OpenStackClient has a consistent and predictable format for all of its commands.

Commands take the form:

openstack [<global-options>] <object-1> <action> [<object-2>] [<command-arguments>]

• All long options names begin with two dashes (--) and use a single dash (-) internally between words (--like-this). Underscores (_) are not used in option names.

Global options are global in the sense that they apply to every command invocation regardless of action to be performed. They include authentication credentials and API version selection. Most global options have a corresponding environment variable that may also be used to set the value. If both are present, the command-line option takes priority. The environment variable names are derived from the option name by dropping the leading dashes (--), converting each embedded dash (-) to an underscore (_), and converting to upper case.

For example, the default value of --os-username can be set by defining the environment variable OS_USERNAME.

Commands consist of an object described by one or more words followed by an action. Commands that require two objects have the primary object ahead of the action and the secondary object after the action. Any positional arguments identifying the objects shall appear in the same order as the objects. In badly formed English it is expressed as "(Take) object1 (and perform) action (using) object2 (to it)."

<object-1> <action> <object-2>

Examples:

group add user <group> <user>

volume type list   # 'volume type' is a two-word single object

Each command may have its own set of options distinct from the global options. They follow the same style as the global options and always appear between the command and any positional arguments the command requires.

The objects consist of one or more words to compose a unique name. Occasionally when multiple APIs have a common name with common overlapping purposes there will be options to select which object to use, or the API resources will be merged, as in the quota object that has options referring to both Compute and Volume quotas.

• access token: Identity - long-lived OAuth-based token
• aggregate: Compute - a grouping of servers
• backup: Volume - a volume copy
• console log: Compute - a text dump of a server's console
• console url: Compute - a URL to a server's remote console
• consumer: Identity - OAuth-based delegatee
• container: Object Store - a grouping of objects
• credential: Identity - specific to identity providers
• domain: Identity - a grouping of projects
• endpoint: Identity - the base URL used to contact a specific service
• extension: Compute, Identity, Volume - additional APIs available
• flavor: Compute - pre-defined configurations of servers: ram, root disk, etc
• group: Identity - a grouping of users
• host: Compute - the physical computer running a hypervisor
• hypervisor: Compute - the virtual machine manager
• identity provider: Identity - a source of users and authentication
• image: Image - a disk image
• ip fixed: Compute, Network - an internal IP address assigned to a server
• ip floating: Compute, Network - a public IP address that can be mapped to a server
• keypair: Compute - an SSH public key
• limits: Compute, Volume - resource usage limits
• module: internal - installed Python modules in the OSC process
• network: Network - a virtual network for connecting servers and other resources
• object: Object Store - a single file in the Object Store
• policy: Identity - determines authorization
• project: Identity - the owner of a group of resources
• quota: Compute, Volume - limit on resource usage
• request token: Identity - temporary OAuth-based token
• role: Identity - a policy object used to determine authorization
• security group: Compute, Network - groups of network access rules
• security group rule: Compute, Network - the individual rules that define protocol/IP/port access
• server: Compute - a virtual machine instance
• service: Identity - a cloud service
• snapshot: Volume - a point-in-time copy of a volume
• token: Identity - the magic text used to determine access
• user: Identity - individuals using cloud resources
• volume: Volume - block volumes
• volume type: Volume - deployment-specific types of volumes available

The actions used by OpenStackClient are defined below to provide a consistent meaning to each action. Many of them have logical opposite actions. Those actions with an opposite action are noted in parens if applicable.

• authorize - authorize a token (used in OAuth)
• add (remove) - add some object to a container object; the command is built in the order of container add object <container> <object>, the positional arguments appear in the same order
• create (delete) - create a new occurrence of the specified object
• delete (create) - delete a specific occurrence of the specified object
• issue (revoke) - issue a token
• list - display summary information about multiple objects
• lock (unlock)
• migrate - move a server to a different host; --live performs a live migration if possible
• pause (unpause) - stop a server and leave it in memory
• reboot - forcibly reboot a server
• rebuild - rebuild a server using (most of) the same arguments as in the original create
• remove (add) - remove an object from a group of objects
• rescue (unrescue) - reboot a server in a special rescue mode allowing access to the original disks
• resize - change a server's flavor
• resume (suspend) - return a suspended server to running state
• revoke (issue) - revoke a token
• save - download an object locally
• set (unset) - set a property on the object, formerly called metadata
• show - display detailed information about the specific object
• suspend (resume) - stop a server and save to disk freeing memory
• unlock (lock)
• unpause (pause) - return a paused server to running state
• unrescue (rescue) - return a server to normal boot mode
• unset (set) - remove an attribute of the object

The command structure is designed to support seamless addition of plugin command modules via setuptools entry points. The plugin commands must be subclasses of Cliff's command.Command object. See :doc:`plugins` for more information.

Commands are added to the client using setuptools entry points in setup.cfg. There is a single common group openstack.cli for commands that are not versioned, and a group for each combination of OpenStack API and version that is supported. For example, to support Identity API v3 there is a group called openstack.identity.v3 that contains the individual commands. The command entry points have the form:

action_object = fully.qualified.module.vXX.object:ActionObject

For example, the list user command for the Identity API is identified in setup.cfg with:

openstack.identity.v3 =
    # ...
    list_user = openstackclient.identity.v3.user:ListUser
    # ...