You finally built that amazing start-up idea you had in mind for years and you did it using Node.js! That's Great! You just launched it on Hacker News and you are very happy and proud... but now more and more people are using it and you start to have a nasty fear that Node.js won't scale because you now... it's single-threaded! Is your project doomed now? Do you have to invest your time on rewriting it in something like C++ or maybe Rust or even Go? You'd rather invest your time on adding valuable features for your users rather than learning a new language and rewriting everything from scratch, but what if nothing works anymore? And... by the way, what the heck "single-threaded" really means?! Fear no more, dear fellow developer! In this talk, we will discuss the architecture of Node.js going through its strengths and its weaknesses. We will then talk about scalability and I will share some valuable tips and tricks to make your Node.js app scale! Spoiler alert: you probably won't need Go or Rust :)

1. Node.js
Scalability Tips
Luciano Mammino ( )@loige
2020-07-09
loige.link/node-scale
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2. 👋 Hello, I am Luciano!
Principal Software Engineer at FabFitFun
Blog:
Twitter:
GitHub:
loige.co
@loige
@lmammino
nodejsdp.link/3rd
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3. @loige
Get the slides!
loige.link/node-scale
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4. Node.js + Scalability? 🤔
@loige
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5. @loige
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6. @loige
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7. @loige
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8. @loige
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9. @loige
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10. @loige
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11. @loige
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12. @loige
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13. @loige
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14. 🤣
@loige
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15. "Scalability is the property of a system to
handle a growing amount of work by
adding resources to the system"
— Wikipedia
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16. "A service is said to be scalable if when
we increase the resources in a
system, it results in increased
performance in a manner
proportional to resources added"
— Werner Vogels
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17. 🛫
Tip 1.
Establish a baseline
@loige
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18. /?data=Hello%20Shift
https://repl.it/@lmammino/QRGen
@loige
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19. const { createServer } = require('http')
const { URL } = require('url')
const QRCode = require('qrcode')
createServer(function handler (req, res) {
const url = new URL(req.url, 'http://localhost:8080')
const data = url.searchParams.get('data')
if (!data) {
res.writeHead(400) // bad request
return res.end()
}
res.writeHead(200, { 'Content-Type': 'image/png' })
QRCode.toFileStream(res, data, { width: 300 })
})
.listen(8080)
@loige
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20. autocannon -c 200 --on-port / -- node server.js
wrk
node server.js&
wrk -t8 -c200 -d10s http://localhost:8080/
@loige
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21. autocannon -c 200 --on-port /?data=Hello%20Shift -- node server.js
Running 10s test @ http://localhost:8080/?data=Hello%20Shift
200 connections
┌─────────┬─────────┬─────────┬─────────┬─────────┬────────────┬─────────┬────────────┐
│ Stat │ 2.5% │ 50% │ 97.5% │ 99% │ Avg │ Stdev │ Max │
├─────────┼─────────┼─────────┼─────────┼─────────┼────────────┼─────────┼────────────┤
│ Latency │ 1899 ms │ 1951 ms │ 2053 ms │ 2054 ms │ 1964.92 ms │ 99.9 ms │ 3364.03 ms │
└─────────┴─────────┴─────────┴─────────┴─────────┴────────────┴─────────┴────────────┘
┌───────────┬─────┬──────┬─────────┬────────┬────────┬────────┬─────────┐
│ Stat │ 1% │ 2.5% │ 50% │ 97.5% │ Avg │ Stdev │ Min │
├───────────┼─────┼──────┼─────────┼────────┼────────┼────────┼─────────┤
│ Req/Sec │ 0 │ 0 │ 30 │ 199 │ 99.5 │ 94.27 │ 30 │
├───────────┼─────┼──────┼─────────┼────────┼────────┼────────┼─────────┤
│ Bytes/Sec │ 0 B │ 0 B │ 50.7 kB │ 336 kB │ 168 kB │ 159 kB │ 50.7 kB │
└───────────┴─────┴──────┴─────────┴────────┴────────┴────────┴─────────┘
Req/Bytes counts sampled once per second.
995 requests in 10.08s, 1.68 MB read
@loige
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22. autocannon -c 200 --on-port /?data=Hello%20Shift -- node server.js
Running 10s test @ http://localhost:8080/?data=Hello%20Shift
200 connections
┌─────────┬─────────┬─────────┬─────────┬─────────┬────────────┬─────────┬────────────┐
│ Stat │ 2.5% │ 50% │ 97.5% │ 99% │ Avg │ Stdev │ Max │
├─────────┼─────────┼─────────┼─────────┼─────────┼────────────┼─────────┼────────────┤
│ Latency │ 1899 ms │ 1951 ms │ 2053 ms │ 2054 ms │ 1964.92 ms │ 99.9 ms │ 3364.03 ms │
