Deploying and Scaling a Rails Application with Docker and Friends
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The document details the deployment and scaling of a Rails application using Docker, Consul, and related tools. It outlines the steps for building and running a multi-container application with Docker Compose, scaling services with Docker Swarm, and utilizing Consul for service discovery and health checking. Additionally, it discusses automating service registration and configuration updates using Registrator and Consul Template for dynamic environments.
![Consul - Service Discovery
Register service with consul
$ curl -X PUT
-d "{"ID": "app001", "Name": "app", "Tags": [], "Port": 5000}"
0.0.0.0:8500/v1/agent/services/register
List of services can now be queried via API
$ curl 0.0.0.0:8500/v1/catalog/services
{"app": [], "consul": []}](https://image.slidesharecdn.com/docker-swarm-consul-150317033622-conversion-gate01/85/Deploying-and-Scaling-a-Rails-Application-with-Docker-and-Friends-26-320.jpg)
![Consul - Service Discovery
A single service definition via API
$ curl 0.0.0.0:8500/v1/catalog/service/app
[
{
"ServicePort": 49153,
"ServiceAddress": "",
"ServiceTags": null,
"ServiceName": "app",
"ServiceID": "swarm-0:dockeransible_app_1:5000",
"Address": "10.129.127.240",
"Node": "swarm-0"
}
]](https://image.slidesharecdn.com/docker-swarm-consul-150317033622-conversion-gate01/85/Deploying-and-Scaling-a-Rails-Application-with-Docker-and-Friends-27-320.jpg)
Deploying and Scaling a Rails Application with Docker and Friends
- 1. Deploying and Scaling a Rails Application with Docker, Consul and Friends
- 6. A Dockerfile for Rails FROM invisiblelines/ruby:2.2.0 MAINTAINER Kieran Johnson "kieran@invisiblelines.com" ENV PORT 5000 RUN curl -sL https://deb.nodesource.com/setup | sudo bash - && apt-get -qqy install nodejs -y; apt-get clean -y; apt-get autoremove -y RUN apt-get -qq update; apt-get -qqy install libpq-dev; apt-get clean -y; apt-get autoremove -y
- 7. Build and Run Build $ docker build -t myapp . Run $ docker run -d -p 5000:5000 myapp
- 8. A Simple Rails Stack 3 containers on one node App Postgres Nginx
- 9. Setup the Containers Start a database container $ docker run -d --name db postgres:9.4.0
- 10. Setup the Containers Run our app and link it to the database container $ docker run -d --name myapp --link db:db -e DB_ENV_POSTGRES_USER=postgres -e DB_ENV_POSTGRES_PASSWORD=postgres myapp
- 11. Setup the Containers Add Nginx $ docker run -d -p 80:80 --name nginx --link myapp:myapp -v /Users/kieran/Desktop/docker-fig-rails-example/nginx.conf:/etc/nginx/conf.d/default.conf nginx
- 13. How To Scale?
- 15. A Dynamic and Scalable Docker Cluster
- 18. Docker Compose Sample dockercompose.yml postgres: image: postgres:9.4.0 environment: POSTGRES_USER: 'docker' POSTGRES_PASSWORD: 'mysupersecretpassword' app: build: . ports: - "5000:5000" links: - db environment: RACK_ENV: production DATABASE_URL: postgres://docker:mysupersecretpassword@postgres/docker
- 19. Docker Compose Start Application Stack $ docker-compose up -d Scale a Service $ docker-compose scale app=6
- 22. Docker Swarm Each node runs a Swarm agent pointing to a discovery service $ docker run -d swarm join --addr={{node_ip}}:2375 consul://consul.service.consul:8500/swarm Start a single Swarm manager with the same discovery service $ docker run -d -p {{swarm_port}}:2375 swarm manage consul://consul.service.consul:8500/swarm
- 23. Docker Swarm Interactions with Swarm are done through a the Swarm manager $ docker -H tcp://{{swarm_ip}}:{{swarm_port}} info ...
- 26. Consul - Service Discovery Register service with consul $ curl -X PUT -d "{"ID": "app001", "Name": "app", "Tags": [], "Port": 5000}" 0.0.0.0:8500/v1/agent/services/register List of services can now be queried via API $ curl 0.0.0.0:8500/v1/catalog/services {"app": [], "consul": []}
- 27. Consul - Service Discovery A single service definition via API $ curl 0.0.0.0:8500/v1/catalog/service/app [ { "ServicePort": 49153, "ServiceAddress": "", "ServiceTags": null, "ServiceName": "app", "ServiceID": "swarm-0:dockeransible_app_1:5000", "Address": "10.129.127.240", "Node": "swarm-0" } ]
- 28. Consul - DNS Service can now be also queried by DNS* $ dig A app.service.consul ; <<>> DiG 9.8.3-P1 <<>> A app.service.consul ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 55035 ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;app.service.consul. IN A ;; ANSWER SECTION: app.service.consul. 300 IN A 192.168.0.12 *Consul DNS runs on a nonstandard port so install DNSmasq to query this by default.
- 29. Consul - Health Checks Health checks monitor service Remove a service from DNS queries if it fails a health check
- 30. Consul - Key/Value Store Store application configuration data in the cluster Store a value $ curl -X PUT -d "bar" 0.0.0.0:8500/v1/kv/foo Retrieve a value $ curl 0.0.0.0:8500/v1/kv/foo?raw
- 32. Consul - Watches Using a watch we can perform a deployment across the cluster $ consul watch -type key -key app/sha /usr/local/bin/deploy.sh On Swarm Manager node add a watch for the key When this changes run a script In the script loop over the app containers stopping them one by one and starting the new container
- 37. Consul Template Update templates with values from Consul when any variable in the template changes Optionally run a command when the template has been generated $ consul-template -consul 0.0.0.0:8500 -template "/tmp/template.ctmpl:/var/www/nginx.conf:docker exec nginx /usr/sbin/nginx -s reload"
- 38. Consul Template Templates use Go templates {{range service "webapp@datacenter"}} server {{.Address}}:{{.Port}}{{end}}
- 40. Demo
- 42. The End