..
      Copyright 2011 OpenStack Foundation
      All Rights Reserved.

      Licensed under the Apache License, Version 2.0 (the "License"); you may
      not use this file except in compliance with the License. You may obtain
      a copy of the License at

          http://www.apache.org/licenses/LICENSE-2.0

      Unless required by applicable law or agreed to in writing, software
      distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
      WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
      License for the specific language governing permissions and limitations
      under the License.

.. _basic-configuration:

Basic Configuration
===================

Glance has a number of options that you can use to configure the Glance API
server and the various storage backends that Glance can use to store images.

Most configuration is done via configuration files.

When starting up a Glance server, you can specify the configuration file to
use (see :ref:`the documentation on controller Glance servers
<controlling-servers>`). If you do **not** specify a configuration file,
Glance will look in the following directories for a configuration file,
in order:

* ``~/.glance``
* ``~/``
* ``/etc/glance``
* ``/etc``

The Glance API server configuration file should be named ``glance-api.conf``.
There are many other configuration files also since Glance maintains a
configuration file for each of its services. If you installed Glance via your
operating system's package management system, it is likely that you will have
sample configuration files installed in ``/etc/glance``.

In addition, sample configuration files for each server application with
detailed comments are available in the :ref:`Glance Sample Configuration
<sample-configuration>` section.

The PasteDeploy configuration (controlling the deployment of the WSGI
application for each component) may be found by default in
<component>-paste.ini alongside the main configuration file, <component>.conf.
For example, ``glance-api-paste.ini`` corresponds to ``glance-api.conf``.
This pathname for the paste config is configurable, as follows::

  [paste_deploy]
  config_file = /path/to/paste/config


Common Configuration Options in Glance
--------------------------------------

Glance has a few command-line options that are common to all Glance programs:

``--verbose``
  Optional. Default: ``False``

  Can be specified on the command line and in configuration files.

  Turns on the INFO level in logging and prints more verbose command-line
  interface printouts.

``--debug``
  Optional. Default: ``False``

  Can be specified on the command line and in configuration files.

  Turns on the DEBUG level in logging.

``--config-file=PATH``
  Optional. Default: See below for default search order.

  Specified on the command line only.

  Takes a path to a configuration file to use when running the program. If this
  CLI option is not specified, then we check to see if the first argument is a
  file. If it is, then we try to use that as the configuration file.
  If there is no file or there were no arguments, we search for a configuration
  file in the following order:

  * ``~/.glance``
  * ``~/``
  * ``/etc/glance``
  * ``/etc``

  The filename that is searched for depends on the server application name. So,
  if you are starting up the API server, ``glance-api.conf`` is searched for.

``--config-dir=DIR``
  Optional. Default: ``None``

  Specified on the command line only.

  Takes a path to a configuration directory from which all \*.conf fragments
  are loaded. This provides an alternative to multiple ``--config-file``
  options when it is inconvenient to explicitly enumerate all the
  configuration files, for example when an unknown number of config fragments
  are being generated by a deployment framework.

  If ``--config-dir`` is set, then ``--config-file`` is ignored.

  An example usage would be::

    $ glance-api --config-dir=/etc/glance/glance-api.d

    $ ls /etc/glance/glance-api.d
      00-core.conf
      01-swift.conf
      02-ssl.conf
      ... etc.

  The numeric prefixes in the example above are only necessary if a specific
  parse ordering is required (i.e. if an individual config option set in an
  earlier fragment is overridden in a later fragment).

  Note that ``glance-manage`` currently loads configuration from three files:

  * ``glance-api.conf``
  * ``glance-manage.conf``

  By default ``glance-manage.conf`` only specifies a custom logging file but
  other configuration options for ``glance-manage`` should be migrated
  in there.
  **Warning**: Options set in ``glance-manage.conf`` will override options of
  the same section and name set in ``glance-api.conf``

Configuring Server Startup Options
----------------------------------

You can put the following options in the ``glance-api.conf`` file, under
the ``[DEFAULT]`` section. They enable startup and binding behaviour for
the API servers, respectively.

``bind_host=ADDRESS``
  The address of the host to bind to.

  Optional. Default: ``0.0.0.0``

``bind_port=PORT``
  The port the server should bind to.

  Optional. Default: ``9292`` for the API server

``backlog=REQUESTS``
  Number of backlog requests to configure the socket with.

  Optional. Default: ``4096``

``tcp_keepidle=SECONDS``
  Sets the value of TCP_KEEPIDLE in seconds for each server socket.
  Not supported on OS X.

  Optional. Default: ``600``

``client_socket_timeout=SECONDS``
  Timeout for client connections' socket operations.  If an incoming
  connection is idle for this period it will be closed.  A value of `0`
  means wait forever.

  Optional. Default: ``900``

``workers=PROCESSES``
  Number of Glance API worker processes to start. Each worker process will
  listen on the same port. Increasing this value may increase performance
  (especially if using SSL with compression enabled). Typically it is
  recommended to have one worker process per CPU. The value `0` will prevent
  any new worker processes from being created. When ``data_api`` is set to
  ``glance.db.simple.api``, ``workers`` MUST be set to either ``0`` or ``1``.

  Optional. Default: The number of CPUs available will be used by default.

``max_request_id_length=LENGTH``
  Limits the maximum size of the x-openstack-request-id header which is
  logged. Affects only if context middleware is configured in pipeline.

  Optional. Default: ``64`` (Limited by max_header_line default: 16384)

Configuring Logging in Glance
-----------------------------

There are a number of configuration options in Glance that control how Glance
servers log messages.

``--log-config=PATH``
  Optional. Default: ``None``

  Specified on the command line only.

  Takes a path to a configuration file to use for configuring logging.

Logging Options Available Only in Configuration Files
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You will want to place the different logging options in the **[DEFAULT]**
section in your application configuration file. As an example, you might
do the following for the API server, in a configuration file called
``etc/glance-api.conf``::

  [DEFAULT]
  log_file = /var/log/glance/api.log

``log_file``
  The filepath of the file to use for logging messages from Glance's servers.
  If missing, the default is to output messages to ``stdout``,
  so if you are running Glance servers in a daemon mode
  (using ``glance-control``) you should make sure that the ``log_file``
  option is set appropriately.

``log_dir``
  The filepath of the directory to use for log files.
  If not specified (the default) the ``log_file`` is used as
  an absolute filepath.

``log_date_format``
  The format string for timestamps in the log output.

