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+.. _user-management:
+
+=================
+ User Management
+=================
+
+This document describes :term:`Ceph Client` users, and their authentication and
+authorization with the :term:`Ceph Storage Cluster`. Users are either
+individuals or system actors such as applications, which use Ceph clients to
+interact with the Ceph Storage Cluster daemons.
+
+.. ditaa::
+ +-----+
+ | {o} |
+ | |
+ +--+--+ /---------\ /---------\
+ | | Ceph | | Ceph |
+ ---+---*----->| |<------------->| |
+ | uses | Clients | | Servers |
+ | \---------/ \---------/
+ /--+--\
+ | |
+ | |
+ actor
+
+
+When Ceph runs with authentication and authorization enabled (enabled by
+default), you must specify a user name and a keyring containing the secret key
+of the specified user (usually via the command line). If you do not specify a
+user name, Ceph will use ``client.admin`` as the default user name. If you do
+not specify a keyring, Ceph will look for a keyring via the ``keyring`` setting
+in the Ceph configuration. For example, if you execute the ``ceph health``
+command without specifying a user or keyring::
+
+ ceph health
+
+Ceph interprets the command like this::
+
+ ceph -n client.admin --keyring=/etc/ceph/ceph.client.admin.keyring health
+
+Alternatively, you may use the ``CEPH_ARGS`` environment variable to avoid
+re-entry of the user name and secret.
+
+For details on configuring the Ceph Storage Cluster to use authentication,
+see `Cephx Config Reference`_. For details on the architecture of Cephx, see
+`Architecture - High Availability Authentication`_.
+
+
+Background
+==========
+
+Irrespective of the type of Ceph client (e.g., Block Device, Object Storage,
+Filesystem, native API, etc.), Ceph stores all data as objects within `pools`_.
+Ceph users must have access to pools in order to read and write data.
+Additionally, Ceph users must have execute permissions to use Ceph's
+administrative commands. The following concepts will help you understand Ceph
+user management.
+
+
+User
+----
+
+A user is either an individual or a system actor such as an application.
+Creating users allows you to control who (or what) can access your Ceph Storage
+Cluster, its pools, and the data within pools.
+
+Ceph has the notion of a ``type`` of user. For the purposes of user management,
+the type will always be ``client``. Ceph identifies users in period (.)
+delimited form consisting of the user type and the user ID: for example,
+``TYPE.ID``, ``client.admin``, or ``client.user1``. The reason for user typing
+is that Ceph Monitors, OSDs, and Metadata Servers also use the Cephx protocol,
+but they are not clients. Distinguishing the user type helps to distinguish
+between client users and other users--streamlining access control, user
+monitoring and traceability.
+
+Sometimes Ceph's user type may seem confusing, because the Ceph command line
+allows you to specify a user with or without the type, depending upon your
+command line usage. If you specify ``--user`` or ``--id``, you can omit the
+type. So ``client.user1`` can be entered simply as ``user1``. If you specify
+``--name`` or ``-n``, you must specify the type and name, such as
+``client.user1``. We recommend using the type and name as a best practice
+wherever possible.
+
+.. note:: A Ceph Storage Cluster user is not the same as a Ceph Object Storage
+ user or a Ceph Filesystem user. The Ceph Object Gateway uses a Ceph Storage
+ Cluster user to communicate between the gateway daemon and the storage
+ cluster, but the gateway has its own user management functionality for end
+ users. The Ceph Filesystem uses POSIX semantics. The user space associated
+ with the Ceph Filesystem is not the same as a Ceph Storage Cluster user.
+
+
+
+Authorization (Capabilities)
+----------------------------
+
+Ceph uses the term "capabilities" (caps) to describe authorizing an
+authenticated user to exercise the functionality of the monitors, OSDs and
+metadata servers. Capabilities can also restrict access to data within a pool,
+a namespace within a pool, or a set of pools based on their application tags.
+A Ceph administrative user sets a user's capabilities when creating or updating
+a user.
+
+Capability syntax follows the form::
+
+ {daemon-type} '{cap-spec}[, {cap-spec} ...]'
