The document discusses strategies for building a scalable SaaS application using CoreOS and etcd, emphasizing goals such as reducing application complexity, A/B testing, and minimizing DevOps efforts. It highlights the importance of etcd as a real-time infrastructure state database and covers service discovery, dynamic external services, and deployment methodologies. Closing thoughts reflect on the benefits of containers, the efficacy of CoreOS, and the impending prominence of Kubernetes.

1. @RossKukulinski
Building a SaaS with
CoreOS and etcd
CoreOS Fest
May 4, 2015

2. @RossKukulinski
Ross Kukulinski
Yodlr Founder / CEO
BayNode Co-Organizer
iojs/nodejs Evangelist
Soccer Fanatic
ross@getyodlr.com

4. @RossKukulinski
The internal tool that wasn’t
internal anymore

5. @RossKukulinski
Our Goals
• Reduce application complexity
• A/B test multiple versions of apps
• Consistent app from dev → test → staging → prod
• Scalable
• Fault tolerant
• Minimize time spent doing ‘devops’

6. @RossKukulinski
Docker

7. @RossKukulinski
Our Goals
• Reduce application complexity
• A/B test multiple versions of apps
• Consistent app from dev → test → staging → prod
• Scalable
• Fault tolerant
• Minimize time spent doing ‘devops’

8. @RossKukulinski
How do you ship
Docker containers?

9. @RossKukulinski
Linux for Massive Server Deployments

10. @RossKukulinski
Goals
• Reduce application complexity
• Run multiple versions of the same app
• Consistent app from dev → test → staging → prod
• Scalable
• Fault tolerant
• Minimize time spent doing ‘devops’

11. @RossKukulinski
After further deliberation, we’re going big
and switching to CoreOS/Docker entirely.
We feel its the right direction long-term for
us and application development in general.
- Me, internal memo
September 2014

12. Lightbulb! by Matthew WynnMonitor photo by Don Fulano

13. @RossKukulinski
1. etcd is a database
So treat it like one

14. @RossKukulinskiImage: CoreOS.com
Give etcd space

15. @RossKukulinski
2. etcd is a database
For your real-time infrastructure state

16. @RossKukulinski
Service Availability
REST API
microservice
Sidekick
Sidekick Pattern:
1. Get ip:port of microservice (docker inspect)
2. Health checks (containerized integration tests)
3. Publish service instance details to etcd
etcd
1 & 2 3

17. @RossKukulinski
Service Discovery
haproxy confd
Confd:
1. Query etcd for ip:port of upstream services
2. Update configuration from template
3. Reload load balancer process
etcd
github.com/kelseyhightower/confd
2 & 3 1

18. @RossKukulinski
Dynamic external services
DNS & Cloud
Load Balancers
lb-config
lb-config:
1. Query etcd for domain/ip:port of internal lbs
2. Update DNS & external load balancers
etcd
12
github.com/yodlr/rax-lb-config

19. @RossKukulinski
3.

20. @RossKukulinski
3. etcd is a database
With super important data: Protect it!
PSA: $private_ipv4 is probably not what you think it is

21. @RossKukulinski
4. Sometimes you just need a GUI
(Docker & CoreOS do have awesome CLI tools though)

22. github.com/yodlr/CoreGI
Also check out purpleworks/fleet-ui

23. @RossKukulinski
5. Fleet unit templates aren’t enough
rest-api@.service
rest-api@{1..3}.service —> 3 instances of the service

24. @RossKukulinski
rest-api-{{env}}-{{tag}}@.service
github.com/yodlr/fleet-templater

25. @RossKukulinski
rest-api-prod-86a951a9@.service
github.com/yodlr/fleet-templater

26. @RossKukulinski
App deploys
before
Kubernetes

27. @RossKukulinski
Rolling Deploys as a Service
github.com/yodlr/fleet-rolling-deploys

28. @RossKukulinski
Closing thoughts
• Containers are awesome
• We <3 CoreOS
• You can get really far with fleet & etcd
• Kubernetes is so close to primetime
• Remember: etcd is a database, treat it like one

29. @RossKukulinski
Thanks!
ross@getyodlr.com