Provisionned Competition on AWS Lambda: a really useful tool?

AWS Lambda: generate web functions simply

AWS is not changing its good habits and continues to announce new services to power its Cloud offer. Recently, the American giant announced the launch of a new service compatible with AWS Lambda: "Provisionned Concurrency". As you probably know, Lambda is a reference product in the AWS offer allowing the execution of functions without worrying about the deployment of a dedicated architecture. What will the simultaneous booking be used for? Is it a relevant tool adapted to your needs, or is it an additional invoicing line that you will not be able to control at the end of the month? We explain everything to you.

AWS identifies a need for reactivity

Lambda is a product known for its simplicity and flexibility that it brings to development teams. Execute a function or lines of code without regard to the technical architecture that runs behind is a luxury that many AWS users can nowadays enjoy to pay.

Behind an apparent simplicity, a false note can sometimes tarnish AWS Lambda's balance sheet: the speed of execution. The reactivity of web applications is a central issue for many teams and the use of Lambda sometimes confronts its users with this reality. Concretely: the invocation of a function on Lambda leads to the activation of an execution environment to proceed with the invoked request.

This is where Lambda can show its limits. After a certain period of inactivity, when you want to invoke several functions simultaneously or when you update a function, a new environment is created. Creating this new environment can lead to some latency, depending on the size of your deployment or the quality of your code.  

Classic reaction of a user waiting for a web page to load....

How does Provisionned Competition work?

This latency is comparable to the cold start of your old diesel. It will usually take a few minutes for your engine to is ready to take the rpm. It is the same for the execution environment on AWS Lambda: the creation of a new environment necessarily induces a launch time that will impact the reactivity of your function.

To counter this phenomenon, AWS has therefore created the "Provisionned Concurrency". In concrete terms, Amazon gives you now the opportunity to book execution environments already ready for to be used. Imagine a restaurant owner facing an early booking peak his restaurant is packed and must be able to accommodate all the guests. world without increasing the waiting time of its customers. The best one how to do it? Have about ten hot ovens ready to use to be the as efficient as possible.

This metaphor is not very ecological, we grant you that. But the principle is essentially the same: reserved simultaneity is similar to a reserve of ready-made equipment, without any induced latency.

The reservation area on the AWS Lambda interface.

Provisioned Competition: a FinOps friendly tool?

Not surprisingly: we are obviously not talking about a free product. If you are an AWS user, you know this better than we do: Amazon does not usually forget to bill for a new service. The question is therefore: is this service interesting from a cloud cost optimization perspective?

As is often the case, it is all a question of context. In terms of invoicing, as with all AWS products, you only pay for the quantity you want to reserve. However, pricing is rather vague: $0.015 per GB/h for Provisioned Competition and $0.035 per GB/h depending on the duration. It is therefore difficult to obtain real visibility on your future invoice. Eternal refrain.

Our advice before you start booking ready-to-use runtime environment: if your product has no need for responsiveness and speed of execution, there is no need to to think. Although this service seems practical and rather affordable, there is no need to pollute an already fuzzy invoice with unnecessary data.

On the other hand, in the case of a highly dependent business reaction times of its services, such as an e-commerce site for example, the profitability of such a service can really make a difference. Latency, too low, it can have a significant impact on the transformation rate of an e-merchant. AWS offers you here the possibility to better understand your consumption peaks to optimize your conversion rate.

Moral of the story: think of "Provisionned Competition" only if there is a real direct business need.

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