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Configuring Glance
==================

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

Most configuration is done via configuration files, with the Glance API
server and Glance Registry server using separate configuration files.

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

* ``$CWD``
* ``~/.glance``
* ``~/``
* ``/etc/glance``
* ``/etc``

The Glance API server configuration file should be named ``glance-api.conf``.
Similarly, the Glance Registry server configuration file should be named
``glance-registry.conf``. 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 to this documentation page, you can check the
``etc/glance-api.conf`` and ``etc/glance-registry.conf`` sample configuration
files distributed with Glance for example configuration files for each server
application with detailed comments on what each options does.

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: ``None``

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:

* ``$CWD``
* ``~/.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,
otherwise ``glance-registry.conf``.

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.

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`` config file in the section ``[DEFAULT]``.

* ``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``, or ``s3``).

* ``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.

* ``swift_store_auth_address=URL``

Required when using the Swift storage backend.

Can only be specified in configuration files.

`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 <http://swift.openstack.org/overview_auth.html>`_ 
documentation and the
`overview of Swift authentication <http://docs.openstack.org/openstack-object-storage/admin/content/ch02s02.html>`_.

* ``swift_store_user=USER``

Required when using the Swift storage backend.

Can only be specified in configuration files.

`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.

`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.

Configuring the Glance Registry
-------------------------------

Glance ships with a default, reference implementation registry server. There
are a number of configuration options in Glance that control how this registry
server operates. These configuration options are specified in the
``glance-registry.conf`` config file in the section ``[DEFAULT]``.

* ``sql_connection=CONNECTION_STRING`` (``--sql-connection`` when specified
  on command line)

Optional. Default: ``None``

Can be specified in configuration files. Can also be specified on the
command-line for the ``glance-manage`` program.

Sets the SQLAlchemy connection string to use when connecting to the registry
database. Please see the documentation for
`SQLAlchemy connection strings <http://www.sqlalchemy.org/docs/05/reference/sqlalchemy/connections.html>`_
online.

* ``sql_timeout=SECONDS``
  on command line)

Optional. Default: ``3600``

Can only be specified in configuration files.

Sets the number of seconds after which SQLAlchemy should reconnect to the
datastore if no activity has been made on the connection.
