Key concepts

Share

In the Shared File Systems service share is the
fundamental resource unit allocated by the Shared File System service.
It represents an allocation of a persistent, readable, and writable
filesystems. Compute instances access these filesystems. Depending on
the deployment configuration, clients outside of OpenStack can also
access the filesystem.

Share instance

This concept is tied with share and represents created
resource on specific back end, when share represents
abstraction between end user and back-end storages. In common cases, it
is one-to-one relation. One single share has more than one
share instance in two cases:

• When share migration is being applied
• When share replication is enabled

Therefore, each share instance stores information
specific to real allocated resource on storage. And share
represents the information that is common for
share instances. A user with member role will
not be able to work with it directly. Only a user with
admin role has rights to perform actions against specific
share instances.

Snapshot

A snapshot is a point-in-time, read-only copy of a
share. You can create Snapshots from an
existing, operational share regardless of whether a client
has mounted the file system. A snapshot can serve as the
content source for a new share. Specify the Create
from snapshot option when creating a new share on
the dashboard.

Storage Pools

With the Kilo release of OpenStack, Shared File Systems can use
storage pools. The storage may present one or more logical
storage resource pools that the Shared File Systems service will select
as a storage location when provisioning shares.

Share Type

Share type is an abstract collection of criteria used to
characterize shares. They are most commonly used to create
a hierarchy of functional capabilities. This hierarchy represents tiered
storage services levels. For example, an administrator might define a
premium share type that indicates a greater level of
performance than a basic share type. Premium represents the
best performance level.

Share Access Rules

Share access rules define which users can access a
particular share. For example, administrators can declare
rules for NFS shares by listing the valid IP networks which will access
the share. List the IP networks in CIDR notation.

Security Services

Security services allow granular client access rules for
administrators. They can declare rules for authentication or
authorization to access share content. External services
including LDAP, Active Directory, and Kerberos can be declared as
resources. Examine and consult these resources when making an access
decision for a particular share. You can associate
Shares with multiple security services, but only one
service per one type.

Share Networks

A share network is an object that defines a relationship
between a project network and subnet, as defined in an OpenStack
Networking service or Compute service. The share network is
also defined in shares created by the same project. A
project may find it desirable to provision shares such that
only instances connected to a particular OpenStack-defined network have
access to the share. Also, security services
can be attached to share networks, because most of auth
protocols require some interaction with network services.

The Shared File Systems service has the ability to work outside of
OpenStack. That is due to the StandaloneNetworkPlugin. The
plugin is compatible with any network platform, and does not require
specific network services in OpenStack like Compute or Networking
service. You can set the network parameters in the
manila.conf file.

Share Servers

A share server is a logical entity that hosts the shares
created on a specific share network. A
share server may be a configuration object within the
storage controller, or it may represent logical resources provisioned
within an OpenStack deployment used to support the data path used to
access shares.

Share servers interact with network services to
determine the appropriate IP addresses on which to export
shares according to the related share network.
The Shared File Systems service has a pluggable network model that
allows share servers to work with different implementations
of the Networking service.