Run high-available web-application in the Cloud on Docker Swarm Mode. The latest Docker Engine version (1.12+) comes with interesting features that streamline setting-up new cluster and maintenance tasks for Ops. Throughout the talk engineers will learn how to set up a new Docker Swarm cluster, scale in and out and make nodes join and leave cluster in automated fashion. Furthermore single region and multi-region cluster scenarios will be discussed.

1. LB+HA webapp with Docker Swarm
Simone Soldateschi
ROME - APRIL 13/14 2018

2. “Let me tell you a story...”

3. Who I am
● Staff Engineer at Slack
● Previously at Microsoft,
Rackspace
● 10+ years of experience as
○ Software Engineer
○ Systems Engineer
○ DevOps'in for the last 8 years
Simone Soldateschi
@soldasimo
simone.soldateschi@gmail.com
Friday: 5.50pm-6.30pm
+ during breaks

4. ● Container Orchestration Engines, COEs
● Docker Swarm Mode, why
● Cloud Infrastructure, abs
● Service Management, how
Agenda

5. Container Orchestration
Engines

6. COEs
- Lots of features (auto-
scaling, secrets
management, UI)
- YAML deployment
model
- Pods
- Large community
- Google, Red Hat, Azure
- Quite recent project
- YAML deployment model
- Multi-master
- Auto-healing
- TLS network security
- Quick and Easy
- No UI
- No auto-scaling
- No external load-
balancing
- Multi-master
- Highly scalable
- Multi OSes
- Steep learning curve
- Airbnb, ~Apple, eBay,
Netflix, Twitter

7. Docker Swarm Mode

8. The path to Docker Swarm Mode
«If you are using a Docker version prior to 1.12.0,
you can use standalone swarm,
but we recommend updating.»
https://docs.docker.com/engine/swarm/

9. Standalone Swarm != Swarm mode
$ docker swarm init
$ docker swarm join

10. Key Features
● Cluster management with Docker Engine
● Declarative service model
● Auto Scaling
● Multi-host networking
● Service Discovery
● Load balancing
● Secure by default (TLS)
● Rolling updates
● Developer oriented

11. Docker Swarm Security

12. Cloud Infrastructure

13. Manager initialises cluster
docker swarm init
--advertise-addr $MANAGER_IP
Stand up basic cluster
[Manager|Worker]
docker swarm join
--token $TOKEN_[MANAGER|WORKER]
$MANAGER_IP:2377

14. Infrastructure as Code
template PRplan
plan destroyapply
DEV
DEPLOY

15. Basic Cluster

16. Architecture
Raft
Internal Distributed Store
Leader
Follower
Follower
Workers Gossip network
Raft consensus groupManagers

17. The Raft Consensus Algorithm
The Secret Lives of Data

18. Raft consensus
Given N managers:
● Raft tolerates up to (N-1)/2 failures.
● Raft requires a quorum of (N/2)+1 members to agree
on values proposed to the cluster.

19. Cluster Fault Tolerance

20. Multi AZ

21. Scale Cluster in/out
manager ASG
worker ASG

22. Docker Swarm cluster revised
Manager
docker swarm join
--token $TOKEN_MANAGER
$MANAGER_IP:2377
Worker
docker swarm join
--token $TOKEN_WORKER
$MANAGER_IP:2377

23. Autojoin Swarm Nodes

24. Autojoin Swarm Nodes
1. Ask manager for a token,
e.g. API, SSH
3. Join with token
2. Fetch token

25. Autojoin Swarm Nodes
1. Ask Vault for
a token
2. Fetch token
3. Join with token

26. Service Management

27. stack
Container, Service and Stack
service
container

28. A day in the life of a Docker Service
create scale rm
ls
logs rollback
ps
update
?
?
inspect

29. $ docker service create --name web -p 80:80 nginx
overall progress: 1 out of 1 tasks
1/1: running [=================================>]
verify: Service converged
Docker service
$ docker service scale web=3
web scaled to 3
overall progress: 3 out of 3 tasks
1/3: running [=================================>]
2/3: running [=================================>]
3/3: running [=================================>]
verify: Service converged
$ docker service rm web

30. A day in the life of a Docker Stack
deploy services rm
ls
?
ps

31. Docker Stacks
version: "3"
services:
web:
image: nginx
deploy:
replicas: 3
resources:
limits:
cpus: "0.1"
memory: 50M
restart_policy:
condition: on-failure
ports:
- "80:80"
networks:
- webnet
networks:
webnet:
$ docker stack deploy -c docker-compose.yml webstack
Creating network webstack_webnet
Creating service webstack_web
$ docker stack ps --format
"{{.Name}}: {{.Image}} {{.Node}}
{{.DesiredState}}"
webstack
webstack_web.1: nginx:latest worker2 Running
webstack_web.2: nginx:latest manager Running
webstack_web.3: nginx:latest worker1 Running

32. Docker Stacks
$ docker service scale webstack_web=6
webstack_web scaled to 6
overall progress: 6 out of 6 tasks
1/6: running [===================================>]
2/6: running [===================================>]
3/6: running [===================================>]
4/6: running [===================================>]
5/6: running [===================================>]
6/6: running [===================================>]
verify: Service converged

33. Secrets Management
● It’s best not to have secrets.
● Don’t write secrets down.
● Protect secrets in one place.

34. Secrets Management
manager
TLS
Internal distributed store
manager
TLS
manager
TLS
Service Deploy
worker
TLS
worker
TLS
worker
TLS
Raft Consensus Group

35. Multi-region
Cloud Infrastructure

36. Multi-region

37. Pilot Light

38. Tie up all things
// wait for it...

39. Demo Time
● Stand up development Swarm cluster
● Start services
● Start monitoring
● Scale and Load-test

40. Stand up Dev Swarm cluster
$ git clone
https://github.com/siso/vagrant-docker-swarm.git
$ cd vagrant-docker-swarm
$ AUTO_START_SWARM=true vagrant up

41. Scale and Load-test

42. Monitor load-tests

43. Q&A

44. simone soldateschi
Friday: 5.50pm-6.30pm
+
during breaks
@soldasimo
simone.soldateschi@gmail.com
github.com/siso/vagrant-docker-
swarm

45. Recap

46. ● Services and Stacks
Recap
● Swarm Mode
● Multi-region infrastructure
● Provision Infrastructure
● Demo

47. Lesson Learned
● Options are good. Many COEs to choose from.
● Docker Swarm Mode is great for greenfield project.
● Prototype, then automate. Don’t do both.

48. Thank You!

49. Extras

50. References
● vagrant-docker-swarm on github
Vagrantfile to stand up Docker Engine Swarm Mode cluster. It requires Docker 1.12+, and runs Debian.
● swarmprom
Docker Swarm instrumentation with Prometheus, Grafana, cAdvisor, Node Exporter and Alert Manager
● Raft - Understandable Distributed Consensus
● Swarm mode overview

51. License
Attribution-ShareAlike 4.0
International