  Defaults to ``%Y-%m-%d %H:%M:%S``. See the
  `logging module <http://docs.python.org/library/logging.html>`_
  documentation for more information on setting this format string.

``log_use_syslog``
  Use syslog logging functionality.

  Defaults to False.

Configuring Glance Storage Backends
-----------------------------------

There are a number of configuration options in Glance that control how Glance
stores disk images. These configuration options are specified in the
``glance-api.conf`` configuration file in the section ``[glance_store]``.

``default_store=STORE``
  Optional. Default: ``file``

  Can only be specified in configuration files.

  Sets the storage backend to use by default when storing images in Glance.
  Available options for this option are (``file``, ``swift``, ``rbd``,
  ``cinder`` or ``vsphere``). In order to select a default store it must also
  be listed in the ``stores`` list described below.

``stores=STORES``
  Optional. Default: ``file, http``

  A comma separated list of enabled glance stores. Some available options for
  this option are (``filesystem``, ``http``, ``rbd``, ``swift``, ``cinder``,
  ``vmware``)

Configuring the Filesystem Storage Backend
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

``filesystem_store_datadir=PATH``
  Optional. Default: ``/var/lib/glance/images/``

  Can only be specified in configuration files.

  `This option is specific to the filesystem storage backend.`

  Sets the path where the filesystem storage backend write disk images.
  Note that the filesystem storage backend will attempt to create this
  directory if it does not exist. Ensure that the user that ``glance-api``
  runs under has write permissions to this directory.

``filesystem_store_file_perm=PERM_MODE``
  Optional. Default: ``0``

  Can only be specified in configuration files.

  `This option is specific to the filesystem storage backend.`

  The required permission value, in octal representation, for the created
  image file. You can use this value to specify the user of the consuming
  service (such as Nova) as the only member of the group that owns
  the created files. To keep the default value, assign a permission value that
  is less than or equal to 0.  Note that the file owner must maintain read
  permission; if this value removes that permission an error message
  will be logged and the BadStoreConfiguration exception will be raised.
  If the Glance service has insufficient privileges to change file access
  permissions, a file will still be saved, but a warning message
  will appear in the Glance log.

``filesystem_store_chunk_size=SIZE_IN_BYTES``
  Optional. Default: ``65536``

  Can only be specified in configuration files.

  `This option is specific to the filesystem storage backend.`

  The chunk size used when reading or writing image files. Raising this value
  may improve the throughput but it may also slightly increase the memory
  usage when handling a large number of requests.

Configuring the Filesystem Storage Backend with multiple stores
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

``filesystem_store_datadirs=PATH:PRIORITY``
  Optional. Default: ``/var/lib/glance/images/:1``

  Example::

    filesystem_store_datadirs = /var/glance/store
    filesystem_store_datadirs = /var/glance/store1:100
    filesystem_store_datadirs = /var/glance/store2:200

  This option can only be specified in configuration file and is specific
  to the filesystem storage backend only.

  filesystem_store_datadirs option allows administrators to configure
  multiple store directories to save glance image in filesystem storage
  backend. Each directory can be coupled with its priority.

  **NOTE**:

  * This option can be specified multiple times to specify multiple stores.
  * Either filesystem_store_datadir or filesystem_store_datadirs option must be
    specified in glance-api.conf
  * Store with priority 200 has precedence over store with priority 100.
  * If no priority is specified, default priority '0' is associated with it.
  * If two filesystem stores have same priority store with maximum free space
    will be chosen to store the image.
  * If same store is specified multiple times then BadStoreConfiguration
    exception will be raised.

Configuring the Swift Storage Backend
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

``swift_store_auth_address=URL``
  Required when using the Swift storage backend.

  Can only be specified in configuration files.

  Deprecated. Use ``auth_address`` in the Swift back-end configuration
  file instead.

  `This option is specific to the Swift storage backend.`

  Sets the authentication URL supplied to Swift when making calls to its
  storage system. For more information about the Swift authentication system,
  please see the
  `Swift auth <https://docs.openstack.org/swift/latest/overview_auth.html>`_
  documentation.

  **IMPORTANT NOTE**: Swift authentication addresses use HTTPS by default. This
  means that if you are running Swift with authentication over HTTP, you need
  to set your ``swift_store_auth_address`` to the full URL,
  including the ``http://``.

``swift_store_user=USER``
  Required when using the Swift storage backend.

  Can only be specified in configuration files.

  Deprecated. Use ``user`` in the Swift back-end configuration file instead.

  `This option is specific to the Swift storage backend.`

  Sets the user to authenticate against the ``swift_store_auth_address`` with.

``swift_store_key=KEY``
  Required when using the Swift storage backend.

  Can only be specified in configuration files.

  Deprecated. Use ``key`` in the Swift back-end configuration file instead.

  `This option is specific to the Swift storage backend.`

  Sets the authentication key to authenticate against the
  ``swift_store_auth_address`` with for the user ``swift_store_user``.

``swift_store_container=CONTAINER``
  Optional. Default: ``glance``

  Can only be specified in configuration files.

  `This option is specific to the Swift storage backend.`

  Sets the name of the container to use for Glance images in Swift.

``swift_store_create_container_on_put``
  Optional. Default: ``False``

  Can only be specified in configuration files.

  `This option is specific to the Swift storage backend.`

  If true, Glance will attempt to create the container
  ``swift_store_container`` if it does not exist.

``swift_store_large_object_size=SIZE_IN_MB``
  Optional. Default: ``5120``

  Can only be specified in configuration files.

  `This option is specific to the Swift storage backend.`

  What size, in MB, should Glance start chunking image files
  and do a large object manifest in Swift? By default, this is
  the maximum object size in Swift, which is 5GB

``swift_store_large_object_chunk_size=SIZE_IN_MB``
  Optional. Default: ``200``

  Can only be specified in configuration files.

  `This option is specific to the Swift storage backend.`

  When doing a large object manifest, what size, in MB, should
  Glance write chunks to Swift?  The default is 200MB.

``swift_store_multi_tenant=False``
  Optional. Default: ``False``

  Can only be specified in configuration files.

  `This option is specific to the Swift storage backend.`

  If set to True enables multi-tenant storage mode which causes Glance images
  to be stored in tenant specific Swift accounts. When set to False Glance
  stores all images in a single Swift account.

``swift_store_multiple_containers_seed``
  Optional. Default: ``0``

  Can only be specified in configuration files.

