Clustering with Docker Swarm
Alexander Zeitler
@alexzeitler_
alexander.zeitler@pdmlab.com
Docker ecosystem
Docker Engine
Docker Compose
Docker Machine
Docker Swarm
Docker Hub
Docker Registry
Docker Cloud
Swarm
- Native (from Docker, Inc.)
- Clusters Dockers hosts in a large pool
- Simplified management at scale
Alternatives
- Kubernetes
- Mesosphere
- Apache Mesos
- ...
Docker Architecture
Client / Server
Docker Server
(Daemon)
Docker Client
(CLI)
TCP 2375/76
Docker API ≈ Swarm API
Scaling is hard
Scaling with Swarm
Swarm Manager
- Cluster administration
- Executes Docker commands
- HA possible
- 1 Primary
- n Secondaries
Discovery Service
- Key/Value store
- Cluster config / state
- Mandatory for Swarm
- HA possible
- Rebuild
- Swarm
- !Network
- Consul
- etcd
- ZooKeeper
Swarm Manager
Discovery Service
P
P
P
S
S
S
S
P
P
S
P
P
P
S
S
S
S
P
P
S
Filtering - e.g. "Production"
Filtering
Affinity
- Image
- Container
Constraint
- Standard
- docker info
-
Custom
- tagged daemons
- VPC, AZ
- Blue/Green
- etc.
Resource
Availability of
Resources
- Network
- RAM
- CPU
- etc.
P
P
P
S
S
S
S
P
P
S
Scheduling
Scheduling
Random
- Debugging
- Production?
BinPack
CPU/RAM
- !Spread
- Smallest node first
- Stopped containers considered
- Use as less infrastructure as possible
- Production!
Spread
CPU/RAM
- Default
- Balanced deployment (if CPU/RAM is ok)
- Daemon with the least containers first
- Stopped containers considered
- Production!
Scheduling
One Strategy / Swarm Cluster
Building the Infrastructure
HA for Swarm Manager
Put it in different VMs
Put VMs in different Hosts
Put Hosts in different Racks
Connect Hosts to different Access Layer Switches
Put Racks in different Halls / DC
Avoid single points of failure
Swarm Manager
Discovery Service
Client / CLI
3375/76
2376
8500
2376
8500
Node 1
Node 2
Node 3
Demo
Questions
Thanks!
Clustering with Docker Swarm
By Alexander Zeitler
