutron_subnet_id=neutron_subnet_id_SHARE_BACKEND_2

• [SHARE_BACKEND_3]

  • neutron_net_id=neutron_net_id_DEFAULT
  • neutron_subnet_id=neutron_subnet_id_DEFAULT

The value for option network_api_class was taken by each manila-share service from group [DEFAULT] because it was not redefined in other places.