Requirements

• localrc has served well in its capacity of the sole container of local configuration. Being a single file makes it easy to track and share known working DevStack configurations. Any new configuration scheme must preserve this property.
• In order to be able to set attributes in arbitrary configuration files and sections, those bits of information must be encoded in the new format.
• There must be a mechanism to selectively merge the configuration values into their destination files rather than do them all at once.
• Reduce the number of configuration variables in general that are simply passed-through to project config files. They are being set in localrc anyway, moving that to another section of local.conf is not a difficult transition.
• Backward-compatibility is a must; existing localrc files must continue to work as expected. In order to utilize any of the new capability, localrc must be converted to the local.conf local section.

Solution

Support has been added for a new master local configuration file local.conf that, like localrc, resides in the root DevStack directory and is not included in the DevStack repo. local.conf contains all local configuration for DevStack, including a direct replacement for localrc. It is an extended-INI format that introduces a new meta-section header containing the additional information required: a phase name and destination configuration filename. It has the form:

[[ <phase> | <filename> ]]

where <phase> is one of a set of phase names defined below by stack.sh and <filename> is the configuration filename. The filename is eval'ed in the stack.sh context so all environment variables are available and may be used (see example below). Using the configuration variables from the project library scripts (e.g. lib/nova) in the header is strongly suggested (see example of NOVA_CONF below).

Configuration files specifying a path that does not exist are skipped. This allows services to be disabled and still have configuration files present in local.conf. For example, if Nova is not enabled and /etc/nova does not exist, attempts to set a value in /etc/nova/nova.conf will be skipped. If /etc/nova does exist, nova.conf will be created if it does not exist. This should be mostly harmless.

The defined phases are:

• local - extracts the localrc section from local.conf before stackrc is sourced
• post-config - runs after the layer 2 services are configured and before they are started
• extra - runs after services are started and before any files in extra.d are executed

local.conf is processed strictly in sequence; meta-sections may be specified more than once but if any settings are duplicated the last to appear in the file will survive.

The post-config phase is where most of the configuration-setting activity takes place. In the following example, syslog and the Compute v3 API are enabled. Note the use of $NOVA_CONF to properly locate nova.conf.

[[post-config|$NOVA_CONF]] [DEFAULT] use_syslog = True

[osapi_v3] enabled = False

A special meta-section [[local|localrc]] is used to replace the function of the old localrc file. This section is written to .localrc.auto if locarc does not exist; if it does exist localrc is not overwritten to preserve compatability:

[[local|localrc]]
FIXED_RANGE=10.254.1.0/24
ADMIN_PASSWORD=speciale
LOGFILE=$DEST/logs/stack.sh.log

Implementation

Four new functions were added to parse and merge local.conf into existing INI-style config files. The base functions file is getting way too large so these functions are in lib/config which will contain functions related to config file manipulation. The existing iniXXX() functions may also eventually move here. There shall be no side-effects or global dependencies from any of the functions in lib/config.

• get_meta_section() - Returns an INI fragment for a specific group/filename combination
• get_meta_section_files() - Returns a list of the config filenames present in local.conf for a specific group
• merge_config_file() - Performs the actual merge of the INI fragment from local.conf
• merge_config_group() - Loops over the INI fragments present for the specified group and merges them

The merge is performed after the install_XXX() and configure_XXX() functions for all layer 1 and 2 projects are complete and before any services are started.

The Deprecated Variables

The list of existing variables that will be deprecated in favor of using local.conf currently includes EXTRA_OPTS and a handful of Q_XXX_XXX_OPTS variables in Neutron. These are listed at the end of stack.sh runs as deprecated and will be removed sometime in the Icehouse development cycle after DevStack's stable/havana branch is in place and Grenade's Grizzly->Havana upgrade is operational.

Examples

• Convert EXTRA_OPTS from:

  EXTRA_OPTS=api_rate_limit=False
  
  to
  
  [[post-config|$NOVA_CONF]]
  [DEFAULT]
  api_rate_limit = False
  

• Convert multiple EXTRA_OPTS values from:

  EXTRA_OPTS=(api_rate_limit=False default_log_levels=sqlalchemy=WARN)
  
  to
  
  [[post-config|$NOVA_CONF]]
  [DEFAULT]
  api_rate_limit = False
  default_log_levels = sqlalchemy=WARN
  

• Eliminate a Cinder pass-through (CINDER_PERIODIC_INTERVAL):

  [[post-config|$CINDER_CONF]]
  [DEFAULT]
  periodic_interval = 60
  

• Change a setting that has no variable:

  [[post-config|$CINDER_CONF]]
  [DEFAULT]
  iscsi_helper = new-tgtadm
  

• Basic complete config:

  [[post-config|$NOVA_CONF]]
  [DEFAULT]
  api_rate_limit = False
  
  [vmware]
  host_ip = $HOST_IP
  host_username = root
  host_password = deepdarkunknownsecret
  
  
  [[post-config|$CINDER_CONF]]
  [DEFAULT]
  periodic_interval = 60
  
  vmware_host_ip = $HOST_IP
  vmware_host_username = root
  vmware_host_password = deepdarkunknownsecret
  
  
  [[local|localrc]]
  FIXED_RANGE=10.254.1.0/24
  NETWORK_GATEWAY=10.254.1.1
  LOGDAYS=1
  LOGFILE=$DEST/logs/stack.sh.log
  SCREEN_LOGDIR=$DEST/logs/screen
  ADMIN_PASSWORD=quiet
  DATABASE_PASSWORD=$ADMIN_PASSWORD
  RABBIT_PASSWORD=$ADMIN_PASSWORD