Elastic Algorithm Service (EAS) offers both public and exclusive resource groups. To reduce costs when deploying a service to EAS using a public resource group, you can opt for preemptible instances. This topic guides you through the process of specifying preemptible instances for an EAS service.
Introduction to preemptible instances
A preemptible instance is a cost-effective computing resource that operates on a preemptive mode by allowing you to set a price ceiling. EAS enables the selection of preemptible instances during service deployment. For more information, see preemptible instance.
Advantages
Cost savings: Preemptible instances are priced lower than standard pay-as-you-go instances, with real-time price fluctuations based on market supply and demand, often resulting in significant discounts.
Price tiers: Preemptible instances come in two types: with and without a protection period. The pricing, from lowest to highest, is as follows: price without protection period < price with protection period < standard instance price.
Purchase and use
Purchase configuration: You can indicate the use of preemptible instances in the configuration file and set a bid ceiling. The system will automatically bid for resources based on this configuration when deploying an EAS service.
Conditions for successful resource acquisition: A successful bid requires an adequate supply of preemptible instances and a bid that meets or exceeds the current market price.
Resource release and reallocation: Preemptible instances may be revoked due to inventory or market price changes. EAS will reallocate the highest priority active resources as per the configuration file to maintain service continuity.
Instance usage order during deployment: You can specify multiple instance types, such as preemptible and standard instances, when creating or updating a service. The system will utilize these instances in the order outlined in the configuration. If bidding fails or inventory is insufficient for a particular type, the system will automatically switch to the next available type in the sequence. For more information, see multiple instance types.
Usage rules
Instances with protection period:
By default, a minimum 1-hour protection period is provided to ensure resource availability.
After the protection period, continued usage is possible if inventory is available and the bid is at or above the market price.
Instances without protection period:
There is no protection period. Continued usage is possible if inventory is available and the bid is at or above the market price.
Release conditions:
With protection period: After the protection period, the instance may be released if inventory is insufficient or the bid falls below the market price.
Without protection period: The instance may be released if inventory is insufficient or the bid falls below the market price.
Billing model
Preemptible instances are billed on a pay-as-you-go basis, with charges based on the real-time market price.
Prerequisites
To use preemptible instances via a local client, you must download and authenticate the EASCMD client tool. For detailed instructions, see download and authenticate the client.
Use preemptible instances when creating a service
Modify service configuration to use preemptible instances
References
For more information about advanced configurations for service deployment, see Special Deployment Scenarios and Advanced Configuration.
For more information about public resource groups, see Overview of EAS Resource Groups.