+
+- **Monitor Caps:** Monitor capabilities include ``r``, ``w``, ``x`` access
+ settings or ``profile {name}``. For example::
+
+ mon 'allow {access-spec} [network {network/prefix}]'
+
+ mon 'profile {name}'
+
+ The ``{access-spec}`` syntax is as follows: ::
+
+ * | all | [r][w][x]
+
+ The optional ``{network/prefix}`` is a standard network name and
+ prefix length in CIDR notation (e.g., ``10.3.0.0/16``). If present,
+ the use of this capability is restricted to clients connecting from
+ this network.
+
+- **OSD Caps:** OSD capabilities include ``r``, ``w``, ``x``, ``class-read``,
+ ``class-write`` access settings or ``profile {name}``. Additionally, OSD
+ capabilities also allow for pool and namespace settings. ::
+
+ osd 'allow {access-spec} [{match-spec}] [network {network/prefix}]'
+
+ osd 'profile {name} [pool={pool-name} [namespace={namespace-name}]] [network {network/prefix}]'
+
+ The ``{access-spec}`` syntax is either of the following: ::
+
+ * | all | [r][w][x] [class-read] [class-write]
+
+ class {class name} [{method name}]
+
+ The optional ``{match-spec}`` syntax is either of the following: ::
+
+ pool={pool-name} [namespace={namespace-name}] [object_prefix {prefix}]
+
+ [namespace={namespace-name}] tag {application} {key}={value}
+
+ The optional ``{network/prefix}`` is a standard network name and
+ prefix length in CIDR notation (e.g., ``10.3.0.0/16``). If present,
+ the use of this capability is restricted to clients connecting from
+ this network.
+
+- **Manager Caps:** Manager (``ceph-mgr``) capabilities include
+ ``r``, ``w``, ``x`` access settings or ``profile {name}``. For example: ::
+
+ mgr 'allow {access-spec} [network {network/prefix}]'
+
+ mgr 'profile {name} [{key1} {match-type} {value1} ...] [network {network/prefix}]'
+
+ Manager capabilities can also be specified for specific commands,
+ all commands exported by a built-in manager service, or all commands
+ exported by a specific add-on module. For example: ::
+
+ mgr 'allow command "{command-prefix}" [with {key1} {match-type} {value1} ...] [network {network/prefix}]'
+
+ mgr 'allow service {service-name} {access-spec} [network {network/prefix}]'
+
+ mgr 'allow module {module-name} [with {key1} {match-type} {value1} ...] {access-spec} [network {network/prefix}]'
+
+ The ``{access-spec}`` syntax is as follows: ::
+
+ * | all | [r][w][x]
+
+ The ``{service-name}`` is one of the following: ::
+
+ mgr | osd | pg | py
+
+ The ``{match-type}`` is one of the following: ::
+
+ = | prefix | regex
+
+- **Metadata Server Caps:** For administrators, use ``allow *``. For all
+ other users, such as CephFS clients, consult :doc:`/cephfs/client-auth`
+
+
+.. note:: The Ceph Object Gateway daemon (``radosgw``) is a client of the
+ Ceph Storage Cluster, so it is not represented as a Ceph Storage
+ Cluster daemon type.
+
+The following entries describe each access capability.
+
+``allow``
+
+:Description: Precedes access settings for a daemon. Implies ``rw``
+ for MDS only.
+
+
+``r``
+
+:Description: Gives the user read access. Required with monitors to retrieve
+ the CRUSH map.
+
+
+``w``
+
+:Description: Gives the user write access to objects.
+
+
+``x``
+
+:Description: Gives the user the capability to call class methods
+ (i.e., both read and write) and to conduct ``auth``
+ operations on monitors.
+
+
+``class-read``
+
+:Descriptions: Gives the user the capability to call class read methods.
+ Subset of ``x``.
+
+
+``class-write``
+
+:Description: Gives the user the capability to call class write methods.
+ Subset of ``x``.
+
+
+``*``, ``all``
+
+:Description: Gives the user read, write and execute permissions for a
+ particular daemon/pool, and the ability to execute
+ admin commands.
+
+The following entries describe valid capability profiles:
+
+``profile osd`` (Monitor only)
+
+:Description: Gives a user permissions to connect as an OSD to other OSDs or
+ monitors. Conferred on OSDs to enable OSDs to handle replication
+ heartbeat traffic and status reporting.
