Microservices at Netflix have evolved over time from a single monolithic application to hundreds of fine-grained services. While this provides benefits like independent delivery, it also introduces complexity and challenges around operations, testing, and availability. Netflix addresses these challenges through tools like Hystrix for fault tolerance, Eureka for service discovery, Ribbon for load balancing, and RxNetty for asynchronous communication between services.

1. MicroServices at NETFLIX
Best Practices & Tools of the trade
Sudhir Tonse
Manager, Cloud Platform
@stonse
http://linkedin.com/in/sudhirtonse
Nitesh Kant
Platform Architect
@NiteshKant
http://linkedin.com/in/niteshkant

2. ● Old DataCenter
(2008)
● Everything in
one WebApp
(.war)
● AWS Cloud
(2012)
● 100s of Fine
Grained
Services

3. Positives
● Isolation brings better Availability*
● Independent Speed of Delivery (by different
teams)
● Decentralized Governance (DevOps)

4. Challenges
Distributed Systems are inherently Complex
Operational Overhead (100s of services; DevOps model absolutely required)
Service Interface Versioning, Mismatches?
Testing (Need the entire ecosystem to test)
Fan out of Requests -> Increases n/w traffic

5. Claim
MicroServices increase your overall availability

6. True?
Yes … but wait!

7. One missing “;” brought down ALL
of Netflix

8. Introduced MicroServices ...

9. Uptime SLA
Assume a Monolithic Service with 99.99%
availability
What if you have ...
~30 Microservices (each with 99.99% SLA)??

10. Reality
One rogue (dependency) micro service CAN
bring your whole site down!

11. How?

12. Service Hosed!!

13. Combined Effective SLA (Availability)
== 2 HOURS of downtime per month
== 99.7 % uptime!!

14. But what if I want better?
MicroServices does not automatically mean
better Availability
- Unless you have Fault Tolerant
Architecture

15. Guard your Service!
Use Hystrix (http://github.com/netflix/hystrix)

16. Service Discovery & Loadbalancers
Choice
1. Central Loadbalancer? (H/W or S/W)
OR
2. Client based S/W Loadbalancer?

17. Client based Smart Loadbalancer
Use Ribbon (http://github.com/netflix/ribbon)

18. Tools of the Trade
OR

19. Service Dependency View

20. Distributed Tracing

21. Chattiness (and Fan Out)
~2 Billion Requests per day on Edge Service
…
Results in ~20 Billion Fan out requests in ~100
MicroServices

22. Fan out

23. IPC 2.0 .. the next frontier
@NiteshKant

24. Netflix IPC Stack (1.0)
A
p
a
c
h
e
H
T
T
P
C
l
i
e
n
t
Eureka (Service Registry)
Server (Karyon)
Apache
Tomcat
Client
H
y
s
t
r
i
x
E
V
C
a
c
h
e
Ribbon
Load
Balancing
Eureka
Integration
Metrics
(Servo)
Bootstrapping (Governator)
Metrics (Servo)
Admin ConsoleHTTP
Eureka Integration
Registration
Fetch Registry

25. Netflix IPC Stack (2.0)
Client (Ribbon 2.0)
Eureka (Service Registry)
Server (Karyon)
Ribbon Transport
Load
Balancing
Eureka
Integration
Metrics
(Servo)
Bootstrapping (Governator)
Metrics (Servo)
Admin Console
HTTP
Eureka Integration
Registration
Fetch Registry
Ribbon
Hystrix
EVCache
R
x
N
e
t
t
y
RxNetty
UDP
TCP
WebSockets
SSE

26. Synchronous Applications
Tomcat
Connector Application code Hystrix
Apache HTTP
Client
Conn 1Thread 1 Thread 1’
Thread
1*
Thread 1’
Conn 2Thread 2 Thread 2’
Thread
2*
Thread 2’
Conn nThread n Thread n’
Thread
n*
Thread n’
……....
*If there isn’t any application driven thread change

27. Synchronous Applications
Tomcat
Connector Application code Hystrix
Apache HTTP
Client
Conn 1Thread 1 Thread 1’
Thread
1*
Thread 1’
Conn 2Thread 2 Thread 2’
Thread
2*
Thread 2’
Conn nThread n Thread n’
Thread
n*
Thread n’
……....
Large # of connections / Large # of external dependencies => tons of threads.
*If there isn’t any application driven thread change

28. Asynchronous applications
Application code RxNettyHystrixRxNetty
Eventloop 1 Eventloop 4
Eventloop 1*
Eventloop 4*
*If there isn’t any application driven thread change
“N” connections per eventloop
Request processing in Eventloop
Hystrix used for throttling not for achieving asynchronicity.
Eventloops are shared between In & OUT

29. Asynchronous Applications
Application code RxNettyHystrixRxNetty
Eventloop 1 Eventloop 4
Eventloop 1*
Eventloop 4*
*If there isn’t any application driven thread change
Eventloop 2 Eventloop 3
Eventloop 1*
Eventloop 4*
……....
Eventloop 4 Eventloop 1
Eventloop 1*
Eventloop 4*
# of processors => # of eventloops. No dependence on # of connections

30. Takeaway
MicroServices is a better architecture
compared to Monolithic Apps
However
Beaware of the challenges - Use Best Practices
and battle-tested OSS components

31. http://netflix.github.co