  `This option is specific to the Swift storage backend.`

  When set to 0, a single-tenant store will only use one container to store all
  images. When set to an integer value between 1 and 32, a single-tenant store
  will use multiple containers to store images, and this value will determine
  how many characters from an image UUID are checked when determining what
  container to place the image in. The maximum number of containers that will
  be created is approximately equal to 16^N. This setting is used only when
  swift_store_multi_tenant is disabled.

  Example: if this config option is set to 3 and
  swift_store_container = 'glance', then an image with UUID
  'fdae39a1-bac5-4238-aba4-69bcc726e848' would be placed in the container
  'glance_fda'. All dashes in the UUID are included when creating the container
  name but do not count toward the character limit, so in this example
  with N=10 the container name would be 'glance_fdae39a1-ba'.

  When choosing the value for swift_store_multiple_containers_seed, deployers
  should discuss a suitable value with their swift operations team. The authors
  of this option recommend that large scale deployments use a value of '2',
  which will create a maximum of ~256 containers. Choosing a higher number than
  this, even in extremely large scale deployments, may not have any positive
  impact on performance and could lead to a large number of empty, unused
  containers. The largest of deployments could notice an increase in
  performance if swift rate limits are throttling on single container.
  Note: If dynamic container creation is turned off, any value for this
  configuration option higher than '1' may be unreasonable as the deployer
  would have to manually create each container.

``swift_store_admin_tenants``
  Can only be specified in configuration files.

  `This option is specific to the Swift storage backend.`

  Optional. Default: Not set.

  A list of swift ACL strings that will be applied as both read and
  write ACLs to the containers created by Glance in multi-tenant
  mode. This grants the specified tenants/users read and write access
  to all newly created image objects. The standard swift ACL string
  formats are allowed, including:

  <tenant_id>:<username>
  <tenant_name>:<username>
  \*:<username>

  Multiple ACLs can be combined using a comma separated list, for
  example: swift_store_admin_tenants = service:glance,*:admin

``swift_store_auth_version``
  Can only be specified in configuration files.

  Deprecated. Use ``auth_version`` in the Swift back-end configuration
  file instead.

  `This option is specific to the Swift storage backend.`

  Optional. Default: ``2``

  A string indicating which version of Swift OpenStack authentication
  to use. See the project
  `python-swiftclient <https://docs.openstack.org/python-swiftclient/latest/>`_
  for more details.

``swift_store_service_type``
  Can only be specified in configuration files.

  `This option is specific to the Swift storage backend.`

  Optional. Default: ``object-store``

  A string giving the service type of the swift service to use. This
  setting is only used if swift_store_auth_version is ``2``.

``swift_store_region``
  Can only be specified in configuration files.

  `This option is specific to the Swift storage backend.`

  Optional. Default: Not set.

  A string giving the region of the swift service endpoint to use. This
  setting is only used if swift_store_auth_version is ``2``. This
  setting is especially useful for disambiguation if multiple swift
  services might appear in a service catalog during authentication.

``swift_store_endpoint_type``
  Can only be specified in configuration files.

  `This option is specific to the Swift storage backend.`

  Optional. Default: ``publicURL``

  A string giving the endpoint type of the swift service endpoint to
  use. This setting is only used if swift_store_auth_version is ``2``.

``swift_store_ssl_compression``
  Can only be specified in configuration files.

  `This option is specific to the Swift storage backend.`

  Optional. Default: True.

  If set to False, disables SSL layer compression of https swift
  requests. Setting to 'False' may improve performance for images which
  are already in a compressed format, e.g. qcow2. If set to True then
  compression will be enabled (provided it is supported by the swift
  proxy).

``swift_store_cacert``
  Can only be specified in configuration files.

  Optional. Default: ``None``

  A string giving the path to a CA certificate bundle that will allow Glance's
  services to perform SSL verification when communicating with Swift.

``swift_store_retry_get_count``
  The number of times a Swift download will be retried before the request
  fails.
  Optional. Default: ``0``

Configuring Multiple Swift Accounts/Stores
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

In order to not store Swift account credentials in the database, and to
have support for multiple accounts (or multiple Swift backing stores), a
reference is stored in the database and the corresponding configuration
(credentials/ parameters) details are stored in the configuration file.
Optional.  Default: not enabled.

The location for this file is specified using the ``swift_store_config_file``
configuration file in the section ``[DEFAULT]``. **If an incorrect value is
specified, Glance API Swift store service will not be configured.**

``swift_store_config_file=PATH``
  `This option is specific to the Swift storage backend.`

``default_swift_reference=DEFAULT_REFERENCE``
  Required when multiple Swift accounts/backing stores are configured.

  Can only be specified in configuration files.

  `This option is specific to the Swift storage backend.`

  It is the default swift reference that is used to add any new images.

``swift_store_auth_insecure``
  If True, bypass SSL certificate verification for Swift.

  Can only be specified in configuration files.

  `This option is specific to the Swift storage backend.`

  Optional. Default: ``False``

Configuring Swift configuration file
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

If ``swift_store_config_file`` is set, Glance will use information
from the file specified under this parameter.

.. note::
   The ``swift_store_config_file`` is currently used only for single-tenant
   Swift store configurations. If you configure a multi-tenant Swift store
   back end (``swift_store_multi_tenant=True``), ensure that both
   ``swift_store_config_file`` and ``default_swift_reference`` are *not* set.

The file contains a set of references like:

.. code-block:: ini

    [ref1]
    user = tenant:user1
    key = key1
    auth_version = 2
    auth_address = http://localhost:5000/v2.0

    [ref2]
    user = project_name:user_name2
    key = key2
    user_domain_id = default
    project_domain_id = default
    auth_version = 3
    auth_address = http://localhost:5000/v3

A default reference must be configured. Its parameters will be used when
creating new images. For example, to specify ``ref2`` as the default
reference, add the following value to the [glance_store] section of
:file:`glance-api.conf` file:

.. code-block:: ini

    default_swift_reference = ref2

In the reference, a user can specify the following parameters:

``user``
  A *project_name user_name* pair in the ``project_name:user_name`` format
  to authenticate against the Swift authentication service.

``key``
  An authentication key for a user authenticating against the Swift
  authentication service.

``auth_address``
  An address where the Swift authentication service is located.

``auth_version``
  A version of the authentication service to use.
  Valid versions are ``2`` and ``3`` for Keystone and ``1``
  (deprecated) for Swauth and Rackspace.

  Optional. Default: ``2``

``project_domain_id``
  A domain ID of the project which is the requested project-level
  authorization scope.

