Container Cluster

Consul & SwarmEueung Mulyana

http://eueung.github.io/docker-stuff/consulCodeLabs | Attribution-ShareAlike CC BY-SA

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Outline

Consul - Introduction

RPI Swarm Cluster + Consul

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Consul

Introduction

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ConsulConsul is s a tool for discovering and con�guring services in

our infrastructure.

Key FeaturesService Discovery | Health Checking | Key/Value Store |

Multi Datacenter

Service DiscoveryClients of Consul can provide a service, such as api or mysql,

and other clients can use Consul to discover providers of agiven service. Using either DNS or HTTP, applications can

easily �nd the services they depend upon.

Health CheckingConsul clients can provide any number of health checks,either associated with a given service ("is the webserverreturning 200 OK"), or with the local node ("is memory

utilization below 90%"). This information can be used by anoperator to monitor cluster health, and it is used by theservice discovery components to route tra�c away from

unhealthy hosts.

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Key/Value StoreApplications can make use of Consul's hierarchical key/valuestore for any number of purposes, including dynamiccon�guration, feature �agging, coordination, leader election,and more. The simple HTTP API makes it easy to use.

Multi DatacenterConsul supports multiple datacenters out of the box. This meansusers of Consul do not have to worry about building additionallayers of abstraction to grow to multiple regions.

Ref: Introduction - Consul by HashiCorp

 

 

ArchitectureConsul is a distributed, highly available

system.

Every node that provides services to Consulruns a Consul agent. Running an agent is

not required for discovering other servicesor getting/setting key/value data. The agent

is responsible for health checking theservices on the node as well as the node

itself.

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The agents talk to one or more Consul servers. The Consulservers are where data is stored and replicated. The serversthemselves elect a leader. While Consul can function with oneserver, 3 to 5 is recommended to avoid failure scenarios leadingto data loss. A cluster of Consul servers is recommended foreach datacenter.

Components of your infrastructure that need to discover otherservices or nodes can query any of the Consul servers or any ofthe Consul agents. The agents forward queries to the serversautomatically.

Each datacenter runs a cluster of Consul servers. When a cross-datacenter service discovery or con�guration request is made,the local Consul servers forward the request to the remotedatacenter and return the result.

Ref: Introduction - Consul by HashiCorp

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RPI Swarm Cluster + Consul

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Let's rebuild our previous container clusterwith Consul..

Check it again if necessary: Docker Swarm Cluster

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A 3-Node RPIClusternode1192.168.1.102

node2192.168.1.101

node3192.168.1.100

$ ssh-keygen -R node1.local$ ssh-copy-id -oStrictHostKeyChecking=no -oCheckHostIP=no root@$node1.local

# if necessary$ ssh -oStrictHostKeyChecking=no -oCheckHostIP=no root@$node1.local$ ssh-keygen -R 192.168.1.102

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A Note

SSH Setting

# etc/default/dockerDOCKER_OPTS="--storage-driver=overlay -D -H tcp://0.0.0.0:2375 --cluster-store consul://192.168.1.102:8500 --cluster-advertise=eth0:2375"

# if necessary$ systemctl restart docker$ docker info $ ps aux | grep docker

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Engine Config

DOCKER_OPTS

$ ./start.sh node1.local

# start.sh

function getip() { (traceroute $1 2>&1 | head -n 1 | cut -d\( -f 2 | cut

IP_ADDRESS=$(getip $1)echo $IP_ADDRESS

docker -H $IP_ADDRESS:2375 run \ -d --net=host --name=consul \ -v /data -p 8500:8500 \ hypriot/rpi-consul:0.6.4 agent -server -data-dir /data -bootstrap-expect -ui-dir=/ui \ -advertise=$IP_ADDRESS -bind=$IP_ADDRESS -client=$IP_ADDRESS

docker -H $IP_ADDRESS:2375 run \ -d -p 10000:6000 --name=swarm-master \ hypriot/rpi-swarm:1.2.1 manage -H 0.0.0.0:6000 \ --discovery-opt="kv.path=docker/nodes" \ consul://$IP_ADDRESS:8500

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Start Consul &Swarm Master

$ export DOCKER_HOST=tcp://192.168.1.102:10000$ docker run -d -p 8080:80 hypriot/rpi-nano-httpd571d31928b3db90fc6baffa088c25c645f8d55d5e144dc03816ef5f6af62ae21

$ docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES571d31928b3d hypriot/rpi-nano-httpd "/httpd 80" 8d897b5aeab29 hypriot/rpi-swarm:1.2.1 "/swarm manage -H 0.0" dc1bb0bd5188 hypriot/rpi-consul:0.6.4 "/consul agent -serve"

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Check & Test

$ docker info

Containers: 3 Running: 3 - Paused: 0 - Stopped: 0Images: 11Server Version: swarm/1.2.1Role: primaryStrategy: spreadFilters: health, port, containerslots, dependency, affinity, constraintNodes: 3 node1: 192.168.1.102:2375 - ID: ASSH:N743:XQ4D:2B3A:LQA6:ESIO:PHBI:RPN7:NWMP:5WK2:4X4F:WNY5 - Status: Healthy - Containers: 2 - Reserved CPUs: 0 / 4 - Reserved Memory: 0 B / 971.8 MiB - Labels: executiondriver=native-0.2, kernelversion=4.1.17-hypriotos-v7+, operatingsystem=Raspbian GNU/Linux - Error: (none) - UpdatedAt: 2016-05-15T08:34:02Z - ServerVersion: 1.10.2 node2: 192.168.1.101:2375 - Containers: 1 - Reserved CPUs: 0 / 4 - Reserved Memory: 0 B / 971.8 MiB node3: 192.168.1.100:2375 - Containers: 0 - Reserved CPUs: 0 / 4 - Reserved Memory: 0 B / 971.8 MiB...Kernel Version: 4.1.17-hypriotos-v7+ - Operating System: linux - Architecture: armCPUs: 12Total Memory: 2.847 GiBName: d897b5aeab29

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Check & Test

Consul UI 

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Consul UI 

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Consul UI 

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$ docker run -d -p 9000:9000 hypriot/rpi-dockerui:v0.9.0 -e http://192.168a08588d3e7888952875e9f14496ccf5e943af954a8e70a4c51439025ff31a943

$ docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMESa08588d3e788 hypriot/rpi-dockerui "/dockerui -e http://" 6571d31928b3d hypriot/rpi-nano-httpd "/httpd 80" About an hour ago Up About an hour d897b5aeab29 hypriot/rpi-swarm:1.2.1 "/swarm manage -H 0.0" About an hour ago Up About an hour dc1bb0bd5188 hypriot/rpi-consul:0.6.4 "/consul agent -serve" About an hour ago Up About an hour node1/consul

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Now: UI for Docker

Try DockerUI

DockerUI 

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DockerUI 

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DockerUI 

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DockerUI 

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Refs

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Refs1. Introduction - Consul by HashiCorp2. Consul Architecture - Consul by HashiCorp3. kevana/ui-for-docker: An uno�cial web interface for Docker, formerly known

as DockerUI4. consul @ docker hub5. progrium/consul @ docker hub6. gliderlabs/consul @ docker hub | consul-agent | consul-server

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ENDEueung Mulyana

http://eueung.github.io/docker-stuff/consulCodeLabs | Attribution-ShareAlike CC BY-SA

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