Configuration for the size bounds of an instance group, including its proportional size to other groups. .. attribute:: min_instances
Optional. Minimum number of instances for this group. Primary workers - Bounds: [2, max_instances]. Default: 2. Secondary workers - Bounds: [0, max_instances]. Default: 0.
Optional. Weight for the instance group, which is used to
determine the fraction of total workers in the cluster from
this instance group. For example, if primary workers have
weight 2, and secondary workers have weight 1, the cluster
will have approximately 2 primary workers for each secondary
worker. The cluster may not reach the specified balance if
constrained by min/max bounds or other autoscaling settings.
For example, if max_instances for secondary workers is 0,
then only primary workers will be added. The cluster can also
be out of balance when created. If weight is not set on any
instance group, the cluster will default to equal weight for
all groups: the cluster will attempt to maintain an equal
number of workers in each group within the configured size
bounds for each group. If weight is set for one group only,
the cluster will default to zero weight on the unset group.
For example if weight is set only on primary workers, the
cluster will use primary workers only and no secondary
workers.