Deployment with capistrano

Revealing Hour CreationsSagar P Junnarkarsj@revealinghour.in@sagarjunnarkar

Deployment with capistrano

How do we deploy?

FTP,SFTP,SCP?SSH+GIT?Debian packages?Don’t know? Other team does it for you.

What are the issues●Lot of manual processes-backup db, update code, update db etc.●Room for error. steps could be missed.●Small organisation : loose server access and

permissions●Large organisation : too restrictive

permissions. locked down server env

What do we need?

What do we need?

●Give limited power to developers●Automate entire deployment process

System admins don’t want you to touching their stuff

System admins don’t want you to touching their stuff

Standard server env:●Convention●Consistency●Security●Monitoring

working together to get the job done

working together to get the job done

●Developers are able to deploy rapidly●Sys admins have tight control of environments●All manual process are automated

Capistrano www.capistranorb.com

●Introduced around 2006 by Jamis Buck of 37 signals●Written in ruby, initially for rails project●It is a developer tool for deploying web

applications. It is typically installed on your workstation and used to deploy your SCM to one or more servers.

Simplest explanation

●Lets you write scripts that say “ssh ontoremote machine and do things.”●Program your deployment actions

Setup and configuration

gem install capistranocap -T # List all commandscapify . #capistrano v2cap install #capistrano v3

Local Directory Structure

├── Capfile├── config│ ├── deploy│ │ ├── production.rb│ │ └── staging.rb│ └── deploy.rb└── lib └── capistrano

└── tasks

├── Capfile├── config

│ ├── deploy.rb

Server Directory Structure

myapp/releasesmyapp/current -> releases/20141001001122myapp/shared

Symlink for shared files

Symlinks are made back to the shared folder,so they are not lost between deployments.

e.g. myapp/current/uploads -> myapp/shared/uploads

How does it works

●No software installed on server, just locally●Capistrano builds commands to be executed

remotely●executed on the server over ssh

Local Server

Lookup current revision in source control

ssh into server using ssh public key

checkout specified revision from source control

copy a new timestamped site directory

Add symlinks to shared directories

update current symlink to new site directory

Simple Deployment Workflow

Hooks

Before and after hooks at each stage of the deployment lifecycleExtend or customise default capistrano behaviorExamples: deploy, deploy:setup,deploy:symlink, deploy:update_code, deploy:rollback

Some common recipes

cap deploy # Deploys your project.cap deploy:check # Check required files and directories existcap deploy:cleanup # Clean up old releases.cap deploy:migrate # Run the migrate rake task.

Deploy configurationIn deploy.rbset :application, ‘site.com’’set :scm, :gitset :repository, “git@github.com/sagarjunnarkar/site.git”set :branch, “master”set :port, 22set :user, 'ubuntu'set :deploy_to, “/home/#{user}/#{application}” #/home/ubuntu/site.comrole :app, ‘www.example.com’#server "54.169.95.188", :web

Made mistake

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Rollback deployment

cap deploy:rollbackSet current symlink to previous release directory

Questions

Thank you