Clustering with
@MichielDeMey
Full Stack Engineer at Storied
Clustering
Process Clustering
using Node.js Cluster Module
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Container and Server Clustering
using Kubernetes
Node.js Cluster Module
Server
> Node
Server
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> Node
> Node
> Node
> Node
Node uses only a single process (one CPU) and a mamximum of 1.5GB of RAM
Node.js
Cluster Module
Take advantage of multi-core systems.
1 master process forks n workers.
Node.js cluster module will load-balance instances of your app to available CPUs.
Can communicate with the parent using IPC.
There is no shared state between workers.
var cluster = require('cluster')
var app = require('./server')
if (cluster.isMaster) {
var numCPUs = require('os').cpus().length
for (var i = 0; i < numCPUs; i++) {
cluster.fork(process.env)
}
} else {
app.listen(process.env.PORT)
}var app = require('express')()
app.get('/ping', function(req, res) {
res.send('pong!')
})
module.exports = app
var cluster = require('cluster')
var app = require('./server')
if (cluster.isMaster) {
var numCPUs = require('os').cpus().length
for (var i = 0; i < numCPUs; i++) {
cluster.fork(process.env)
}
} else {
app.listen(process.env.PORT)
}The Cluster module â
Fork children â
Handle requests â
var app = require('express')()
app.get('/ping', function(req, res) {
res.send('pong!')
})
module.exports = app
Your average Express server
Export for better maintainability â
var cluster = require('cluster')
var app = require('./server')
if (cluster.isMaster) {
var numCPUs = require('os').cpus().length
for (var i = 0; i < numCPUs; i++) {
cluster.fork(process.env)
}
} else {
app.listen(process.env.PORT)
}What about worker crashes?
cluster.on('exit',
function (worker, code, signal) {
cluster.fork(process.env)
}
)Container Clustering
> Node
Server
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> Node
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Distribute load over multiple (virtual or physical) machines
Microservices
Move away from the monolithic app design.
Services talk to each other using APIs and industry standard protocols.
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REST API
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What about authentication?
Our services are stateless, authentication should also be stateless.
Session
Store
Service
Service
Service
Using centralized session store.
Application state = hard to scale
What about authorization?
Our services are decentralized, authorization should also be decentralized.
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Forget about session-based authentication and let's talk about token based authentication.
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/user/me
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/photos
JSON Web Token
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJkZS5tZXkubWljaGllbEBnbWFpbC5jb20iLCJpc3MiOiJhdXRoLmRlbWV5LmlvIiwicGVybWlzc2lvbnMiOlsicGluZyIsInBvbmciXX0.yj84-dz1D1HoJQjehsjHQPm7m60FtCM8pi87MaI5eUE
JSON Web Token
- Holds your identity
- No expensive DB lookups every time
- Perfect for clustering
- Can use symmetric/asymmetric keys
Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJkZS5tZXkubWljaGllbEBnbWFpbC5jb20iLCJpc3MiOiJhdXRoLmRlbWV5LmlvIiwicGVybWlzc2lvbnMiOlsicGluZyIsInBvbmciXX0.yj84-dz1D1HoJQjehsjHQPm7m60FtCM8pi87MaI5eUE
Authenticate using HTTP header
Similar to oAuth specification
Kubernetes by Google
Getting started
- Master
- API Server
- Scheduler
- Controller Manager
- Node
- Kubelet
- Kube-proxy
Getting started
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Pods
- Collection of containers with shared volumes.
- Always on the same Node
- Replication Controllers
- A replication controller ensures that a specified number of pod "replicas" are running at any one time
- Services
- Pod are born and die. Services provide a consistent, well known endpoint for a set of pods
- Labels
- Key-value pairs attached to K8s resources
Demo Architecture
- Reverse Proxy Service
- Authentication Service
- Ping Service
Clustering with Node.js
By Michiel De Mey
Clustering with Node.js
Let's talk about clustering in Node.js, the Node.js cluster module and Container Clustering.