  Optional. Default: ``None``

  `This option can be specified if ``auth_version`` is ``3`` .`

``project_domain_name``
  A domain name of the project which is the requested project-level
  authorization scope.

  Optional. Default: ``None``

  `This option can be specified if ``auth_version`` is ``3`` .`

``user_domain_id``
  A domain ID of the user which is the requested domain-level
  authorization scope.

  Optional. Default: ``None``

  `This option can be specified if ``auth_version`` is ``3`` .`

``user_domain_name``
  A domain name of the user which is the requested domain-level
  authorization scope.

  Optional. Default: ``None``

  `This option can be specified if ``auth_version`` is ``3``. `

Configuring the RBD Storage Backend
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

**Note**: the RBD storage backend requires the python bindings for
librados and librbd. These are in the python-ceph package on
Debian-based distributions.

``rbd_store_pool=POOL``
  Optional. Default: ``rbd``

  Can only be specified in configuration files.

  `This option is specific to the RBD storage backend.`

  Sets the RADOS pool in which images are stored.

``rbd_store_chunk_size=CHUNK_SIZE_MB``
  Optional. Default: ``4``

  Can only be specified in configuration files.

  `This option is specific to the RBD storage backend.`

  Images will be chunked into objects of this size (in megabytes).
  For best performance, this should be a power of two.

``rados_connect_timeout``
  Optional. Default: ``0``

  Can only be specified in configuration files.

  `This option is specific to the RBD storage backend.`

  Prevents glance-api hangups during the connection to RBD. Sets the time
  to wait (in seconds) for glance-api before closing the connection.
  Setting ``rados_connect_timeout<=0`` means no timeout.

``rbd_store_ceph_conf=PATH``
  Optional. Default: ``/etc/ceph/ceph.conf``, ``~/.ceph/config``, and
  ``./ceph.conf``

  Can only be specified in configuration files.

  `This option is specific to the RBD storage backend.`

  Sets the Ceph configuration file to use.

``rbd_store_user=NAME``
  Optional. Default: ``admin``

  Can only be specified in configuration files.

  `This option is specific to the RBD storage backend.`

  Sets the RADOS user to authenticate as. This is only needed
  when `RADOS authentication <https://docs.ceph.com/docs/emperor/rados/operations/authentication/>`_
  is `enabled.
  <https://docs.ceph.com/docs/emperor/rados/operations/authentication/#enabling-cephx>`_

A keyring must be set for this user in the Ceph
configuration file, e.g. with a user ``glance``::

  [client.glance]
  keyring=/etc/glance/rbd.keyring

To set up a user named ``glance`` with minimal permissions,
using a pool called ``images``, run::

  rados mkpool images
  ceph-authtool --create-keyring /etc/glance/rbd.keyring
  ceph-authtool --gen-key --name client.glance --cap mon 'allow r' --cap osd 'allow rwx pool=images' /etc/glance/rbd.keyring
  ceph auth add client.glance -i /etc/glance/rbd.keyring

Configuring the Cinder Storage Backend
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

**Note**: To create a Cinder volume from an image in this store quickly, additional
settings are required. Please see the
`Volume-backed image <https://docs.openstack.org/cinder/latest/admin/blockstorage-volume-backed-image.html>`_
documentation for more information.

``cinder_catalog_info=<service_type>:<service_name>:<endpoint_type>``
  Optional. Default: ``volumev2::publicURL``

  Can only be specified in configuration files.

  `This option is specific to the Cinder storage backend.`

  Sets the info to match when looking for cinder in the service catalog.
  Format is :
  separated values of the form: <service_type>:<service_name>:<endpoint_type>

``cinder_endpoint_template=http://ADDR:PORT/VERSION/%(tenant)s``
  Optional. Default: ``None``

  Can only be specified in configuration files.

  `This option is specific to the Cinder storage backend.`

  Override service catalog lookup with template for cinder endpoint.
  ``%(...)s`` parts are replaced by the value in the request context.
  e.g. http://localhost:8776/v2/%(tenant)s

``os_region_name=REGION_NAME``
  Optional. Default: ``None``

  Can only be specified in configuration files.

  `This option is specific to the Cinder storage backend.`

  Region name of this node.

  Deprecated. Use ``cinder_os_region_name`` instead.

``cinder_os_region_name=REGION_NAME``
  Optional. Default: ``None``

  Can only be specified in configuration files.

  `This option is specific to the Cinder storage backend.`

  Region name of this node.  If specified, it is used to locate cinder from
  the service catalog.

``cinder_ca_certificates_file=CA_FILE_PATH``
  Optional. Default: ``None``

  Can only be specified in configuration files.

  `This option is specific to the Cinder storage backend.`

  Location of ca certificates file to use for cinder client requests.

``cinder_http_retries=TIMES``
  Optional. Default: ``3``

  Can only be specified in configuration files.

  `This option is specific to the Cinder storage backend.`

  Number of cinderclient retries on failed http calls.

``cinder_state_transition_timeout``
  Optional. Default: ``300``

  Can only be specified in configuration files.

  `This option is specific to the Cinder storage backend.`

  Time period, in seconds, to wait for a cinder volume transition to complete.

``cinder_api_insecure=ON_OFF``
  Optional. Default: ``False``

  Can only be specified in configuration files.

  `This option is specific to the Cinder storage backend.`

  Allow to perform insecure SSL requests to cinder.

``cinder_store_user_name=NAME``
  Optional. Default: ``None``

  Can only be specified in configuration files.

  `This option is specific to the Cinder storage backend.`

  User name to authenticate against Cinder. If <None>, the user of current
  context is used.

  **NOTE**: This option is applied only if all of ``cinder_store_user_name``,
  ``cinder_store_password``, ``cinder_store_project_name`` and
  ``cinder_store_auth_address`` are set.
  These options are useful to put image volumes into the internal service
  project in order to hide the volume from users, and to make the image
  shareable among projects.

``cinder_store_password=PASSWORD``
  Optional. Default: ``None``

  Can only be specified in configuration files.

  `This option is specific to the Cinder storage backend.`

  Password for the user authenticating against Cinder. If <None>, the current
  context auth token is used.

``cinder_store_project_name=NAME``
  Optional. Default: ``None``

  Can only be specified in configuration files.

  `This option is specific to the Cinder storage backend.`

  Project name where the image is stored in Cinder. If <None>, the project
  in current context is used.