+
+
+``profile mds`` (Monitor only)
+
+:Description: Gives a user permissions to connect as a MDS to other MDSs or
+ monitors.
+
+
+``profile bootstrap-osd`` (Monitor only)
+
+:Description: Gives a user permissions to bootstrap an OSD. Conferred on
+ deployment tools such as ``ceph-volume``, ``ceph-deploy``, etc.
+ so that they have permissions to add keys, etc. when
+ bootstrapping an OSD.
+
+
+``profile bootstrap-mds`` (Monitor only)
+
+:Description: Gives a user permissions to bootstrap a metadata server.
+ Conferred on deployment tools such as ``ceph-deploy``, etc.
+ so they have permissions to add keys, etc. when bootstrapping
+ a metadata server.
+
+``profile bootstrap-rbd`` (Monitor only)
+
+:Description: Gives a user permissions to bootstrap an RBD user.
+ Conferred on deployment tools such as ``ceph-deploy``, etc.
+ so they have permissions to add keys, etc. when bootstrapping
+ an RBD user.
+
+``profile bootstrap-rbd-mirror`` (Monitor only)
+
+:Description: Gives a user permissions to bootstrap an ``rbd-mirror`` daemon
+ user. Conferred on deployment tools such as ``ceph-deploy``, etc.
+ so they have permissions to add keys, etc. when bootstrapping
+ an ``rbd-mirror`` daemon.
+
+``profile rbd`` (Manager, Monitor, and OSD)
+
+:Description: Gives a user permissions to manipulate RBD images. When used
+ as a Monitor cap, it provides the minimal privileges required
+ by an RBD client application; this includes the ability
+ to blacklist other client users. When used as an OSD cap, it
+ provides read-write access to the specified pool to an
+ RBD client application. The Manager cap supports optional
+ ``pool`` and ``namespace`` keyword arguments.
+
+``profile rbd-mirror`` (Monitor only)
+
+:Description: Gives a user permissions to manipulate RBD images and retrieve
+ RBD mirroring config-key secrets. It provides the minimal
+ privileges required for the ``rbd-mirror`` daemon.
+
+``profile rbd-read-only`` (Manager and OSD)
+
+:Description: Gives a user read-only permissions to RBD images. The Manager
+ cap supports optional ``pool`` and ``namespace`` keyword
+ arguments.
+
+
+Pool
+----
+
+A pool is a logical partition where users store data.
+In Ceph deployments, it is common to create a pool as a logical partition for
+similar types of data. For example, when deploying Ceph as a backend for
+OpenStack, a typical deployment would have pools for volumes, images, backups
+and virtual machines, and users such as ``client.glance``, ``client.cinder``,
+etc.
+
+Application Tags
+----------------
+
+Access may be restricted to specific pools as defined by their application
+metadata. The ``*`` wildcard may be used for the ``key`` argument, the
+``value`` argument, or both. ``all`` is a synony for ``*``.
+
+Namespace
+---------
+
+Objects within a pool can be associated to a namespace--a logical group of
+objects within the pool. A user's access to a pool can be associated with a
+namespace such that reads and writes by the user take place only within the
+namespace. Objects written to a namespace within the pool can only be accessed
+by users who have access to the namespace.
+
+.. note:: Namespaces are primarily useful for applications written on top of
+ ``librados`` where the logical grouping can alleviate the need to create
+ different pools. Ceph Object Gateway (from ``luminous``) uses namespaces for various
+ metadata objects.
+
+The rationale for namespaces is that pools can be a computationally expensive
+method of segregating data sets for the purposes of authorizing separate sets
+of users. For example, a pool should have ~100 placement groups per OSD. So an
+exemplary cluster with 1000 OSDs would have 100,000 placement groups for one
+pool. Each pool would create another 100,000 placement groups in the exemplary
+cluster. By contrast, writing an object to a namespace simply associates the
+namespace to the object name with out the computational overhead of a separate
+pool. Rather than creating a separate pool for a user or set of users, you may
+use a namespace. **Note:** Only available using ``librados`` at this time.
+
+Access may be restricted to specific RADOS namespaces using the ``namespace``
+capability. Limited globbing of namespaces is supported; if the last character
+of the specified namespace is ``*``, then access is granted to any namespace
+starting with the provided argument.
