First steps in servlerless

I’m starting a new job next month where I’ll be using AWS Lambda. In preparation, I’ve been cramming on the topic. The main resource I’ve used is O’Reilly’s Programming AWS Lambda, and I’m enjoying learning from an actual physical book with an animal on the cover.

Here’s a quick summary of some of the other sources I’ve been looking at:

  • Mike Robert’s Serverless Architectures post is massive, and full of really useful discussion. This includes: a comparison between serverless and stored procedures (vendor locking, difficulty testing and versioning); the value of reduced time to market; environmental benefits of serverless; and the challenges of integration testing.
  • Gunnar Morling produced a good infoQ talk, Serverless Search for my blog, which discusses AWS Lambda used for a Lucene-based blog search. Morling uses Quarkus to avoid lock-in, and also suggests this gets around the cold-start problem. He also suggested Funqy as an vendor independent abstraction for serverless code. Morling points out that serverless has a smaller attack service, but looked in detail at dealing with a ‘denial of wallet’ attack.
  • Bruce Schneier discussed The Misaligned Incentives for Cloud Security, warning that it has a few large providers making technical decisions for millions of users; and that security problems such as data breaches affect their customers more than it affects them.
  • Guy Podjarny talks about the security issues in greater detail in Serverless security: What’s left to protect. He points out that one still needs to consider dependency vulnerabilities. While security permissions in serverless can be very granular, there is also a risk of this sprawling. Podjarny makes a number of suggestions including having critical and non-critical functionality in different accounts or regions.
  • Serverless and Chatbots: A Match Made in the Cloud by Gillian Armstrong was focussed on chatbots, but had a good overview of a lambda-based platform in production. Armstrong also noted that while lambdas scale every quickly, other parts of an infrastructure such as datastores might not.
  • A 2020 article Why the Serverless Revolution Has Stalled takes a more cynical approach, looking at four potential issues: limited programming languages; vendor lock; performance; inability to replace monolithic applications. Some of these issues have been solved by some teams, but all these points are worth considering.
  • Cloud study by the writer Robin Sloan discusses his use of cloud functions to provide simple support for running his newsletter. His solution to the cold start problem is, he admits, not best practise, but works for him: “Instead of deploying each of my functions as Actually Different cloud functions, I’ve rolled them up into one “mega function”—really almost a tiny app.” This solves a lot of issues for this small piece of functionality, not least that it fails fast: “if something isn’t working, nothing is working
  • Another post on cold starts suggested reducing the artefact size and had a good discussion of using pings to keep services live.
  • Operational Best Practices #serverless talked about how serverless limits the amount of code an enterprise needed, and that BaaS, FaaS and BaaS can all help speed up dev, particularly early in the process “You get to rent engineers from Google, AWS, Pagerduty, Pingdom, Heroku, etc for much cheaper than if you hired them in-house — if you could even get them, which you probably can’t because talent is scarce.”
  • That piece also contains a stern warning: “there is no such thing as having the luxury of not having to understand how your storage systems work. Queries will get slow, and you’ll need to be able to figure out why and fix them. You’ll hit scaling cliffs where suddenly a perfectly-usable app just starts timing everything out because of that extra second of latency coming from … The more you understand about your storage system (and the more you stay in the lane of how it was intended to be used), the happier you’ll be.

Using serverless for hobby projects does look attractive. But, having tried to get S3 and IAM working on AWS, I’d be reluctant to suggest that to anyone – particularly given the financial perils of AWS.

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