Description of configuration options for scheduling

Configuration option = Default value	Description
[DEFAULT]
aggregate_image_properties_isolation_namespace = None	(StrOpt) Force the filter to consider only keys matching the given namespace.
aggregate_image_properties_isolation_separator = .	(StrOpt) The separator used between the namespace and keys
cpu_allocation_ratio = 16.0	(FloatOpt) Virtual CPU to physical CPU allocation ratio which affects all CPU filters. This configuration specifies a global ratio for CoreFilter. For AggregateCoreFilter, it will fall back to this configuration value if no per-aggregate setting found.
disk_allocation_ratio = 1.0	(FloatOpt) virtual disk to physical disk allocation ratio
isolated_hosts =	(ListOpt) Host reserved for specific images
isolated_images =	(ListOpt) Images to run on isolated host
max_instances_per_host = 50	(IntOpt) Ignore hosts that have too many instances
max_io_ops_per_host = 8	(IntOpt) Ignore hosts that have too many builds/resizes/snaps/migrations
ram_allocation_ratio = 1.5	(FloatOpt) Virtual ram to physical ram allocation ratio which affects all ram filters. This configuration specifies a global ratio for RamFilter. For AggregateRamFilter, it will fall back to this configuration value if no per-aggregate setting found.
ram_weight_multiplier = 1.0	(FloatOpt) Multiplier used for weighing ram. Negative numbers mean to stack vs spread.
reserved_host_disk_mb = 0	(IntOpt) Amount of disk in MB to reserve for the host
reserved_host_memory_mb = 512	(IntOpt) Amount of memory in MB to reserve for the host
restrict_isolated_hosts_to_isolated_images = True	(BoolOpt) Whether to force isolated hosts to run only isolated images
scheduler_available_filters = ['nova.scheduler.filters.all_filters']	(MultiStrOpt) Filter classes available to the scheduler which may be specified more than once. An entry of "nova.scheduler.filters.standard_filters" maps to all filters included with nova.
scheduler_default_filters = RetryFilter, AvailabilityZoneFilter, RamFilter, ComputeFilter, ComputeCapabilitiesFilter, ImagePropertiesFilter	(ListOpt) Which filter class names to use for filtering hosts when not specified in the request.
scheduler_driver = nova.scheduler.filter_scheduler.FilterScheduler	(StrOpt) Default driver to use for the scheduler
scheduler_host_manager = nova.scheduler.host_manager.HostManager	(StrOpt) The scheduler host manager class to use
scheduler_host_subset_size = 1	(IntOpt) New instances will be scheduled on a host chosen randomly from a subset of the N best hosts. This property defines the subset size that a host is chosen from. A value of 1 chooses the first host returned by the weighing functions. This value must be at least 1. Any value less than 1 will be ignored, and 1 will be used instead
scheduler_json_config_location =	(StrOpt) Absolute path to scheduler configuration JSON file.
scheduler_manager = nova.scheduler.manager.SchedulerManager	(StrOpt) full class name for the Manager for scheduler
scheduler_max_attempts = 3	(IntOpt) Maximum number of attempts to schedule an instance
scheduler_topic = scheduler	(StrOpt) the topic scheduler nodes listen on
scheduler_weight_classes = nova.scheduler.weights.all_weighers	(ListOpt) Which weight class names to use for weighing hosts
[cells]
ram_weight_multiplier = 10.0	(FloatOpt) Multiplier used for weighing ram. Negative numbers mean to stack vs spread.
scheduler_filter_classes = nova.cells.filters.all_filters	(ListOpt) Filter classes the cells scheduler should use. An entry of "nova.cells.filters.all_filters"maps to all cells filters included with nova.
scheduler_retries = 10	(IntOpt) How many retries when no cells are available.
scheduler_retry_delay = 2	(IntOpt) How often to retry in seconds when no cells are available.
scheduler_weight_classes = nova.cells.weights.all_weighers	(ListOpt) Weigher classes the cells scheduler should use. An entry of "nova.cells.weights.all_weighers"maps to all cell weighers included with nova.
[metrics]
weight_multiplier = 1.0	(FloatOpt) Multiplier used for weighing metrics.
weight_setting =	(ListOpt) How the metrics are going to be weighed. This should be in the form of "<name1>=<ratio1>, <name2>=<ratio2>, ...", where <nameX> is one of the metric to be weighed, and <ratioX> is the corresponding ratio. So for "name1=1.0, name2=-1.0" The final weight would be name1.value * 1.0 + name2.value * -1.0.