``cinder_store_auth_address=URL``
  Optional. Default: ``None``

  Can only be specified in configuration files.

  `This option is specific to the Cinder storage backend.`

  The address where the Cinder authentication service is listening. If <None>,
  the cinder endpoint in the service catalog is used.

``rootwrap_config=NAME``
  Optional. Default: ``/etc/glance/rootwrap.conf``

  Can only be specified in configuration files.

  `This option is specific to the Cinder storage backend.`

  Path to the rootwrap configuration file to use for running commands as root.

Configuring multiple Cinder Storage Backend
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

From Victoria onwards Glance fully supports configuring multiple cinder
backends and user/operator will decide which cinder backend to use. While
using cinder as a store for glance, operator may configure which volume
types to used by setting the ``enabled_backends`` configuration option in
``glance-api.conf``. For each of the stores defined in ``enabled_backends``
administrator has to set specific ``volume_type`` using
``cinder_volume_type`` configuration option in its own config section.

**NOTE** Even in cinder one backend can be associated with multiple
volume type(s), glance will support only one store per cinder volume type.

Below are some multiple cinder store configuration examples.

Example 1: Fresh deployment

For example, if cinder has configured 2 volume types `fast` and `slow` then
glance configuration should look like;::

    [DEFAULT]
    # list of enabled stores identified by their property group name
    enabled_backends = fast:cinder, slow:cinder

    # the default store, if not set glance-api service will not start
    [glance_store]
    default_backend = fast

    # conf props for fast store instance
    [fast]
    rootwrap_config = /etc/glance/rootwrap.conf
    cinder_volume_type = glance-fast
    description = LVM based cinder store
    cinder_catalog_info = volumev2::publicURL
    cinder_store_auth_address = http://localhost/identity/v3
    cinder_store_user_name = glance
    cinder_store_password = admin
    cinder_store_project_name = service
    # etc..

    # conf props for slow store instance
    [slow]
    rootwrap_config = /etc/glance/rootwrap.conf
    cinder_volume_type = glance-slow
    description = NFS based cinder store
    cinder_catalog_info = volumev2::publicURL
    cinder_store_auth_address = http://localhost/identity/v3
    cinder_store_user_name = glance
    cinder_store_password = admin
    cinder_store_project_name = service
    # etc..

Example 2: Upgrade from single cinder store to multiple cinder stores, if
`default_volume_type` is set in `cinder.conf` and `cinder_volume_type` is
also set in `glance-api.conf` then operator needs to create one store in
glance where `cinder_volume_type` is same as the old glance configuration::

    # cinder.conf
    The glance administrator has to find out what the default volume-type is
    in the cinder installation, so they need to discuss with either cinder
    admin or cloud admin to identify default volume-type from cinder and then
    explicitly configure that as the value of ``cinder_volume_type``.

Example config before upgrade::

    # old configuration in glance
    [glance_store]
    stores = cinder, file, http
    default_store = cinder
    cinder_state_transition_timeout = 300
    rootwrap_config = /etc/glance/rootwrap.conf
    cinder_catalog_info = volumev2::publicURL
    cinder_volume_type = glance-old

Example config after upgrade::

    # new configuration in glance
    [DEFAULT]
    enabled_backends = old:cinder, new:cinder

    [glance_store]
    default_backend = new

    [new]
    rootwrap_config = /etc/glance/rootwrap.conf
    cinder_volume_type = glance-new
    description = LVM based cinder store
    cinder_catalog_info = volumev2::publicURL
    cinder_store_auth_address = http://localhost/identity/v3
    cinder_store_user_name = glance
    cinder_store_password = admin
    cinder_store_project_name = service
    # etc..

    [old]
    rootwrap_config = /etc/glance/rootwrap.conf
    cinder_volume_type = glance-old # as per old cinder.conf
    description = NFS based cinder store
    cinder_catalog_info = volumev2::publicURL
    cinder_store_auth_address = http://localhost/identity/v3
    cinder_store_user_name = glance
    cinder_store_password = admin
    cinder_store_project_name = service
    # etc..

Example 3: Upgrade from single cinder store to multiple cinder stores, if
`default_volume_type` is not set in `cinder.conf` neither `cinder_volume_type`
set in `glance-api.conf` then administrator needs to create one store in
glance to replicate exact old configuration::

    # cinder.conf
    The glance administrator has to find out what the default volume-type is
    in the cinder installation, so they need to discuss with either cinder
    admin or cloud admin to identify default volume-type from cinder and then
    explicitly configure that as the value of ``cinder_volume_type``.

Example config before upgrade::

    # old configuration in glance
    [glance_store]
    stores = cinder, file, http
    default_store = cinder
    cinder_state_transition_timeout = 300
    rootwrap_config = /etc/glance/rootwrap.conf
    cinder_catalog_info = volumev2::publicURL

Example config after upgrade::

    # new configuration in glance
    [DEFAULT]
    enabled_backends = old:cinder, new:cinder

    [glance_store]
    default_backend = new

    # cinder store as per old (single store configuration)
    [old]
    rootwrap_config = /etc/glance/rootwrap.conf
    description = LVM based cinder store
    cinder_catalog_info = volumev2::publicURL
    cinder_store_auth_address = http://localhost/identity/v3
    cinder_store_user_name = glance
    cinder_store_password = admin
    cinder_store_project_name = service
    # etc..

    [new]
    rootwrap_config = /etc/glance/rootwrap.conf
    cinder_volume_type = glance-new
    description = NFS based cinder store
    cinder_catalog_info = volumev2::publicURL
    cinder_store_auth_address = http://localhost/identity/v3
    cinder_store_user_name = glance
    cinder_store_password = admin
    cinder_store_project_name = service
    # etc..

Example 4: Upgrade from single cinder store to multiple cinder stores, if
`default_volume_type` is set in `cinder.conf` but `cinder_volume_type` is
not set in `glance-api.conf` then administrator needs to set
`cinder_volume_type` same as the `default_backend` set in `cinder.conf` to
one of the store::

    # cinder.conf
    The glance administrator has to find out what the default volume-type is
    in the cinder installation, so they need to discuss with either cinder
    admin or cloud admin to identify default volume-type from cinder and then
    explicitly configure that as the value of ``cinder_volume_type``.