+
+
+Managing Users
+==============
+
+User management functionality provides Ceph Storage Cluster administrators with
+the ability to create, update and delete users directly in the Ceph Storage
+Cluster.
+
+When you create or delete users in the Ceph Storage Cluster, you may need to
+distribute keys to clients so that they can be added to keyrings. See `Keyring
+Management`_ for details.
+
+
+List Users
+----------
+
+To list the users in your cluster, execute the following::
+
+ ceph auth ls
+
+Ceph will list out all users in your cluster. For example, in a two-node
+exemplary cluster, ``ceph auth ls`` will output something that looks like
+this::
+
+ installed auth entries:
+
+ osd.0
+ key: AQCvCbtToC6MDhAATtuT70Sl+DymPCfDSsyV4w==
+ caps: [mon] allow profile osd
+ caps: [osd] allow *
+ osd.1
+ key: AQC4CbtTCFJBChAAVq5spj0ff4eHZICxIOVZeA==
+ caps: [mon] allow profile osd
+ caps: [osd] allow *
+ client.admin
+ key: AQBHCbtT6APDHhAA5W00cBchwkQjh3dkKsyPjw==
+ caps: [mds] allow
+ caps: [mon] allow *
+ caps: [osd] allow *
+ client.bootstrap-mds
+ key: AQBICbtTOK9uGBAAdbe5zcIGHZL3T/u2g6EBww==
+ caps: [mon] allow profile bootstrap-mds
+ client.bootstrap-osd
+ key: AQBHCbtT4GxqORAADE5u7RkpCN/oo4e5W0uBtw==
+ caps: [mon] allow profile bootstrap-osd
+
+
+Note that the ``TYPE.ID`` notation for users applies such that ``osd.0`` is a
+user of type ``osd`` and its ID is ``0``, ``client.admin`` is a user of type
+``client`` and its ID is ``admin`` (i.e., the default ``client.admin`` user).
+Note also that each entry has a ``key: <value>`` entry, and one or more
+``caps:`` entries.
+
+You may use the ``-o {filename}`` option with ``ceph auth ls`` to
+save the output to a file.
+
+
+Get a User
+----------
+
+To retrieve a specific user, key and capabilities, execute the
+following::
+
+ ceph auth get {TYPE.ID}
+
+For example::
+
+ ceph auth get client.admin
+
+You may also use the ``-o {filename}`` option with ``ceph auth get`` to
+save the output to a file. Developers may also execute the following::
+
+ ceph auth export {TYPE.ID}
+
+The ``auth export`` command is identical to ``auth get``.
+
+
+
+Add a User
+----------
+
+Adding a user creates a username (i.e., ``TYPE.ID``), a secret key and
+any capabilities included in the command you use to create the user.
+
+A user's key enables the user to authenticate with the Ceph Storage Cluster.
+The user's capabilities authorize the user to read, write, or execute on Ceph
+monitors (``mon``), Ceph OSDs (``osd``) or Ceph Metadata Servers (``mds``).
+
+There are a few ways to add a user:
+
+- ``ceph auth add``: This command is the canonical way to add a user. It
+ will create the user, generate a key and add any specified capabilities.
+
+- ``ceph auth get-or-create``: This command is often the most convenient way
+ to create a user, because it returns a keyfile format with the user name
+ (in brackets) and the key. If the user already exists, this command
+ simply returns the user name and key in the keyfile format. You may use the
+ ``-o {filename}`` option to save the output to a file.
+
+- ``ceph auth get-or-create-key``: This command is a convenient way to create
+ a user and return the user's key (only). This is useful for clients that
+ need the key only (e.g., libvirt). If the user already exists, this command
+ simply returns the key. You may use the ``-o {filename}`` option to save the
+ output to a file.
+
+When creating client users, you may create a user with no capabilities. A user
+with no capabilities is useless beyond mere authentication, because the client
+cannot retrieve the cluster map from the monitor. However, you can create a
+user with no capabilities if you wish to defer adding capabilities later using
+the ``ceph auth caps`` command.
