Did
this post load fast? 🚀 This is in no small part because the content
was delivered to your browser using Cloudflare's Workers. Workers
provides a high performance global network with a 0ms cold-start time.
Serverless today
Cloud
providers can allocate machine resources on demand, scaling
automatically to the requirements of your business. Two fundamental
technologies make this possible today: virtualization, and
containerization.
Virtualization is the process of
running a virtual instance of a computer system in a layer abstracted
from the actual hardware. Most commonly, it refers to running >
multiple operating systems on a computer system simultaneously.
opensource.com - https://opensource.com/resources/virtualization
Containerization
is the packaging of software code with just the operating system
libraries and dependencies required to run the code to create a single
lightweight executable.
IBM - https://www.ibm.com/cloud/learn/containerization
Whether
it’s Amazon’s ECS or Lambda, Google’s Cloud Run or Cloud Functions, or
any of the other modern offerings – services are built on these two
fundamental concepts.
Code deployed as containers to these cloud
services becomes a small independent workload that can be passed around
and run on different hardware. For all intents and purposes this works
really well, but providers make a trade-off between keeping your
workload ‘hot’ (ready to accept requests) and the cost of occupying
infrastructure.
Typically you can take over the trade-off with
controls given to you from the provider, but you will need to decide:
low cost with longer initial start times, or hot and ready with a higher
cost. Businesses generally accept the cost associated with always
having a workload running to eliminate the 'cold start', especially when
the workload has to load a user experience like a web application.
Lambda cold starts
My
team at ASICS Apps struggled with this very problem last year when
experimenting with Next.js and AWS Lambda. We were attracted to the
atomic nature, and billing per execution time. Using the custom server
feature of Next.js, our demo projects looked very promising, and didn’t
require a large time investment from our infrastructure team.
Unfortunately we couldn't find a reliable solution to bring down cold
requests consistently under three seconds, unacceptable for business
requirements and set standards. This is especially the case when a
lambda is delivering a visual interactive experience. I'm unsure I would
recommend Lambda to serve a modern application experience like with
Next.js, but can definitely see value for background tasks, or service
to service cron workloads.
In the end, we chose AWS Elastic
Container Service configured to guarantee a hot workload (never shutting
off). Meaning we have accepted the cost of running a container every
minute of every day to guarantee an instance response to user requests.
Can we do better?
Cloudflare Workers
Faced
with recent problems with Lambda at work, and not wanting to pay
monthly to run this simple blog, Cloudflare Workers was the perfect
solution.
You can think of Workers as a giant web browser running
in the cloud. When a request is handled by Workers it’s akin to opening
another tab. This comparison works well as a mental model because the
Workers runtime uses the V8 engine — the same engine used by Chromium
and Node.js. Instead of needing to package code in a container, you only
need to adapt the worker syntax for application entry points. Unlike
your web browser, the code is executed inside the server environment
allowing your application access to privileged secrets, rendering
content server-side, or completing costly calculations.
This blog
is built with the latest version of Nuxt, an opinionated hybrid Vue
framework that delivers high quality web experiences. With Cloudflare
Workers I no longer worry about choosing between cold starts or paying a
premium in addition to containerizing my application. This blog is now
instantly available anywhere in the world, with very low latency and no
cold starts.
Comparison: AWS Lambda vs ECS vs Cloudflare Workers
| Feature | AWS Lambda | Cloudflare Workers |
|---|
| Cold Start | Yes (can be several sec) | No (0ms, always ready) |
| Pricing Model | Per execution time | Per request, generous free |
| Deployment | Package as zip/container | JavaScript/Worker script |
| Scalability | Automatic, event-driven | Automatic, edge network |
| Latency | Variable, cold start risk | Very low, global edge |
| Limitations | Cold starts, memory/time | Runtime limits, JS only |
This
table highlights the main differences between AWS Lambda and Cloudflare
Workers. Cloudflare Workers stands out for its instant availability and
global reach, making it ideal for web applications and APIs that
require low latency and no cold starts.
Conclusion
In
summary, Cloudflare Workers offer a compelling solution for developers
seeking instant, global availability and minimal latency for their web
applications. By eliminating cold starts and simplifying deployment,
Workers empower teams to deliver fast, reliable experiences to users
worldwide. If you’re building modern web apps or APIs, it’s worth
considering Cloudflare Workers for your next project.
from https://jamesvan.ca/post/cf-workers-coldstarts
