Cost-Limited Droplet Creation w/ auto-destroy

February 7, 2017 499 views
Miscellaneous

Is there a means to create a droplet with a cost limit?

Suppose I am building a service on top of Digital Ocean droplets, and I want to purchase some free trial time for users. Lets say I want to create droplets on their behalf to run a service in a sandboxed manner.

Is there a way to set a limit on a droplet's cost use. EG, I want to create a droplet but not have it spend more than 10 cents. If it reaches 10 cents, it auto-destroys.

I want to have a guarantee that a malicious user or mistake will not accidentally burn a bunch of cash.

2 Answers

You can use the API to monitor your droplets and destroy them if necessary.

  • Monitoring and destroying is a strategy that is 'active', and default-fail. If the monitor fails to act, I am on the hook.

    I am interested in a passive solution.

    If the limit could be set at creation-time of the droplet that would differentiate this product from other cloud services.

    I can kind of imagine that it might be difficult from an engineering perspective to actually place a guarantee on process killing -- as I think it is fundamentally an active process to monitor use, and operating systems and hardware do not truly support this feature at the bare-metal level. If I'm wrong about this I would love to hear about it.

    • There is no passive solution at this time and I'm guessing there is little need for it as well.

@williamsharkey

This isn't something that is possible by default -- you'd have to bake this in to your application.

When a Droplet is created using the API, you'll receive a JSON object as a response and within it, you can pull created_at, which is described as:

A time value given in ISO8601 combined date and time format that represents when the Droplet was created

To get the total time that a Droplet has been active, you'd simply get the different between the current time and the one provided by created_at. You'd then compare that against however long you allow them to use the service for free and if it meets or exceeds, issue a destroy command.

https://developers.digitalocean.com/documentation/v2/#create-a-new-droplet

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