+
+A typical user has at least read capabilities on the Ceph monitor and
+read and write capability on Ceph OSDs. Additionally, a user's OSD permissions
+are often restricted to accessing a particular pool. ::
+
+ ceph auth add client.john mon 'allow r' osd 'allow rw pool=liverpool'
+ ceph auth get-or-create client.paul mon 'allow r' osd 'allow rw pool=liverpool'
+ ceph auth get-or-create client.george mon 'allow r' osd 'allow rw pool=liverpool' -o george.keyring
+ ceph auth get-or-create-key client.ringo mon 'allow r' osd 'allow rw pool=liverpool' -o ringo.key
+
+
+.. important:: If you provide a user with capabilities to OSDs, but you DO NOT
+ restrict access to particular pools, the user will have access to ALL
+ pools in the cluster!
+
+
+.. _modify-user-capabilities:
+
+Modify User Capabilities
+------------------------
+
+The ``ceph auth caps`` command allows you to specify a user and change the
+user's capabilities. Setting new capabilities will overwrite current capabilities.
+To view current capabilities run ``ceph auth get USERTYPE.USERID``. To add
+capabilities, you should also specify the existing capabilities when using the form::
+
+ ceph auth caps USERTYPE.USERID {daemon} 'allow [r|w|x|*|...] [pool={pool-name}] [namespace={namespace-name}]' [{daemon} 'allow [r|w|x|*|...] [pool={pool-name}] [namespace={namespace-name}]']
+
+For example::
+
+ ceph auth get client.john
+ ceph auth caps client.john mon 'allow r' osd 'allow rw pool=liverpool'
+ ceph auth caps client.paul mon 'allow rw' osd 'allow rwx pool=liverpool'
+ ceph auth caps client.brian-manager mon 'allow *' osd 'allow *'
+
+See `Authorization (Capabilities)`_ for additional details on capabilities.
+
+
+Delete a User
+-------------
+
+To delete a user, use ``ceph auth del``::
+
+ ceph auth del {TYPE}.{ID}
+
+Where ``{TYPE}`` is one of ``client``, ``osd``, ``mon``, or ``mds``,
+and ``{ID}`` is the user name or ID of the daemon.
+
+
+Print a User's Key
+------------------
+
+To print a user's authentication key to standard output, execute the following::
+
+ ceph auth print-key {TYPE}.{ID}
+
+Where ``{TYPE}`` is one of ``client``, ``osd``, ``mon``, or ``mds``,
+and ``{ID}`` is the user name or ID of the daemon.
+
+Printing a user's key is useful when you need to populate client
+software with a user's key (e.g., libvirt). ::
+
+ mount -t ceph serverhost:/ mountpoint -o name=client.user,secret=`ceph auth print-key client.user`
+
+
+Import a User(s)
+----------------
+
+To import one or more users, use ``ceph auth import`` and
+specify a keyring::
+
+ ceph auth import -i /path/to/keyring
+
+For example::
+
+ sudo ceph auth import -i /etc/ceph/ceph.keyring
+
+
+.. note:: The ceph storage cluster will add new users, their keys and their
+ capabilities and will update existing users, their keys and their
+ capabilities.
+
+
+Keyring Management
+==================
+
+When you access Ceph via a Ceph client, the Ceph client will look for a local
+keyring. Ceph presets the ``keyring`` setting with the following four keyring
+names by default so you don't have to set them in your Ceph configuration file
+unless you want to override the defaults (not recommended):
+
+- ``/etc/ceph/$cluster.$name.keyring``
+- ``/etc/ceph/$cluster.keyring``
+- ``/etc/ceph/keyring``
+- ``/etc/ceph/keyring.bin``
+
+The ``$cluster`` metavariable is your Ceph cluster name as defined by the
+name of the Ceph configuration file (i.e., ``ceph.conf`` means the cluster name
+is ``ceph``; thus, ``ceph.keyring``). The ``$name`` metavariable is the user
+type and user ID (e.g., ``client.admin``; thus, ``ceph.client.admin.keyring``).
+
+.. note:: When executing commands that read or write to ``/etc/ceph``, you may
+ need to use ``sudo`` to execute the command as ``root``.
+
+After you create a user (e.g., ``client.ringo``), you must get the key and add
+it to a keyring on a Ceph client so that the user can access the Ceph Storage
+Cluster.
