Transcript
Adventures with
micro-ServicesMohit Thatte (@mohitthatte)
Anand Agrawal (@anand_agrawal)
ThoughtWorks Inc.
Enough about us. What’s in it for you?
What?Why?How?When?
What are micro services?services?micro
What are micro services?
services?
micro
What are micro services?
A real thing that does some thing!
services?
micro
What are micro services?
A real thing that does some thing!Implementation Contract
services?
micro
What are micro services?small independent composable
servicesthat do one thing well
Unix philosophyWrite programs that do one thing well.
Write programs that work together.
cat | grep | sed | awk | ...
HTTP is the new pipe!
Single responsibility
Low coupling, high cohesion
Small, well defined interfaces
Object Oriented philosophy
use micro services?Why we
Once upon a time...
lots of legacy, no reuse
not flexible, high cost of change
no one knows how it works
concentrated complexity
90 year old business
lots of legacy, no reuse
not flexible, high cost of change
no one knows how it works
concentrated complexity
independent small that do one thingcomposable
90 year old business
“A 100k loc app is just 100 1k loc appswaiting to happen”
- Jeff Bay
Adventure so far
25 VM’s in production
10 micro-services
one click deployment
60+ VM’s across environments
µService
DB
µService
DB
µService
DB
µService
DB
How did we start?
Solve small, valuable problems
Start with high level services
When a service starts doing too much, extract a smaller one
Orders PaymentsCustomersCatalog(Games)
Orders PaymentsCustomers
Legacy
Catalog(Games)
Orders PaymentsCustomers
Legacy Order Processing
Catalog(Games)
Orders PaymentsCustomers
Legacy ResultsOrder Processing
Catalog(Games)
Looks like plain old services, what makes them ‘micro’?
single responsibility
1 service = 1 ‘resource’(maybe 2!)
I can haz code of conduct?
respect service boundaries
focus on contracts
avoid coupling
extract cross cutting concerns
Orders PaymentsCustomers
Communications
Legacy ResultsOrderProcessing
ScheduledJobs
Errorreporting
Catalog(Games)
So many repos, how do you stay productive?
automate, automate, automate...
DevOps #ftw
15 minute dev box setup
spin up a new service in minutes*
Vagrant + Puppet = AWESOME!
feature toggles over branches
client gems
Is that all captain?
add health checks + circuit breaker
loggingcan you trace a request through?
Avoid / Defer
versioning services
manual tinkering on VM’s
How do I make a changeand still stay sane?
Test It!
Unit Tests
Contract Testsis my service doing what it should?
out of container
strictly black box
Integration Testsare all my services playing nicely together?
testing distributed effects
testing async actions
Continuous Integration
IntegrationTests UAT Performance
Production
ServiceTests
Ok, so you tested it, now release it!
Step 1: Set up ze VM’s
Puppet Solo + SSH in a loop
Puppet goes through CI just like app code
Our ideal : ImmutableServer
deploy all or nothing
Step 2: Deploy ze code
Continuous Integration
IntegrationTests UAT Performance
Production
ServiceTests
CI + DevOpsenables
single-click deployment
so easy, our product owner does it!
it just works™
3 mins to production (~25 servers)
“we’re effectively pushing the complexity from the application
into the infrastructure...”- James Lewis
When to use micro-services?
Tradeoffs
benefit cost
small units of reuse/maintain complex infrastructure
grow independently learning curve
scale independently network overhead
independent DB fragmented data
Polyglot
Thanks!
Questions?
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