Docker swarm
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This document discusses Microservices and Docker Swarm. It begins by introducing the presenter and their background. It then defines what a microservice is and introduces Docker. Key concepts about Docker Swarm are explained such as swarm features, service discovery without an external database, and the swarm concept of managers, workers, services and tasks. It demonstrates how to build a swarm cluster and add nodes, and discusses security, routing mesh, scaling, reverse proxy, rolling updates and secrets. Finally it briefly mentions logging, metrics and dashboard tools to monitor Docker systems.
Docker swarm
- 1. Microservices and Docker Swarm
- 2. Who am I? Alberto Guimarães Viana Goiano, atualmente moro em Hamburg/Alemanha E-mail: [email protected] Twitter: @albertogviana Github: https://github.com/albertogviana
- 5. What is a microservice? ■ Small, and Focused on Doing One Thing Well ■ Autonomous Building Microservices by Sam Newman
- 6. Docker
- 7. Docker ecosystem ■ Docker Engine ■ Docker Swarm ■ Docker Registry ■ Docker Machine ■ Docker Compose
- 8. Docker Swarm
- 9. Swarm Features ■ Highly-available, distributed store based on Raft (Service discovery) ■ Cluster management integrated with Docker Engine ■ Declarative service model ■ Scaling ■ Desired state reconciliation ■ Multi-host networking ■ Load balancing ■ Secure by default ■ Rolling updates
- 10. Service Discovery ■ All other orchestration systems use a key/value store (k8s→etcd, nomad→consul, mesos→zookeeper, etc.) ■ Swarm stores information directly in Raft ■ Analogy courtesy of @aluzzardi: It's like B-Trees and RDBMS. They are different layers, often associated. But you don't need to bring up a full SQL server when all you need is to index some data. ■ As a result, the orchestrator has direct access to the data (the main copy of the data is stored in the orchestrator's memory) ■ Simpler, easier to deploy and operate; also faster
- 11. Swarm concept ■ A node can be a manager or a worker ■ A manager actively takes part in the Raft consensus ■ You can talk to a manager using the Swarm API ■ One manager is elected as the leader; other managers merely forward requests to it ■ Using the API, you can indicate that you want to run a service
- 12. Swarm concept ■ A service is specified by its desired state: which image, how many instances... ■ The leader uses different subsystems to break down services into tasks: orchestrator, scheduler, allocator, dispatcher ■ A task corresponds to a specific container, assigned to a specific node ■ Nodes know which tasks should be running, and will start or stop containers accordingly (through the Docker Engine API)
- 14. Swarm Mode ■ Docker Engine 1.12 features SwarmKit integration ■ The Docker CLI features three new commands: ○ docker swarm (enable Swarm mode; join a Swarm; adjust cluster parameters) ○ docker node (view nodes; promote/demote managers; manage nodes) ○ docker service (create and manage services)
- 17. Adding nodes to the cluster
- 18. Security
- 19. Under the hood ■ When we do docker swarm init, a TLS root CA is created. Then a keypair is issued for the first node, and signed by the root CA. ■ When further nodes join the Swarm, they are issued their own keypair, signed by the root CA, and they also receive the root CA public key and certificate. ■ All communication is encrypted over TLS. ■ The node keys and certificates are automatically renewed on regular intervals (by default, 90 days; this is tunable with docker swarm update).
- 20. Docker Service
- 21. Routing Mesh
- 22. Routing Mesh
- 24. Reverse Proxy
- 25. Dockerfile
- 26. Rolling Updates
- 27. Docker secret
- 28. Docker Node
- 29. Docker system?
- 30. What now?
- 31. Metrics ■ Prometheus ■ cAdvisor ■ InfluxDB
- 32. Logging ■ ElasticSearch, Kibana and Logstash (ELK) ■ FluentD ■ Loggly ■ Graylog ■ gliderlabs/logspout
- 34. Book