openstack-manuals/doc/config-ref-rst/source/config-format.rst
John Davidge c400d9b2f0 Un-comment config options for consistency
Two of the config options in this section are commented out.

Un-comment them to match with the rest of the document,
and to improve readability.

Change-Id: I6b52e700463906e2705465d4c2cc01ca45aad49e
Closes-Bug: #1514930
2015-11-13 14:53:44 +00:00

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=========================
Configuration file format
=========================
OpenStack uses the :term:`INI` file format for configuration files.
An INI file is a simple text file that specifies options as
``key=value`` pairs, grouped into sections.
The ``DEFAULT`` section contains most of the configuration options.
Lines starting with a hash sign (``#``) are comment lines.
For example:
.. code-block:: ini
[DEFAULT]
# Print debugging output (set logging level to DEBUG instead
# of default WARNING level). (boolean value)
debug = true
# Print more verbose output (set logging level to INFO instead
# of default WARNING level). (boolean value)
verbose = true
[database]
# The SQLAlchemy connection string used to connect to the
# database (string value)
connection = mysql+pymysql://keystone:KEYSTONE_DBPASS@controller/keystone
Options can have different types for values.
The comments in the sample config files always mention these.
The following types are used by OpenStack:
boolean value
Enables or disables an option. The allowed values are ``true`` and ``false``.
.. code-block:: ini
# Enable the experimental use of database reconnect on
# connection lost (boolean value)
use_db_reconnect = false
floating point value
A floating point number like ``0.25`` or ``1000``.
.. code-block:: ini
# Sleep time in seconds for polling an ongoing async task
# (floating point value)
task_poll_interval = 0.5
integer value
An integer number is a number without fractional components,
like ``0`` or ``42``.
.. code-block:: ini
# The port which the OpenStack Compute service listens on.
# (integer value)
compute_port = 8774
list value
Represents values of other types, separated by commas.
As an example, the following sets ``allowed_rpc_exception_modules``
to a list containing the four elements ``oslo.messaging.exceptions``,
``nova.exception``, ``cinder.exception``, and ``exceptions``:
.. code-block:: ini
# Modules of exceptions that are permitted to be recreated
# upon receiving exception data from an rpc call. (list value)
allowed_rpc_exception_modules = oslo.messaging.exceptions,nova.exception
multi valued
A multi-valued option is a string value and can be given
more than once, all values will be used.
.. code-block:: ini
# Driver or drivers to handle sending notifications. (multi valued)
notification_driver = nova.openstack.common.notifier.rpc_notifier
notification_driver = ceilometer.compute.nova_notifier
string value
Strings can be optionally enclosed with single or double quotes.
.. code-block:: ini
# Enables or disables publication of error events. (boolean value)
publish_errors = false
# The format for an instance that is passed with the log message.
# (string value)
instance_format = "[instance: %(uuid)s] "
Sections
~~~~~~~~
Configuration options are grouped by section.
Most configuration files support at least the following sections:
[DEFAULT]
Contains most configuration options.
If the documentation for a configuration option does not
specify its section, assume that it appears in this section.
[database]
Configuration options for the database that stores
the state of the OpenStack service.
Substitution
~~~~~~~~~~~~
The configuration file supports variable substitution.
After you set a configuration option, it can be referenced
in later configuration values when you precede it with
a ``$``, like ``$OPTION``.
The following example uses the values of ``rabbit_host`` and
``rabbit_port`` to define the value of the ``rabbit_hosts``
option, in this case as ``controller:5672``.
.. code-block:: ini
# The RabbitMQ broker address where a single node is used.
# (string value)
rabbit_host = controller
# The RabbitMQ broker port where a single node is used.
# (integer value)
rabbit_port = 5672
# RabbitMQ HA cluster host:port pairs. (list value)
rabbit_hosts = $rabbit_host:$rabbit_port
To avoid substitution, use ``$$``, it is replaced by a single ``$``.
For example, if your LDAP DNS password is ``$xkj432``, specify it, as follows:
.. code-block:: ini
ldap_dns_password = $$xkj432
The code uses the Python ``string.Template.safe_substitute()``
method to implement variable substitution.
For more details on how variable substitution is resolved, see
http://docs.python.org/2/library/string.html#template-strings
and `PEP 292 <http://www.python.org/dev/peps/pep-0292/>`_.
Whitespace
~~~~~~~~~~
To include whitespace in a configuration value, use a quoted string.
For example:
.. code-block:: ini
ldap_dns_passsword='a password with spaces'
Define an alternate location for a config file
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Most services and the ``*-manage`` command-line clients load
the configuration file.
To define an alternate location for the configuration file,
pass the ``--config-file CONFIG_FILE`` parameter
when you start a service or call a ``*-manage`` command.