└─────────┴─────────┴─────────┴─────────┴─────────┴────────────┴─────────┴────────────┘
┌───────────┬─────┬──────┬─────────┬────────┬────────┬────────┬─────────┐
│ Stat │ 1% │ 2.5% │ 50% │ 97.5% │ Avg │ Stdev │ Min │
├───────────┼─────┼──────┼─────────┼────────┼────────┼────────┼─────────┤
│ Req/Sec │ 0 │ 0 │ 30 │ 199 │ 99.5 │ 94.27 │ 30 │
├───────────┼─────┼──────┼─────────┼────────┼────────┼────────┼─────────┤
│ Bytes/Sec │ 0 B │ 0 B │ 50.7 kB │ 336 kB │ 168 kB │ 159 kB │ 50.7 kB │
└───────────┴─────┴──────┴─────────┴────────┴────────┴────────┴─────────┘
Req/Bytes counts sampled once per second.
995 requests in 10.08s, 1.68 MB read
@loige
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23. ⛅
Tip 1-bis
Also, find out your ceiling
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24. const { createServer } = require('http')
createServer((req, res) => {
if (req.method === 'GET' && req.url === '/') {
res.writeHead(200, { 'Content-Type': 'text/plain' })
res.end('Hello Worldn')
} else {
res.statusCode = 404
res.end()
}
})
.listen(8080)
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25. autocannon -c 200 --on-port / -- node server.js
Running 10s test @ http://localhost:8080/
200 connections
┌─────────┬──────┬──────┬───────┬───────┬─────────┬─────────┬──────────┐
│ Stat │ 2.5% │ 50% │ 97.5% │ 99% │ Avg │ Stdev │ Max │
├─────────┼──────┼──────┼───────┼───────┼─────────┼─────────┼──────────┤
│ Latency │ 3 ms │ 5 ms │ 11 ms │ 14 ms │ 5.51 ms │ 2.71 ms │ 80.63 ms │
└─────────┴──────┴──────┴───────┴───────┴─────────┴─────────┴──────────┘
┌───────────┬─────────┬─────────┬────────┬─────────┬─────────┬─────────┬─────────┐
│ Stat │ 1% │ 2.5% │ 50% │ 97.5% │ Avg │ Stdev │ Min │
├───────────┼─────────┼─────────┼────────┼─────────┼─────────┼─────────┼─────────┤
│ Req/Sec │ 21087 │ 21087 │ 34623 │ 35487 │ 33258.4 │ 4107.01 │ 21077 │
├───────────┼─────────┼─────────┼────────┼─────────┼─────────┼─────────┼─────────┤
│ Bytes/Sec │ 3.29 MB │ 3.29 MB │ 5.4 MB │ 5.54 MB │ 5.19 MB │ 641 kB │ 3.29 MB │
└───────────┴─────────┴─────────┴────────┴─────────┴─────────┴─────────┴─────────┘
Req/Bytes counts sampled once per second.
333k requests in 10.1s, 51.9 MB read
@loige
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26. autocannon -c 200 --on-port / -- node server.js
Running 10s test @ http://localhost:8080/
200 connections
┌─────────┬──────┬──────┬───────┬───────┬─────────┬─────────┬──────────┐
│ Stat │ 2.5% │ 50% │ 97.5% │ 99% │ Avg │ Stdev │ Max │
├─────────┼──────┼──────┼───────┼───────┼─────────┼─────────┼──────────┤
│ Latency │ 3 ms │ 5 ms │ 11 ms │ 14 ms │ 5.51 ms │ 2.71 ms │ 80.63 ms │
└─────────┴──────┴──────┴───────┴───────┴─────────┴─────────┴──────────┘
┌───────────┬─────────┬─────────┬────────┬─────────┬─────────┬─────────┬─────────┐
│ Stat │ 1% │ 2.5% │ 50% │ 97.5% │ Avg │ Stdev │ Min │
├───────────┼─────────┼─────────┼────────┼─────────┼─────────┼─────────┼─────────┤
│ Req/Sec │ 21087 │ 21087 │ 34623 │ 35487 │ 33258.4 │ 4107.01 │ 21077 │
├───────────┼─────────┼─────────┼────────┼─────────┼─────────┼─────────┼─────────┤
│ Bytes/Sec │ 3.29 MB │ 3.29 MB │ 5.4 MB │ 5.54 MB │ 5.19 MB │ 641 kB │ 3.29 MB │
└───────────┴─────────┴─────────┴────────┴─────────┴─────────┴─────────┴─────────┘
Req/Bytes counts sampled once per second.
333k requests in 10.1s, 51.9 MB read
@loige
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27. 🍾
Tip 2.
Find your bottleneck
@loige
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28. Clinic.js
clinicjs.org
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29. clinic doctor --autocannon [ -c 200 '/?data=Hello%20Shift' ] -- node server.js
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30. clinic flame --autocannon [ -c 200 '/?data=Hello%20Shift' ] -- node server.js
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31. clinic bubble --autocannon [ -c 200 '/?data=Hello%20Shift' ] -- node server.js
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32. 🎳
Tip 3.
Understand your goals
@loige
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33. What do we optimize for?
Throughput?
Memory?
Latency?
@loige
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34. 👁
Tip 4.
Always "observe"
@loige
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35. I mean, in production!
Logs - Metrics - Traces
@loige
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36. 🚀
Tip 5.
Scale your architecture
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37. Performance != Scalability
@loige
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38. How can we scale a system
by adding resources?
@loige
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39. The " "Scale Cube
x-axis
cloning
z-axis
partitioning
y-axis
functional
decomposition
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40. The " "Scale Cube
x-axis
cloning
z-axis
partitioning
y-axis
functional
decomposition
@loige
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41. Cloning
Reverse proxy
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Inside the same server
Load Balancer
Using multiple server
@loige

