Description of configuration options for common

Configuration option = Default value	Description
[DEFAULT]
deferred_auth_method = password	(StrOpt) Select deferred auth method, stored password or trusts.
environment_dir = /etc/heat/environment.d	(StrOpt) The directory to search for environment files.
event_purge_batch_size = 10	(IntOpt) Controls how many events will be pruned whenever a stack's events exceed max_events_per_stack. Set this lower to keep more events at the expense of more frequent purges.
instance_driver = heat.engine.nova	(StrOpt) Driver to use for controlling instances.
instance_user = ec2-user	(StrOpt) The default user for new instances. This option is deprecated and will be removed in the Juno release. If it's empty, Heat will use the default user set up with your cloud image (for OS::Nova::Server) or 'ec2-user' (for AWS::EC2::Instance).
keystone_backend = heat.common.heat_keystoneclient.KeystoneClientV3	(StrOpt) Fully qualified class name to use as a keystone backend.
periodic_interval = 60	(IntOpt) Seconds between running periodic tasks.
plugin_dirs = /usr/lib64/heat, /usr/lib/heat	(ListOpt) List of directories to search for plug-ins.
[revision]
heat_revision = unknown	(StrOpt) Heat build revision. If you would prefer to manage your build revision separately, you can move this section to a different file and add it as another config option.