Example config before upgrade::

    # old configuration in glance
    [glance_store]
    stores = cinder, file, http
    default_store = cinder
    cinder_state_transition_timeout = 300
    rootwrap_config = /etc/glance/rootwrap.conf
    cinder_catalog_info = volumev2::publicURL

Example config after upgrade::

    # new configuration in glance
    [DEFAULT]
    enabled_backends = old:cinder,new:cinder

    [glance_store]
    default_backend = old

    [old]
    rootwrap_config = /etc/glance/rootwrap.conf
    cinder_volume_type = glance-old # as per old cinder.conf
    description = LVM based cinder store
    cinder_catalog_info = volumev2::publicURL
    cinder_store_auth_address = http://localhost/identity/v3
    cinder_store_user_name = glance
    cinder_store_password = admin
    cinder_store_project_name = service
    # etc..

    [new]
    rootwrap_config = /etc/glance/rootwrap.conf
    cinder_volume_type = glance-new
    description = NFS based cinder store
    cinder_catalog_info = volumev2::publicURL
    cinder_store_auth_address = http://localhost/identity/v3
    cinder_store_user_name = glance
    cinder_store_password = admin
    cinder_store_project_name = service
    # etc..

While upgrading from single cinder stores to multiple single stores, location
URLs for legacy images will be changed from ``cinder://volume-id`` to
``cinder://store-name/volume-id``.

**Note** After upgrade from single cinder store to use multiple cinder
stores the first ``image-list`` or first ``GET`` or ``image-show`` call for
image will take additional time as we will perform the lazy loading
operation to update legacy image location url to use new image location urls.
Subsequent ``GET`` or ``image-list`` or ``image-show`` calls will perform as
they were performing earlier.

Configuring the VMware Storage Backend
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

``vmware_server_host=ADDRESS``
  Required when using the VMware storage backend.

  Can only be specified in configuration files.

  Sets the address of the ESX/ESXi or vCenter Server target system.
  The address can contain an IP (``127.0.0.1``), an IP and port
  (``127.0.0.1:443``), a DNS name (``www.my-domain.com``) or DNS and port.

  `This option is specific to the VMware storage backend.`

``vmware_server_username=USERNAME``
  Required when using the VMware storage backend.

  Can only be specified in configuration files.

  Username for authenticating with VMware ESX/ESXi or vCenter Server.

``vmware_server_password=PASSWORD``
  Required when using the VMware storage backend.

  Can only be specified in configuration files.

  Password for authenticating with VMware ESX/ESXi or vCenter Server.

``vmware_datastores``
  Required when using the VMware storage backend.

  This option can only be specified in configuration file and is specific
  to the VMware storage backend.

  vmware_datastores allows administrators to configure multiple datastores to
  save glance image in the VMware store backend. The required format for the
  option is: <datacenter_path>:<datastore_name>:<optional_weight>.

  where datacenter_path is the inventory path to the datacenter where the
  datastore is located. An optional weight can be given to specify the
  priority.

  Example::

    vmware_datastores = datacenter1:datastore1
    vmware_datastores = dc_folder/datacenter2:datastore2:100
    vmware_datastores = datacenter1:datastore3:200

  **NOTE**:

  * This option can be specified multiple times to specify multiple datastores.
  * Either vmware_datastore_name or vmware_datastores option must be specified
    in glance-api.conf
  * Datastore with weight 200 has precedence over datastore with weight 100.
  * If no weight is specified, default weight '0' is associated with it.
  * If two datastores have same weight, the datastore with maximum free space
    will be chosen to store the image.
  * If the datacenter path or datastore name contains a colon (:) symbol, it
    must be escaped with a backslash.

``vmware_api_retry_count=TIMES``
  Optional. Default: ``10``

  Can only be specified in configuration files.

  The number of times VMware ESX/VC server API must be
  retried upon connection related issues.

``vmware_task_poll_interval=SECONDS``
  Optional. Default: ``5``

  Can only be specified in configuration files.

  The interval used for polling remote tasks invoked on VMware ESX/VC server.

``vmware_store_image_dir``
  Optional. Default: ``/openstack_glance``

  Can only be specified in configuration files.

  The path to access the folder where the images will be stored
  in the datastore.

``vmware_api_insecure=ON_OFF``
  Optional. Default: ``False``

  Can only be specified in configuration files.

  Allow to perform insecure SSL requests to ESX/VC server.

Configuring the S3 Storage Backend
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

``s3_store_host``
  Can only be specified in configuration files.

  The host where the S3 server is listening. This option can contain a DNS name
  (e.g. s3.amazonaws.com, my-object-storage.com) or an IP address (127.0.0.1).

  Example::

    s3_store_host = http://s3-ap-northeast-1.amazonaws.com
    s3_store_host = https://s3-ap-northeast-1.amazonaws.com
    s3_store_host = http://my-object-storage.com
    s3_store_host = https://my-object-storage.com:9000

``s3_store_access_key``
  Can only be specified in configuration files.

  Access Key for authenticating with the Amazon S3 or S3 compatible storage
  server.

``s3_store_secret_key``
  Can only be specified in configuration files.

  Secret Key for authenticating with the Amazon S3 or S3 compatible storage
  server.

``s3_store_bucket``
  Can only be specified in configuration files.

  Bucket name where the glance images will be stored in the S3.
  If ``s3_store_create_bucket_on_put`` is set to true, it will be created
  automatically even if the bucket does not exist.

``s3_store_create_bucket_on_put``
  Optional. Default: ``False``

  Can only be specified in configuration files.

  Determine whether S3 should create a new bucket. This option takes boolean
  value to indicate whether or not Glance should create new bucket to S3 if it
  does not exist.

``s3_store_bucket_url_format``
  Optional. Default: ``auto``

  Can only be specified in configuration files.

  This option takes access model that is used to specify the address of an
  object in an S3 bucket. You can set the value from ``auto``, ``virtual`` or
  ``path``.

  **NOTE**:

  * In ``path``-style, the endpoint for the object looks like ``https://s3.amazonaws.com/bucket/example.img``.
  * In ``virtual``-style, the endpoint for the object looks like ``https://bucket.s3.amazonaws.com/example.img``.
  * If you do not follow the DNS naming convention in the bucket name, you can
    get objects in the path style, but not in the virtual style.

``s3_store_large_object_size``
  Optional. Default: ``100``

  Can only be specified in configuration files.

  What size, in MB, should S3 start chunking image files and do a multipart
  upload in S3.

``s3_store_large_object_chunk_size``
  Optional. Default: ``10``

  Can only be specified in configuration files.

  What multipart upload part size, in MB, should S3 use when uploading parts.

