openstack-manuals/doc/config-reference/source/shared-file-systems/overview.rst

Introduction to the Shared File Systems service

The Shared File Systems service provides shared file systems that Compute instances can consume.

The Shared File Systems service provides:

manila-api

A WSGI app that authenticates and routes requests throughout the Shared File Systems service. It supports the OpenStack APIs.

manila-data

A standalone service whose purpose is to receive requests, process data operations with potentially long running time such as copying, share migration or backup.

manila-scheduler

Schedules and routes requests to the appropriate share service. The scheduler uses configurable filters and weighers to route requests. The Filter Scheduler is the default and enables filters on things like Capacity, Availability Zone, Share Types, and Capabilities as well as custom filters.

manila-share

Manages back-end devices that provide shared file systems. A manila-share service can run in one of two modes, with or without handling of share servers. Share servers export file shares via share networks. When share servers are not used, the networking requirements are handled outside of Manila.

The Shared File Systems service contains the following components:

Back-end storage devices

The Shared File Services service requires some form of back-end shared file system provider that the service is built on. The reference implementation uses the Block Storage service (Cinder) and a service VM to provide shares. Additional drivers are used to access shared file systems from a variety of vendor solutions.

Users and tenants (projects)

The Shared File Systems service can be used by many different cloud computing consumers or customers (tenants on a shared system), using role-based access assignments. Roles control the actions that a user is allowed to perform. In the default configuration, most actions do not require a particular role unless they are restricted to administrators, but this can be configured by the system administrator in the appropriate policy.json file that maintains the rules. A user's access to manage particular shares is limited by tenant. Guest access to mount and use shares is secured by IP and/or user access rules. Quotas used to control resource consumption across available hardware resources are per tenant.

For tenants, quota controls are available to limit:

• The number of shares that can be created.
• The number of gigabytes that can be provisioned for shares.
• The number of share snapshots that can be created.
• The number of gigabytes that can be provisioned for share snapshots.
• The number of share networks that can be created.

You can revise the default quota values with the Shared File Systems CLI, so the limits placed by quotas are editable by admin users.

Shares, snapshots, and share networks

The basic resources offered by the Shared File Systems service are shares, snapshots and share networks:

Shares

A share is a unit of storage with a protocol, a size, and an access list. Shares are the basic primitive provided by Manila. All shares exist on a backend. Some shares are associated with share networks and share servers. The main protocols supported are NFS and CIFS, but other protocols are supported as well.

Snapshots

A snapshot is a point in time copy of a share. Snapshots can only be used to create new shares (containing the snapshotted data). Shares cannot be deleted until all associated snapshots are deleted.

Share networks

A share network is a tenant-defined object that informs Manila about the security and network configuration for a group of shares. Share networks are only relevant for backends that manage share servers. A share network contains a security service and network/subnet.