[nlg]

Thanks for coming here to answer questions. Much appreciated!

Does each new Lambda cold start pull the entire image from the repo? Or if I derive from Lambda base images am I likely to get some of the layers already cached?

I'm trying to think about how the data transfer costs are going to each time the Lambda is instantiated. I didn't take this into account with Fargate and got burned when trying to trigger images on demand in a similar way.

This could replace my whole SQS / CloudWatch Events / Fargate setup using Lambda if I can figure out cold start costs ($ not time).

[munns]

There's a few things at play. Functions will still stay warm inbetween invocations and will keep local any data already in the worker. We also maintain a couple different levels of cache so as to not hit ECR often.

I know we've got a few blog posts coming out over the next couple weeks on this new feature, and each tells a few bits and pieces about the story.

Depending on volume you'll probably find that Lambda will be cheaper for that workload, especially with the new 1ms billing.

- Chris - Serverless@AWS

[stephanos2k]

FWIW, a little experimented I just ran showed me that with simple layers the cold start time of my little 3MB Go app was <100ms, using the Docker image `amazon/aws-lambda-go:1` instead took ~1500ms.

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REPORT RequestId: f905d5fe-a64e-48c8-b1f2-6535640a6f82 Duration: 7.55 ms Billed Duration: 1309 ms Memory Size: 256 MB Max Memory Used: 49 MB Init Duration: 1301.10 ms

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REPORT RequestId: 89afb20d-bc49-4d89-91f0-f1ef62ac99aa Duration: 12.20 ms Billed Duration: 13 ms Memory Size: 256 MB Max Memory Used: 35 MB Init Duration: 85.37 ms