SpotFleetMinOnDemandCount
Spot Fleet's minimum on-demand instance count. This ensures a baseline of guaranteed, non-interruptible capacity alongside your Spot instances. The instance type for on-demand instances is taken from the InstanceType parameter. This parameter can be used only when Spot Fleet is enabled by setting SpotFleetMaxPrice.
| Default value (if HighAvailability disabled) | 1 |
| Default value (if HighAvailability enabled) | 2 |
The CloudFormation default is 1. When HighAvailability is enabled, the Rack automatically adjusts this to 2 to ensure redundancy.
Use Cases
- Increasing the on-demand count for production workloads to guarantee a minimum level of availability even if all Spot instances are reclaimed
- Setting to
1for development environments where brief interruptions are acceptable - Setting higher than the default to ensure critical services always have dedicated capacity
Additional Information
On-demand instances provide guaranteed capacity that cannot be interrupted by AWS, unlike Spot instances which can be reclaimed with a two-minute warning. By maintaining a minimum number of on-demand instances, you ensure that your Rack always has baseline capacity to run essential services.
This parameter only takes effect when Spot Fleet is enabled via SpotFleetMaxPrice.
$ convox rack params set SpotFleetMinOnDemandCount=3
See Also
