openstack-manuals/doc/config-ref-rst/source/config-format.rst

Configuration file format

OpenStack uses the 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:

[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.

# 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.

# 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.

# 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:

# 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.

# 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.

# 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.

# 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:

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.

Whitespace

To include whitespace in a configuration value, use a quoted string. For example:

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.