+
+The `User Management`_ section details how to list, get, add, modify and delete
+users directly in the Ceph Storage Cluster. However, Ceph also provides the
+``ceph-authtool`` utility to allow you to manage keyrings from a Ceph client.
+
+
+Create a Keyring
+----------------
+
+When you use the procedures in the `Managing Users`_ section to create users,
+you need to provide user keys to the Ceph client(s) so that the Ceph client
+can retrieve the key for the specified user and authenticate with the Ceph
+Storage Cluster. Ceph Clients access keyrings to lookup a user name and
+retrieve the user's key.
+
+The ``ceph-authtool`` utility allows you to create a keyring. To create an
+empty keyring, use ``--create-keyring`` or ``-C``. For example::
+
+ ceph-authtool --create-keyring /path/to/keyring
+
+When creating a keyring with multiple users, we recommend using the cluster name
+(e.g., ``$cluster.keyring``) for the keyring filename and saving it in the
+``/etc/ceph`` directory so that the ``keyring`` configuration default setting
+will pick up the filename without requiring you to specify it in the local copy
+of your Ceph configuration file. For example, create ``ceph.keyring`` by
+executing the following::
+
+ sudo ceph-authtool -C /etc/ceph/ceph.keyring
+
+When creating a keyring with a single user, we recommend using the cluster name,
+the user type and the user name and saving it in the ``/etc/ceph`` directory.
+For example, ``ceph.client.admin.keyring`` for the ``client.admin`` user.
+
+To create a keyring in ``/etc/ceph``, you must do so as ``root``. This means
+the file will have ``rw`` permissions for the ``root`` user only, which is
+appropriate when the keyring contains administrator keys. However, if you
+intend to use the keyring for a particular user or group of users, ensure
+that you execute ``chown`` or ``chmod`` to establish appropriate keyring
+ownership and access.
+
+
+Add a User to a Keyring
+-----------------------
+
+When you `Add a User`_ to the Ceph Storage Cluster, you can use the `Get a
+User`_ procedure to retrieve a user, key and capabilities and save the user to a
+keyring.
+
+When you only want to use one user per keyring, the `Get a User`_ procedure with
+the ``-o`` option will save the output in the keyring file format. For example,
+to create a keyring for the ``client.admin`` user, execute the following::
+
+ sudo ceph auth get client.admin -o /etc/ceph/ceph.client.admin.keyring
+
+Notice that we use the recommended file format for an individual user.
+
+When you want to import users to a keyring, you can use ``ceph-authtool``
+to specify the destination keyring and the source keyring.
+For example::
+
+ sudo ceph-authtool /etc/ceph/ceph.keyring --import-keyring /etc/ceph/ceph.client.admin.keyring
+
+
+Create a User
+-------------
+
+Ceph provides the `Add a User`_ function to create a user directly in the Ceph
+Storage Cluster. However, you can also create a user, keys and capabilities
+directly on a Ceph client keyring. Then, you can import the user to the Ceph
+Storage Cluster. For example::
+
+ sudo ceph-authtool -n client.ringo --cap osd 'allow rwx' --cap mon 'allow rwx' /etc/ceph/ceph.keyring
+
+See `Authorization (Capabilities)`_ for additional details on capabilities.
+
+You can also create a keyring and add a new user to the keyring simultaneously.
+For example::
+
+ sudo ceph-authtool -C /etc/ceph/ceph.keyring -n client.ringo --cap osd 'allow rwx' --cap mon 'allow rwx' --gen-key
+
+In the foregoing scenarios, the new user ``client.ringo`` is only in the
+keyring. To add the new user to the Ceph Storage Cluster, you must still add
+the new user to the Ceph Storage Cluster. ::
+
+ sudo ceph auth add client.ringo -i /etc/ceph/ceph.keyring
+
+
+Modify a User
+-------------
+
+To modify the capabilities of a user record in a keyring, specify the keyring,
+and the user followed by the capabilities. For example::
+
+ sudo ceph-authtool /etc/ceph/ceph.keyring -n client.ringo --cap osd 'allow rwx' --cap mon 'allow rwx'
+
+To update the user to the Ceph Storage Cluster, you must update the user
+in the keyring to the user entry in the the Ceph Storage Cluster. ::
+
+ sudo ceph auth import -i /etc/ceph/ceph.keyring
+
+See `Import a User(s)`_ for details on updating a Ceph Storage Cluster user
+from a keyring.