``s3_store_thread_pools``
  Optional. Default: ``10``

  Can only be specified in configuration files.

  The number of thread pools to perform a multipart upload in S3.

Configuring the Storage Endpoint
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

``swift_store_endpoint=URL``
  Optional. Default: ``None``

  Can only be specified in configuration files.

  Overrides the storage URL returned by auth. The URL should include the
  path up to and excluding the container. The location of an object is
  obtained by appending the container and object to the configured URL.
  e.g. ``https://www.my-domain.com/v1/path_up_to_container``

Configuring Glance Image Size Limit
-----------------------------------

The following configuration option is specified in the
``glance-api.conf`` configuration file in the section ``[DEFAULT]``.

``image_size_cap=SIZE``
  Optional. Default: ``1099511627776`` (1 TB)

  Maximum image size, in bytes, which can be uploaded through
  the Glance API server.

  **IMPORTANT NOTE**: this value should only be increased after careful
  consideration and must be set to a value under 8 EB (9223372036854775808).

Configuring Glance User Storage Quota
-------------------------------------

The following configuration option is specified in the
``glance-api.conf`` configuration file in the section ``[DEFAULT]``.

.. note::

   As of the Xena release, Glance supports :ref:`per-tenant <config-per-tenant-quotas>`
   quotas with more granularity than the global limit provided by this
   option. You may want to enable per-tenant quotas and leave this
   unset.

``user_storage_quota``
  Optional. Default: 0 (Unlimited).

  This value specifies the maximum amount of storage that each user can use
  across all storage systems. Optionally unit can be specified for the value.
  Values are accepted in B, KB, MB, GB or TB which are for Bytes, KiloBytes,
  MegaBytes, GigaBytes and TeraBytes respectively. Default unit is Bytes.

  Example values would be,
      user_storage_quota=20GB


.. _config-per-tenant-quotas:

Configuring Glance Per-Tenant Quotas
------------------------------------

Glance can utilize per-tenant resource limits set in Keystone to
enforce quotas on users. These limits must be registered with defaults
in Keystone, with optional per-tenant overrides, prior to enabling
them in Glance. To instruct glance to use limits in Keystone, set
``[DEFAULT]/use_keystone_limits=True`` in ``glance-api.conf``.

Configuring the Image Cache
---------------------------

Glance API servers can be configured to have a local image cache. Caching of
image files is transparent and happens using a piece of middleware that can
optionally be placed in the server application pipeline.

This pipeline is configured in the PasteDeploy configuration file,
<component>-paste.ini. You should not generally have to edit this file
directly, as it ships with ready-made pipelines for all common deployment
flavors.

Enabling the Image Cache Middleware
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To enable the image cache middleware, the cache middleware must occur in
the application pipeline **after** the appropriate context middleware.

The cache middleware should be in your ``glance-api-paste.ini`` in a section
titled ``[filter:cache]``. It should look like this::

  [filter:cache]
  paste.filter_factory = glance.api.middleware.cache:CacheFilter.factory

A ready-made application pipeline including this filter is defined in
the ``glance-api-paste.ini`` file, looking like so::

  [pipeline:glance-api-caching]
  pipeline = versionnegotiation context cache apiv1app

To enable the above application pipeline, in your main ``glance-api.conf``
configuration file, select the appropriate deployment flavor like so::

  [paste_deploy]
  flavor = caching

Enabling the Image Cache Management Middleware (DEPRECATED)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

There is an optional ``cachemanage`` middleware that allows you to
directly interact with cache images. Use this flavor in place of the
``cache`` flavor in your API configuration file. There are three types you
can chose: ``cachemanagement``, ``keystone+cachemanagement`` and
``trusted-auth+cachemanagement``.::

  [paste_deploy]
  flavor = keystone+cachemanagement

The new cache management endpoints were introduced in Images API v. 2.13.
If cache middleware is configured the new endpoints will be active and
there is no need to use the cachemanagement middleware unless the old
`glance-cache-manage` tooling is desired to be still used.

Configuration Options Affecting the Image Cache
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. note::

  These configuration options must be set in both the glance-cache
  and glance-api configuration files.


One main configuration file option affects the image cache.

``image_cache_dir=PATH``
  Required when image cache middleware is enabled.

  Default: ``/var/lib/glance/image-cache``

  This is the base directory the image cache can write files to.
  Make sure the directory is writable by the user running the
  ``glance-api`` server

``image_cache_driver=DRIVER``
  Optional. Choice of ``sqlite`` or ``xattr``

  Default: ``sqlite``

  The default ``sqlite`` cache driver has no special dependencies, other
  than the ``python-sqlite3`` library, which is installed on virtually
  all operating systems with modern versions of Python. It stores
  information about the cached files in a SQLite database.

  The ``xattr`` cache driver required the ``python-xattr>=0.6.0`` library
  and requires that the filesystem containing ``image_cache_dir`` have
  access times tracked for all files (in other words, the noatime option
  CANNOT be set for that filesystem). In addition, ``user_xattr`` must be
  set on the filesystem's description line in fstab. Because of these
  requirements, the ``xattr`` cache driver is not available on Windows.

``image_cache_sqlite_db=DB_FILE``
  Optional.

  Default: ``cache.db``

  When using the ``sqlite`` cache driver, you can set the name of the database
  that will be used to store the cached images information. The database
  is always contained in the ``image_cache_dir``.

``image_cache_max_size=SIZE``
  Optional.

  Default: ``10737418240`` (10 GB)

  Size, in bytes, that the image cache should be constrained to. Images files
  are cached automatically in the local image cache, even if the writing of
  that image file would put the total cache size over this size. The
  ``glance-cache-pruner`` executable is what prunes the image cache to be equal
  to or less than this value. The ``glance-cache-pruner`` executable is
  designed to be run via cron on a regular basis. See more about this
  executable in :ref:`Controlling the Growth of the Image Cache <image-cache>`

Configuring Notifications
-------------------------

Glance can optionally generate notifications to be logged or sent to a message
queue. The configuration options are specified in the ``glance-api.conf``
configuration file.

``[oslo_messaging_notifications]/driver``
  Optional. Default: ``noop``

  Sets the notification driver used by oslo.messaging. Options include
  ``messaging``, ``messagingv2``, ``log`` and ``routing``.

  **NOTE**
  In M release, the``[DEFAULT]/notification_driver`` option has been
  deprecated in favor of ``[oslo_messaging_notifications]/driver``.

