Embed Size (px)
DESCRIPTION
Slides for the presentation at the nodeconf.eu conference in Waterford, Ireland on Sept 8, 2014.
Citation preview
About me
Dejan Glozic, Full-Stack Architect
IBM Canada Toronto Laboratory
@dglozic
http://dejanglozic.com
Disclaimer: I don’t speak for the entire IBM
Just my cozy corner in IBM Rational
Our storyWhy we chose micro-services and Node.js
–Gerrald Mast, The Comic Mind: Comedy and the Movies, 1973
Boy meets girl, boy looses girl, boy recovers true love.
The new cliché• Boy builds a monolith quickly (because MVP)
• Boy bloats the monolith with features
• Boy makes a big ball of mud
• Boy rewrites the system using small services
• Boy cannot shut up about it at conferences
We used micro-services before they were cool
We just called them ’12-factor apps’.
1 4 12CONCEPT TENETS FACTORS
Our first Node.js service
We needed a good enough reason
We were sitting on the fenceI have a blog post to prove it
What made us bite the bullet?
NodeSummit 2013 - Walmart, Groupon, PayPal, Yahoo
It is not hard to build one app
For two or more, you need an actual architecture
Our key tenets
1. Many micro-services instead of a monolith
2. Deploy micro-services independently
3. Communicate using message queues
4. Cluster locally
1. Many micro-services
Down with the monolith!
We used to build monoliths
Practically a must on-premise
The cloud changed everything
Bizarro world - everything good on premise is bad in the cloud
Borg collectiveBreak a large system into manageable chunks. Say,
using Node.js.
Small services are Node.js’ sweet spot
There is a reason for the hexagon icon (you know, bee hive?)
Monolith antibodiesIt takes a gigantic effort NOT to arrive at a micro-service
system using Node.js
Node.js is a great candidate
• Miserly on the resources
• Component model + NPM
• Great test and build tools (e.g. JSHint, Mocha, Grunt)
• Easy to write (and completely rewrite)
2. Deploy micro-services independently
No maintenance downtime
No budget for big outages
Need to fix and evolve the system in mid-flight
Node.js is a great candidate
• Services start and stop in seconds
• Tools to keep the services up (e.g. PM2)
• PaaS-friendly (we use Bluemix)
• Clustering is great for rolling deploys
3. Message brokersBecause there is life beyond REST
REST uses request/response pattern
This makes micro-service systems too ‘chatty’.
Test: review firewall rules
The more IPs listed, the chattier the service.
Alternative: event collaboration
State changes are published into topics, interested services subscribe to them.
Advantages• No wasted requests (are we there yet?)
• Resiliency (fire and forget)
• Safety valve
• Loose coupling of services
• Enables server push
Messaging exampleRabbitMQ between micro-services, WebSockets for
server push
Node.js is a great candidate
• Great support for MQ protocols (MQTT, AMQP)
• Async processing of incoming messages
• Great support for WebSockets (server push)
4. Local clusteringBecause load is rarely uniform
Concerns
• Apply extra capacity where it matters
• Evolve the system as needed
• Vertical vs horizontal scaling
• HA vs scaling
Node.js is a great candidate
• Single threaded event loop
• ‘Share nothing’ from day 1
• Local clustering to use multiple cores
• Load balancing across VMs for horizontal scaling
MQ clusteringRabbitMQ worker queue, round-robin to micro-service
workers
Truth in advertisingOther people develop micro-services using Java/Netty or
Scala/Akka or Go
Node.js is (still) a great candidate
• Browsers running JS give Node.js an edge
• Express or Hapi make API services easy
• NoSQL DBs with JSON (JS all the way down)
• Developer happiness
(More) Truth in advertising
We have some battle scars to show
Legal hates usYou want us to vet how many modules again?
Ops hate usYou need how many VMs, again?
We get PaaS now Luckily we can move from SoftLayer we own to Bluemix
we also own.
SSO is hard Nontrivial to make a federated system secure yet
transparent.
Composition is hard Stitching a page from several micro-services is non-
trivial (yeah, yeah, Web Components HTML Imports…)
We have no regretsAs Ralph Wiggum would say, “We are learnding!"
Questions?