42. The modulecluster
Master process
Worker
process
Worker
process
Worker
process
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@loige

43. The modulecluster
Master process
Worker
process
Worker
process
Worker
process
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@loige

44. The modulecluster
Master process
Worker
process
Worker
process
Worker
process
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@loige

45. The modulecluster
Master process
Worker
process
Worker
process
Worker
process
32
@loige

46. The modulecluster
Master process
Worker
process
Worker
process
Worker
process
32
@loige

47. The modulecluster
Master process
Worker
process
Worker
process
Worker
process
32
@loige

48. The modulecluster
Master process
Worker
process
Worker
process
Worker
process
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@loige

49. const cluster = require('cluster')
const numCPUs = require('os').cpus().length
if (cluster.isMaster) {
// Fork workers
for (let i = 0; i < numCPUs; i++) {
cluster.fork()
}
} else {
// Worker code
require('./server.js')
}
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50. const cluster = require('cluster')
const numCPUs = require('os').cpus().length
if (cluster.isMaster) {
// Fork workers
for (let i = 0; i < numCPUs; i++) {
cluster.fork()
}
} else {
// Worker code
require('./server.js')
} 3-4x req/sec
(8 core)
@loige
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51. You could also use
Check out !
Worker Threads
piscina
@loige
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52. Cloning is the easiest strategy to
scale a service...
... as long as your application is
Stateless
@loige
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53. API Gateway
Functional decomposition
a.k.a. "Micro-services"
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/products
/cart
cart DB
products
DB
@loige

54. API Gateway
Functional decomposition
a.k.a. "Micro-services"
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/products
/cart
Functional decomposition can
also be combined with cloning!
cart DB
products
DB
@loige

55. Node.js is great for microservices
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56. Microservices can also help with
scaling the organisation!
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57. Microservices add complexity
Observability
Deployments
Versioning
Integration
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58. Partitioning
Service and Data Partitioning along Customer Boundaries
Shard partitioning
/products/[A-L]/
/products/[M-Z]/
DB 2
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DB 1
@loige

59. Partitioning is generally used
to scale databases
and
SaaS software geographically
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60. Summary
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61. Summary
🛫 Establish a baseline
@loige
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62. Summary
🛫 Establish a baseline
🍾 Find your bottleneck
@loige
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63. Summary
🛫 Establish a baseline
🍾 Find your bottleneck
🎳 Understand your goals
@loige
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64. Summary
🛫 Establish a baseline
🍾 Find your bottleneck
🎳 Understand your goals
👁 Always "observe"
@loige
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65. Summary
🛫 Establish a baseline
🍾 Find your bottleneck
🎳 Understand your goals
👁 Always "observe"
🚀 Scale your architecture
(cloning, decomposition & partitioning)
@loige
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66. Thank you!
Special thanks to ,
, ,
, ,
, ,
, ,
, , ,
, , ,
, , ,
, , ,
Icons and SVGs by
@StefanoAbalsamo
@matteocollina @dagonzago
@NullishCoalesce @DublinSvelte
@KViglucci @gjohnson391
@lucamaraschi @laurekamalandua
@giltayar @mrm8488 @adrirai
@harafise @EugeneWare @Jauny
@tlivings @michaelcfine @leojino
@shahidontech @Lordoomer @zsadigov
@dottorblaster
freepik.com
loige.link/node-scale
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