Add doc for network plugins
Add doc with description of network plugins and examples of their usage. Change-Id: Ibda70b99219325893c408ab06d2c670f0d422169
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vponomaryov
Clinton Knight
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@ -20,3 +20,4 @@ Admin Reference
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intro
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quick_start
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multi_backends
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network_plugins
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198
doc/source/adminref/network_plugins.rst
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198
doc/source/adminref/network_plugins.rst
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..
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Licensed under the Apache License, Version 2.0 (the "License"); you may
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not use this file except in compliance with the License. You may obtain
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a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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License for the specific language governing permissions and limitations
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under the License.
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Manila Network Plugins
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======================
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The Manila architecture defines an abstraction layer for network resource
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provisioning, and it provides a number of concrete `network plugins`,
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allowing administrators to choose from a variety of options for how network
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resources are assigned to their tenants' networked storage. This document
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describes how network plugins may be configured and used in Manila.
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What is a network plugin in Manila?
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-----------------------------------
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A network plugin is a python class that uses a specific facility (e.g.
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Neutron or Nova network) to provide network resources to the
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:term:`manila-share` service.
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When to use a network plugin?
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-----------------------------
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A Manila `share driver` may be configured in one of two modes, where it is
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managing the lifecycle of `share servers` on its own or where it is merely
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providing storage resources on a pre-configured share server. This mode
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is defined using the boolean option `driver_handles_share_servers` in the
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Manila configuration file. A network plugin is only useful when a driver is
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handling its own share servers.
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.. note::
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Not all share drivers support both modes. Each driver must report which
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mode(s) it supports to the manila-share service.
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When `driver_handles_share_servers` is set to `True`, a share driver will be
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called to create share servers for shares using information provided within a
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`share network`. This information will be provided to one of the enabled
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network plugins that will handle reservation, creation and deletion of
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network resources including `IP addresses` and `network interfaces`.
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As an exception, any share drivers that use Nova for the creation of share
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servers should use some wrapper for network plugins, because Nova handles the
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creation of network resources for its VMs. In the Manila Kilo version, only
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the `Generic driver` uses Nova with the help of its own `network helpers`,
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which serve the same needs but are related only to this share driver.
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.. _what_network_plugins_are_available:
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What network plugins are available?
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-----------------------------------
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There are three different network plugins and five python classes in Manila:
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1 Network plugin for using the `OpenStack` networking project `Neutron`.
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It allows one to use any network segmentation that Neutron supports. It is
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up to each share driver to support at least one network segmentation type.
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1.1 `manila.network.neutron.neutron_network_plugin.NeutronNetworkPlugin`.
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This is the default network plugin. It requires that `neutron_net_id` and
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`neutron_subnet_id` are provided when defining the share network that
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will be used for the creation of share servers. The user may define any
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number of share networks corresponding to the various physical network
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segments in a tenant environment.
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1.2 `manila.network.neutron.neutron_network_plugin.NeutronSingleNetworkPlugin`.
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This is a simplification of the previous case. It accepts values for
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`neutron_net_id` and `neutron_subnet_id` from the Manila configuration
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file and uses one network for all shares.
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When only a single network is needed, the NeutronSingleNetworkPlugin (1.2)
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is a simple solution. Otherwise NeutronNetworkPlugin (1.1) should be chosen.
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2 Network plugin for working with OpenStack native networking from `Nova`.
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It supports either flat networks or VLAN-segmented networks.
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2.1 `manila.network.nova_network_plugin.NovaNetworkPlugin`.
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This plugin serves the networking needs when `Nova networking` is
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configured in the cloud instead of Neutron. It requires a single
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parameter, `nova_net_id`.
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2.2 `manila.network.nova_network_plugin.NovaSingleNetworkPlugin`.
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This one works in the same way as the previous one with one difference.
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It takes nova_net_id from the Manila configuration file and creates
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share servers using only one network.
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When only a single network is needed, the NovaSingleNetworkPlugin (2.2)
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is a simple solution. Otherwise NovaNetworkPlugin (1.1) should be chosen.
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3 Network plugin for specifying networks independently from OpenStack
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networking services.
