The node_capacity_type
parameter specifies the type of capacity for the cluster nodes. It can be set to on_demand
, spot
, or mixed
.
on_demand
: Uses AWS on-demand instances for the cluster nodes.spot
: Uses AWS spot instances for the cluster nodes.mixed
: Creates one node group with on-demand instances and the other two with spot instances. Use mixed
with the min_on_demand_count and max_on_demand_count parameters to control the minimum and maximum number of on-demand nodes, ensuring acceptable service availability even if spot instances become unavailable.The default value for node_capacity_type
is on_demand
.
spot
or mixed
capacity types to reduce costs by leveraging lower-cost spot instances while maintaining a baseline of reliable on-demand instances.on_demand
capacity type for maximum reliability and performance, as on-demand instances are not subject to interruption like spot instances.To set the node_capacity_type
parameter, use the following command:
$ convox rack params set node_capacity_type=mixed -r rackName
Setting parameters... OK
This command sets the node capacity type to mixed
.
When using the mixed
capacity type, it is important to configure the min_on_demand_count and max_on_demand_count parameters to ensure that your cluster maintains the desired balance of cost and reliability.
Using spot instances can lead to potential volatility as these instances may be interrupted by AWS when capacity is needed elsewhere. This setup is recommended only for non-production environments that can tolerate such interruptions.
By setting the node_capacity_type
parameter appropriately, you can optimize the cost-efficiency and reliability of your Convox rack based on your specific needs and workload requirements.