3.3.10.6. Configuration Reference

Table 3.21. Description of configuration options for scheduling

Configuration option=Default value Description
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=10.0 (FloatOpt) Multiplier used for weighing ram. Negative numbers mean to stack vs spread.
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_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_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_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_topic=scheduler (StrOpt) the topic scheduler nodes listen on
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.
scheduler_weight_classes=nova.scheduler.weights.all_weighers (ListOpt) Which weight class names to use for weighing hosts