  For more information see :ref:`Glance notifications <notifications>` and
  `oslo.messaging <https://docs.openstack.org/oslo.messaging/latest/>`_.

``[DEFAULT]/disabled_notifications``
  Optional. Default: ``[]``

  List of disabled notifications. A notification can be given either as a
  notification type to disable a single event, or as a notification group
  prefix to disable all events within a group.

  Example: if this config option is set to
  ["image.create", "metadef_namespace"], then "image.create" notification will
  not be sent after image is created and none of the notifications
  for metadefinition namespaces will be sent.

Configuring Glance Property Protections
---------------------------------------

Access to image meta properties may be configured using a
:ref:`Property Protections Configuration file <property-protections>`.  The
location for this file can be specified in the ``glance-api.conf``
configuration file in the section ``[DEFAULT]``. **If an incorrect value is
specified, glance API service will not start.**

``property_protection_file=PATH``
  Optional. Default: not enabled.

  If property_protection_file is set, the file may use either roles or policies
  to specify property protections.

``property_protection_rule_format=<roles|policies>``
  Optional. Default: ``roles``.

Configuring Glance APIs
-----------------------

The glance-api service implements versions 2 of the OpenStack Images API.
Currently there are no options to enable or disable specific API versions.

Configuring Glance Tasks
------------------------

Glance Tasks are implemented only for version 2 of the OpenStack Images API.

The config value ``task_time_to_live`` is used to determine how long a task
would be visible to the user after transitioning to either the ``success`` or
the ``failure`` state.

``task_time_to_live=<Time_in_hours>``
  Optional. Default: ``48``

  The config value ``task_executor`` is used to determine which executor
  should be used by the Glance service to process the task. The currently
  available implementation is: ``taskflow``.

``task_executor=<executor_type>``
  Optional. Default: ``taskflow``

  The ``taskflow`` engine has its own set of configuration options,
  under the ``taskflow_executor`` section, that can be tuned to improve
  the task execution process. Among the available options, you may find
  ``engine_mode`` and ``max_workers``. The former allows for selecting
  an execution model and the available options are ``serial``,
  ``parallel`` and ``worker-based``. The ``max_workers`` option,
  instead, allows for controlling the number of workers that will be
  instantiated per executor instance.

  The default value for the ``engine_mode`` is ``parallel``, whereas
  the default number of ``max_workers`` is ``10``.

Configuring Glance performance profiling
----------------------------------------

Glance supports using osprofiler to trace the performance of each key internal
handling, including RESTful API calling, DB operation and etc.

``Please be aware that Glance performance profiling is currently a work in
progress feature.`` Although, some trace points is available, e.g. API
execution profiling at wsgi main entry and SQL execution profiling at DB
module, the more fine-grained trace point is being worked on.

The config value ``enabled`` is used to determine whether fully enable
profiling feature for glance-api service.

``enabled=<True|False>``
  Optional. Default: ``False``

  There is one more configuration option that needs to be defined to enable
  Glance services profiling. The config value ``hmac_keys`` is used for
  encrypting context data for performance profiling.

``hmac_keys=<secret_key_string>``
  Optional. Default: ``SECRET_KEY``

  **IMPORTANT NOTE**: in order to make profiling work as designed operator
  needs to make those values of HMAC key be consistent for all services
  in their deployment. Without HMAC key the profiling will not be triggered
  even profiling feature is enabled.

  The config value ``trace_sqlalchemy`` is used to determine whether fully
  enable sqlalchemy engine based SQL execution profiling feature for glance-api
  service.

``trace_sqlalchemy=<True|False>``
  Optional. Default: ``False``

Configuring Glance public endpoint
----------------------------------

This setting allows an operator to configure the endpoint URL that will
appear in the Glance "versions" response (that is, the response to
``GET /``\  ).  This can be necessary when the Glance API service is run
behind a proxy because the default endpoint displayed in the versions
response is that of the host actually running the API service.  If
Glance is being run behind a load balancer, for example, direct access
to individual hosts running the Glance API may not be allowed, hence the
load balancer URL would be used for this value.

``public_endpoint=<None|URL>``
  Optional. Default: ``None``

Configuring Glance digest algorithm
-----------------------------------

Digest algorithm that will be used for digital signature. The default
is sha256. Use the command::

  openssl list-message-digest-algorithms

to get the available algorithms supported by the version of OpenSSL on the
platform. Examples are "sha1", "sha256", "sha512", etc. If an invalid
digest algorithm is configured, all digital signature operations will fail and
return a ValueError exception with "No such digest method" error.

``digest_algorithm=<algorithm>``
  Optional. Default: ``sha256``

Configuring http_keepalive option
---------------------------------

``http_keepalive=<True|False>``
  If False, server will return the header "Connection: close", If True, server
  will return "Connection: Keep-Alive" in its responses. In order to close the
  client socket connection explicitly after the response is sent and read
  successfully by the client, you simply have to set this option to False when
  you create a wsgi server.

Configuring the Health Check
----------------------------

This setting allows an operator to configure the endpoint URL that will
provide information to load balancer if given API endpoint at the node should
be available or not. Glance API server can be configured to expose a health
check URL.

To enable the health check middleware, it must occur in the beginning of the
application pipeline.

The health check middleware should be placed in your
``glance-api-paste.ini`` in a section titled ``[filter:healthcheck]``.
It should look like this::

  [filter:healthcheck]
  paste.filter_factory = oslo_middleware:Healthcheck.factory
  backends = disable_by_file
  disable_by_file_path = /etc/glance/healthcheck_disable

A ready-made application pipeline including this filter is defined e.g. in
the ``glance-api-paste.ini`` file, looking like so::

  [pipeline:glance-api]
  pipeline = healthcheck versionnegotiation osprofiler unauthenticated-context rootapp

For more information see
`oslo.middleware <https://docs.openstack.org/oslo.middleware/latest/reference/api.html#oslo_middleware.Healthcheck>`_.

Configuring supported disk formats
----------------------------------

Each image in Glance has an associated disk format property.
When creating an image the user specifies a disk format. They must
select a format from the set that the Glance service supports. This
supported set can be seen by querying the ``/v2/schemas/images`` resource.
An operator can add or remove disk formats to the supported set.  This is
done by setting the ``disk_formats`` parameter which is found in the
``[image_format]`` section of ``glance-api.conf``.

``disk_formats=<Comma separated list of disk formats>``
  Optional. Default: ``ami,ari,aki,vhd,vhdx,vmdk,raw,qcow2,vdi,iso,ploop``
