Introction to docker swarm
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This document introduces Docker Swarm for clustering Docker hosts into a single virtual host. It discusses using Swarm with Consul and an overlay network. Key points: - Docker Swarm turns a pool of Docker hosts into a single virtual host with a standard API. - Consul provides service discovery, key-value storage, and health checking. - An overlay network allows containers on different hosts to communicate, with networking defined by Docker but implemented by the hosts' kernels.
Introction to docker swarm
- 1. Introduction to Docker Swarm Hsi-Kai Wang
- 2. Outline • Docker Cluster • Swarm • Swarm + Consul + overlay network
- 3. What is PC Cluster • A computer cluster consists of a set of loosely or tightly connected computers that work together so that, in many respects, they can be viewed as a single system. Unlike grid computers, computer clusters have each node set to perform the same task, controlled and scheduled by software. Ref: Computer cluster wiki
- 4. Docker Cluster Software • Apchae Mesos – abstract resource • docker swarm – easy way to cluster – standard Docker API • kubernetes – container merge – sample scaling
- 5. What is Swarm • Docker Swarm is native clustering for Docker. It turns a pool of Docker hosts into a single, virtual Docker host. Because 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. Software Environment • OS – CentOS: 7 (7.1.1503) • Software – Docker 1.10 (1.10.3.cs2) – Docker container network (Docker >= 1.9) – Swarm (Docker >= 1.5, 2375 port) – Consul
- 7. Swarm cluster Docker Host 172.17.33.83 Docker Host 172.17.33.84 Docker Host swarmswarmswarm Docker Host swarm 172.17.33.86 swarm cluster swarm manager swarm node
- 8. Docker - Setting• # docker install (Commercially Support, CS) centos:~ # rpm --import https://sks- keyservers.net/pks/lookup?op=get&search=0xee6d536cf7dc86e2d7d5 6f59a178ac6c6238f52e centos:~ # yum install yum-utils centos:~ # yum-config-manager --add-repo https://packages.docker.com/1.10/yum/repo/main/centos/7 centos:~ # yum install docker-engine centos:~ # systemctl enable docker.service centos:~ # systemctl start docker.service centos:~ # docker version # check version >= 1.5 • # docker config centos:~ # vi /etc/systemd/system/multi- user.target.wants/docker.serivce ... ExecStart=/usr/bin/docker daemon -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock ... centos:~ # systemctl restart docker.service centos:~ # docker pull swarm update setting
- 9. Swarm - config • # run once to get swarm token_id centos:~ # docker run --rm swarm create c4602d1cf638ac9805a0693499f04404 • # setup swarm node node:~ # docker run -d swarm join -- advertise=172.17.33.83:2375 token://c4602d1cf638ac9805a0693499f04404 • # setup swarm manager manager:~ # docker run -d -p 2375:2375 swarm manage token://c4602d1cf638ac9805a0693499f04404 • # list swarm cluster manager/node:~ # docker run --rm swarm list token://c4602d1cf638ac9805a0693499f04404 swarm node IP token id
- 10. Swarm - usage • # usage 1 manager:~ # docker -H 172.17.33.86:2375 info manager:~ # docker -H 172.17.33.86:2375 run hello-world manager:~ # docker -H 172.17.33.86:2375 ps -a • # usage 2 manager:~ # export DOCKER_HOST=172.17.33.86:2375 manager:~ # docker info manager:~ # docker run hello-world manager:~ # unset DOCKER_HOST swarm manager IP swarm manager IP
- 11. Key/Value Server for Docker • Apache ZooKeeper • Consul • etcd
- 12. What is Consul • Consul has multiple components, but as a whole, it is a tool for discovering and configuring services in your infrastructure. It provides several key features: – Service Discovery – Key/Value Store – Multi Datacenter – Health Checking
- 13. Docker container network • Default Networks – bridge – none – host • User-Defined Networks – bridge – overlay
- 14. Default Networks Container eth0 Host eth0 docker0 vethxx Container eth0 Container eth0 bridge network none network host network
- 16. Swarm cluster + Consul + overlay network Docker Host 172.17.33.83 Docker Host 172.17.33.84 Docker Host swarmswarmswarm Docker Host swarm 172.17.33.86 swarm cluster swarm manager swarm node consul
- 17. Consul • # consul install consul:~ # docker pull progrium/consul consul:~ # docker run -d -p 8500:8500 progrium/consul -server - bootstrap • # consul test consul:~ # curl -L http://172.17.33.86:8500/v1/catalog/nodes consul IP
- 18. Docker - Setting • # docker install (Commercially Support, CS) centos:~ # rpm --import https://sks- keyservers.net/pks/lookup?op=get&search=0xee6d536cf7dc86e2d7d5 6f59a178ac6c6238f52e centos:~ # yum install yum-utils centos:~ # yum-config-manager --add-repo https://packages.docker.com/1.10/yum/repo/main/centos/7 centos:~ # yum install docker-engine centos:~ # systemctl enable docker.service centos:~ # systemctl start docker.service centos:~ # docker version # check version >= 1.9 • # docker config centos:~ # vi /etc/systemd/system/multi- user.target.wants/docker.serivce ... ExecStart=/usr/bin/docker daemon -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock --cluster-store=consul://172.17.33.86:8500 --cluster- advertise=172.17.33.83:2375 ... centos:~ # systemctl restart docker.service centos:~ # docker pull swarm consul IP swarm node IP
- 19. Swarm • # setup swarm node node:~ # docker run -d swarm join --advertise=172.17.33.83:2375 consul://172.17.33.86:8500/dc1 • # setup swarm manager manager:~ # docker run -d -p 2376:2375 swarm manage consul://172.17.33.86:8500/dc1 • # list swarm cluster manager:~ # docker run --rm swarm list consul://172.17.33.86:8500/dc1 swarm node IPconsul IP
- 20. overlay network • manager:~ # docker network create -d overlay onetwork manager:~ # docker network ls • manager:~ # docker run -itd --name=abc -- env="constraint:node==d1" --net=onetwork ubuntu /bin/bash manager:~ # docker run -itd --name=xyz -- env="constraint:node==d2" --net=onetwork ubuntu /bin/bash manager:~ # docker ps --subnet=10.0.9.0/24 --ip-range=10.0.9.0/24
- 21. overlay network • manager:~ # docker network inspect onetwork manager:~ # docker exec -it abc ping -c3 10.0.0.3
- 22. Reference • Manually Install the CS Docker Engine • Understand Docker container networks • 深入瞭解 Docker Container Networks • 用Docker Swarm打造多主機叢集環境 • Docker cluster with swarm, consul, registrator and consul-template