+
+You may also `Modify User Capabilities`_ directly in the cluster, store the
+results to a keyring file; then, import the keyring into your main
+``ceph.keyring`` file.
+
+
+Command Line Usage
+==================
+
+Ceph supports the following usage for user name and secret:
+
+``--id`` | ``--user``
+
+:Description: Ceph identifies users with a type and an ID (e.g., ``TYPE.ID`` or
+ ``client.admin``, ``client.user1``). The ``id``, ``name`` and
+ ``-n`` options enable you to specify the ID portion of the user
+ name (e.g., ``admin``, ``user1``, ``foo``, etc.). You can specify
+ the user with the ``--id`` and omit the type. For example,
+ to specify user ``client.foo`` enter the following::
+
+ ceph --id foo --keyring /path/to/keyring health
+ ceph --user foo --keyring /path/to/keyring health
+
+
+``--name`` | ``-n``
+
+:Description: Ceph identifies users with a type and an ID (e.g., ``TYPE.ID`` or
+ ``client.admin``, ``client.user1``). The ``--name`` and ``-n``
+ options enables you to specify the fully qualified user name.
+ You must specify the user type (typically ``client``) with the
+ user ID. For example::
+
+ ceph --name client.foo --keyring /path/to/keyring health
+ ceph -n client.foo --keyring /path/to/keyring health
+
+
+``--keyring``
+
+:Description: The path to the keyring containing one or more user name and
+ secret. The ``--secret`` option provides the same functionality,
+ but it does not work with Ceph RADOS Gateway, which uses
+ ``--secret`` for another purpose. You may retrieve a keyring with
+ ``ceph auth get-or-create`` and store it locally. This is a
+ preferred approach, because you can switch user names without
+ switching the keyring path. For example::
+
+ sudo rbd map --id foo --keyring /path/to/keyring mypool/myimage
+
+
+.. _pools: ../pools
+
+
+Limitations
+===========
+
+The ``cephx`` protocol authenticates Ceph clients and servers to each other. It
+is not intended to handle authentication of human users or application programs
+run on their behalf. If that effect is required to handle your access control
+needs, you must have another mechanism, which is likely to be specific to the
+front end used to access the Ceph object store. This other mechanism has the
+role of ensuring that only acceptable users and programs are able to run on the
+machine that Ceph will permit to access its object store.
+
+The keys used to authenticate Ceph clients and servers are typically stored in
+a plain text file with appropriate permissions in a trusted host.
+
+.. important:: Storing keys in plaintext files has security shortcomings, but
+ they are difficult to avoid, given the basic authentication methods Ceph
+ uses in the background. Those setting up Ceph systems should be aware of
+ these shortcomings.
+
+In particular, arbitrary user machines, especially portable machines, should not
+be configured to interact directly with Ceph, since that mode of use would
+require the storage of a plaintext authentication key on an insecure machine.
+Anyone who stole that machine or obtained surreptitious access to it could
+obtain the key that will allow them to authenticate their own machines to Ceph.
+
+Rather than permitting potentially insecure machines to access a Ceph object
+store directly, users should be required to sign in to a trusted machine in
+your environment using a method that provides sufficient security for your
+purposes. That trusted machine will store the plaintext Ceph keys for the
+human users. A future version of Ceph may address these particular
+authentication issues more fully.
+
+At the moment, none of the Ceph authentication protocols provide secrecy for
+messages in transit. Thus, an eavesdropper on the wire can hear and understand
+all data sent between clients and servers in Ceph, even if it cannot create or
+alter them. Further, Ceph does not include options to encrypt user data in the
+object store. Users can hand-encrypt and store their own data in the Ceph
+object store, of course, but Ceph provides no features to perform object
+encryption itself. Those storing sensitive data in Ceph should consider
+encrypting their data before providing it to the Ceph system.
+
+
+.. _Architecture - High Availability Authentication: ../../../architecture#high-availability-authentication
+.. _Cephx Config Reference: ../../configuration/auth-config-ref