OpenStack configuration overview

OpenStack is a collection of open source project components that enable setting up cloud services. Each component uses similar configuration techniques and a common framework for INI file options.

This guide pulls together multiple references and configuration options for the following OpenStack components:

  • OpenStack Block Storage

  • OpenStack Compute

  • OpenStack Dashboard

  • Database Service

  • OpenStack Identity

  • OpenStack Image Service

  • OpenStack Networking

  • OpenStack Object Storage

  • Telemetry

  • Orchestration

1. 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://keystone:KEYSTONE_DBPASS@controller/keystone

Options can have different type 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,cinder.exception,exceptions
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. 

​# onready allows you to send a notification when the process
​# is ready to serve. For example, to have it notify using
​# systemd, one could set shell command: "onready = systemd-
​# notify --ready" or a module with notify() method: "onready =
​# keystone.common.systemd". (string value)
​onready = systemd-notify --ready
​
​# If an instance is passed with the log message, format it
​# like this (string value)
​instance_format = "[instance: %(uuid)s] "

1.1. Sections

Configuration options are grouped by section. Most configuration file supports 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.

1.2. 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.

1.3. Whitespace

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

​ldap_dns_passsword='a password with spaces'

1.4. Define an alternate location for a config file

Most services and the 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.