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3.1 `manila.network.standalone_network_plugin.StandaloneNetworkPlugin`.
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This plug-in uses a pre-existing network that is available to the
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manila-share host. This network may be handled either by OpenStack or be
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created independently by any other means. The plugin supports any type of
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network - flat and segmented. As above, it is completely up to the driver
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to support the network type for which the network plugin is configured.
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.. note::
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These network plugins were introduced in the OpenStack Kilo release.
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In the OpenStack Juno version, only NeutronNetworkPlugin is available.
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Plugins in 1.2, 2.2, and 3.1 all ignore what the user supplies in the
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share_network and instead always provide IP addresses from a single
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network.
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Approaches for setup of network plugins
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---------------------------------------
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Each manila-share service may have its own network plugin or one that is
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shared with other services. All configuration options for network plugins may
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be set in three ways by priorities:
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- Using a separate configuration group.
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For this case, the config opt `network_config_group` should be defined in
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the config group of the manila-share service and have the name of
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the config group with the defined options for the network plugin.
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First priority.
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- Using config group of manila-share service. Second priority.
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- Using config group `[DEFAULT]`. Lowest priority.
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A specific network plugin is enabled by setting the configuration option
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`network_api_class` to one of the values defined in the previous section
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:ref:`what_network_plugins_are_available`. This option can be defined in any
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of the approaches above along with options for the network plugin itself.
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Example of network plugin configuration
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---------------------------------------
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Let's configure three manila-share services that use different approaches for
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configuration of network plugins.
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As noted in section :ref:`what_network_plugins_are_available`, in the Kilo
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version of OpenStack there are 5 (five) network plugins, three of which
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require configuration options - 1.2, 2.2 and 3.1.
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We will use a configuration example using network plugin 1.2, the
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NeutronSingleNetworkPlugin.
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Here is the configuration::
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[DEFAULT]
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enabled_share_backends = SHARE_BACKEND_1,SHARE_BACKEND_2,SHARE_BACKEND_3
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network_api_class = manila.network.neutron.neutron_network_plugin.NeutronSingleNetworkPlugin
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neutron_net_id = neutron_net_id_DEFAULT
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neutron_subnet_id = neutron_subnet_id_DEFAULT
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[NETWORK_PLUGIN]
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neutron_net_id = neutron_net_id_NETWORK_PLUGIN
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neutron_subnet_id = neutron_subnet_id_NETWORK_PLUGIN
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[SHARE_BACKEND_1]
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# This share backend is enabled for handling of share servers using opts
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# for network plugin defined in separate config group called `NETWORK_PLUGIN`.
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network_config_group = NETWORK_PLUGIN
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driver_handles_share_servers = True
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[SHARE_BACKEND_2]
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# This share backend is enabled for handling of share servers using opts
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# defined in its own config group.
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driver_handles_share_servers = True
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neutron_net_id = neutron_net_id_SHARE_BACKEND_2
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neutron_subnet_id = neutron_subnet_id_SHARE_BACKEND_2
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[SHARE_BACKEND_3]
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# This share backend is enabled for handling of share servers using opts
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# defined in config group [DEFAULT].
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driver_handles_share_servers = True
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Here is a list of neutron_net_id and neutron_subnet_id values for our
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manila-share services:
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- [SHARE_BACKEND_1]
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- neutron_net_id=neutron_net_id_NETWORK_PLUGIN
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- neutron_subnet_id=neutron_subnet_id_NETWORK_PLUGIN
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- [SHARE_BACKEND_2]
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- neutron_net_id=neutron_net_idSHARE_BACKEND_2
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- neutron_subnet_id=neutron_subnet_id_SHARE_BACKEND_2
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- [SHARE_BACKEND_3]
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- neutron_net_id=neutron_net_id_DEFAULT
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- neutron_subnet_id=neutron_subnet_id_DEFAULT
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The value for option network_api_class was taken by each manila-share service
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from group [DEFAULT] because it was not redefined in other places.
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.. note::
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The last approach - use of [DEFAULT] group - is not preferred for setting
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network plugin options and will generate warnings in your manila-share
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logs. Either of the first two approaches is recommended.
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