[20170803165841] Spot Instances (Experimental)

Spot Instances

This release adds the ability to use EC2 spot instances in your ECS cluster.

This feature is experimental, and you may see intermittent app downtime when using it.

It introduces 2 new Rack parameters:

  • SpotInstanceBid
  • OnDemandMinCount

If you set a $USD value for SpotInstanceBid, Convox will attempt to boot spot instances to replace your On Demand instances.

If the spot instances are successfully started, Convox will slowly shut down On Demand instances until your total Spot + On Demand instance count equals the InstanceCount parameter.

If spot instances are terminated by AWS (outbid or lack of availability), On Demand instances will be booted back up to bring the total back to InstanceCount.

The OnDemandMinCount parameter can be set to configure a minimum number of on-demand instances that won’t be replaced with spots. Its default value is 3.

To stop using spot instances, simply unset SpotInstanceBid:

convox rack params set SpotInstanceBid=

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