Introduction to docker swarm
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This document provides an introduction to Docker Swarm, which allows multiple Docker hosts to be clustered together into a single virtual Docker host. It discusses key components of Docker Swarm including managers, nodes, services, discovery services, and scheduling. It also provides steps for creating a Swarm cluster, deploying services, and considering high availability and security aspects.
Introduction to docker swarm
- 1. Walid AshrafResearcher , Software Developer, Instructor about.me/WalidAshraf INTRODUCTION TO DOCKER SWARM
- 2. Docker Swarm - Walid Ashraf Docker Basic Architecture Native Client UCP Third party
- 3. Docker Swarm - Walid Ashraf INTRODUCTION TO DOCKER SWARM
- 4. Docker Swarm - Walid Ashraf
- 5. Docker Swarm - Walid Ashraf What is Swarm Docker Swarm is native clustering for Docker. • It turns a pool of Docker hosts into a single, virtual Docker host. Docker Swarm serves the standard Docker API, any tool that already communicates with a Docker daemon can use Swarm to transparently scale to multiple hosts.
- 6. Docker Swarm - Walid Ashraf
- 7. Docker Swarm - Walid Ashraf Docker Discovery Service A key Value store for configurations Defaults to a hosted discovery service with Docker Swarm. The service maintains a list of IPs in your cluster. This page describes the different types of hosted discovery available to you. Discovery service replacements (Libkv abstraction): • Consul • Etcd • ZooKeeper Should be replicated
- 8. Docker Swarm - Walid Ashraf Swarm Manager It’s the cluster admin or master All communications with nodes passes through it Supports HA • 1 Primary (the Actual Admin) • Multiple Secondary Managers (Transfers to primary) • In case of primary failure (leader election occurs)
- 9. Docker Swarm - Walid Ashraf How this works The Manager deploys the required services (Containers) to a host(s) based on the configurations. The Manager checks with the discovery service for available nodes The Client Issue a command to the swarm manager
- 10. Docker Swarm - Walid Ashraf Filtering: The ability to mask some of the nodes Constraints •node to refer to the node by ID or name •storagedriver •executiondriver •kernelversion •operatingsystem Resources •Containerslots Number of containers on a host •Port Containers •Affinity filters •container name or id •an image on the host •a custom label applied to the container •Depencecy
- 11. Docker Swarm - Walid Ashraf Scheduling Random Spread • Default • Least no of containers • CPU and RAM aware Binpack • Most no of containers • CPU and RAM aware
- 12. Docker Swarm - Walid Ashraf CREATING SWARM INFRASTRUCTURE
- 13. Docker Swarm - Walid Ashraf 1 – Create Master docker swarm init --advertise-addr <MANAGER-IP> $ docker swarm init --advertise-addr 192.168.99.100 docker info Swarm: active NodeID: dxn1zf6l61qsb1josjja83ngz Is Manager: true Managers: 1 Nodes: 1 docker node ls ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS dxn1zf6l61qsb1josjja83ngz * manager1 Ready Active Leader
- 14. Docker Swarm - Walid Ashraf 2 – Add Nodes $ docker swarm join --token SWMTKN-1- 49nj1cmql0jkz5s954yi3oex3nedyz0fb0xx14ie39trti4wxv-8vxv8rssmk743ojnwacrr2e7c 192.168.99.100:2377 Docker node ls ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS 03g1y59jwfg7cf99w4lt0f662 worker2 Ready Active 9j68exjopxe7wfl6yuxml7a7j worker1 Ready Active dxn1zf6l61qsb1josjja83ngz * manager1 Ready Active Leader
- 15. Docker Swarm - Walid Ashraf DEPLOYING A SERVICE
- 16. Docker Swarm - Walid Ashraf What is a service A service is a container in swarm mode. Examples of services might include an HTTP server, a database, or any other type of executable program that you wish to run in a distributed environment. Things to be configured in a service The port where the swarm will make the service available outside the swarm An overlay network for the service to connect to other services in the swarm CPU and memory limits and reservations A rolling update policy The number of replicas of the image to run in the swarm
- 17. Docker Swarm - Walid Ashraf
- 18. Docker Swarm - Walid Ashraf Replicated and global services
- 19. Docker Swarm - Walid Ashraf Creating a service $docker service create --replicas 1 --name helloworld alpine ping docker.com $ docker service ls •ID NAME SCALE IMAGE COMMAND •9uk4639qpg7n helloworld 1/1 alpine ping docker.com $ docker service inspect --pretty helloworld •ID: 9uk4639qpg7npwf3fn2aasksr •Name: helloworld •Mode: REPLICATED •Replicas: 1 •Placement: •UpdateConfig: •Parallelism: 1 •ContainerSpec: •Image: alpine •Args: ping docker.com $ docker service ps helloworld •ID NAME SERVICE IMAGE LAST STATE DESIRED STATE NODE •8p1vev3fq5zm0mi8g0as41w35 helloworld.1 helloworld alpine Running 3 minutes Running worker2
- 20. Docker Swarm - Walid Ashraf Scaling a service $ docker service scale helloworld=5 $ docker service ps helloworld ID NAME SERVICE IMAGE LAST STATE DESIRED STATE NODE 8p1vev3fq5zm0mi8g0as41w35 helloworld.1 helloworld alpine Running 7 minutes Running worker2 c7a7tcdq5s0uk3qr88mf8xco6 helloworld.2 helloworld alpine Running 24 seconds Running worker1 6crl09vdcalvtfehfh69ogfb1 helloworld.3 helloworld alpine Running 24 seconds Running worker1 auky6trawmdlcne8ad8phb0f1 helloworld.4 helloworld alpine Running 24 seconds Accepted manager1 ba19kca06l18zujfwxyc5lkyn helloworld.5 helloworld alpine Running 24 seconds Running worker2
- 21. Docker Swarm - Walid Ashraf Delete a service $ docker service rm helloworld helloworld
- 23. Docker Swarm - Walid Ashraf Thinking about High Availability
- 24. Docker Swarm - Walid Ashraf HA over Multiple clouds
- 25. Docker Swarm - Walid Ashraf Implementing High Availability Note: Default Discovery service needs a key value configuration manager Manager1 swarm manage -H :4000 <tls-config-flags> --replication --advertise 192.168.42.200:4000 consul://192.168.42.10:8500/nodes Manager 2 swarm manage -H :4000 <tls-config-flags> --replication --advertise 192.168.42.201:4000 consul://192.168.42.10:8500/nodes
- 26. Docker Swarm - Walid Ashraf TLS for Docker Swarm
- 27. Docker Swarm - Walid Ashraf References https://docs.docker.com/swarm/ https://docs.docker.com/engine/swarm/swarm-tutorial
- 28. Docker Swarm - Walid Ashraf
Editor's Notes
- #27: https://docs.docker.com/swarm/configure-tls/