Anton Sukhachev
Articles Projects

Continuous delivery with Travis CI and Ansible

Setting up continuous delivery for your project with github.com

Requirements:

Setting Up the Server for Project Deployment 

[ root@2.2.2.2 ] adduser ansible # add a user under which Ansible will connect to the server and in whose directory the project will be deployed.
[ root@2.2.2.2 ] su - ansible
[ ansible@2.2.2.2 ] ssh-keygen -t rsa -b 4096 -C 'github' -f ~/.ssh/github_key # generate a key without a passphrase for deploying the repository.
[ ansible@2.2.2.2 ] eval "$(ssh-agent -s)"
[ ansible@2.2.2.2 ] ssh-add ~/.ssh/github_key
[ ansible@2.2.2.2 ] cat ~/.ssh/github_key.pub # display and copy the public key github_key.pub

Add the public key github_key.pub to the deploy keys for the repository on github.com
(In the repository settings on github.com, go to the "Deploy keys" tab)

Settings up Ansible server 

[ root@1.1.1.1 ] yum install ansible
[ root@1.1.1.1 ] adduser ansible # add a user under which Travis will access this server.
[ root@1.1.1.1 ] su - ansible
[ ansible@1.1.1.1 ] ssh-keygen -t rsa -b 4096 -C 'ansible' -f ~/.ssh/ansible_key # generate a key without a passphrase for connecting to the server with the project
[ ansible@1.1.1.1 ] eval "$(ssh-agent -s)"
[ ansible@1.1.1.1 ] ssh-add ~/.ssh/ansible_key
[ ansible@1.1.1.1 ] cat ~/.ssh/ansible_key.pub # display and copy the public key ansible_key.pub

Add the public key ansible_key.pub to the server of our project. 

[ ansible@2.2.2.2 ] mcedit .ssh/authorized_keys
[ ansible@2.2.2.2 ] chmod 600 .ssh/authorized_keys

Add the IP address of our project server to the hosts.yml file. 

[ ansible@1.1.1.1 ] mcedit /path/to/ansible/hosts.yml

hosts.yml 

[ansible]
2.2.2.2

Write a small playbook that will deploy the latest version of the master branch 

[ ansible@1.1.1.1 ] mcedit /path/to/ansible/playbook.yml

playbook.yml 

- hosts: all
   user: ansible
   tasks:
       - name: Clone git repo
         git:
             repo: ssh://git@github.com/{github_username}/{github_repo}.git
             dest: /home/ansible/var/www/{github_repo}
             version: master
             accept_hostkey: yes
             force: yes

Setting up Travis

Register on the site travis-ci.org using your github.com account. Enable integration for the desired repository.
In the Travis repository settings, enable:

On your local machine, where your project is deployed, install the travis utility and authenticate: 

[ user@local ] gem install travis
[ user@local ] travis login --auto

Generate a key without a passphrase to connect Travis to the server with Ansible. 

[ user@local ] ssh-keygen -t rsa -b 4096 -C 'travis' -f travis_key # generate a key without a passphrase to connect Travis to the server with Ansible
[ user@local ] cat travis_key.pub # display and copy the public key travis_key.pub

Add the public key travis_key.pub to the server Ansible in the file /home/ansible/.ssh/authorized_keys. 

[ ansible@1.1.1.1 ] mcedit /home/ansible/.ssh/authorized_keys
[ ansible@1.1.1.1 ] chmod 600 /home/ansible/.ssh/authorized_keys

Encrypt the private key using the travis utility: 

[ user@local ] travis encrypt-file travis_key --add

The output should be a file travis_key.enc and .travis.yml. The .travis.yml file will contain a line for decrypting our key like this: 

openssl aes-256-cbc -K $encrypted_412afa050e5f_key -iv $encrypted_412afa050e5f_iv -in travis_key.enc -out /tmp/travis_key -d

Add both files to git: 

[ user@local ] git add travis_key.enc .travis.yml

Edit the file .travis.yml: 

[ user@local ] mcedit /path/to/repo/.travis.yml

.travis.yml 

language: node_js # node_js project
install: true # do not install additional dependencies
sudo: false
branches: # the deployment of the project will only occur when there are changes in the master branch
  only:
      - master
script:
    - openssl aes-256-cbc -K $encrypted_412afa050e5f_key -iv $encrypted_412afa050e5f_iv -in travis_key.enc -out /tmp/travis_key -d #дешифруем ключ
    - eval "$(ssh-agent -s)"
    - chmod 600 /tmp/travis_key
    - ssh-add /tmp/travis_key
    - ssh -o "StrictHostKeyChecking no" ansible@1.1.1.1 'ansible-playbook playbook.yml' #подключаемся к серверу Ansible и запускаем playbook

Push the changes to git: 

[ user@local ] git push origin master

After this, a Build should appear on the repository page in Travis similar to the following: 

The command "openssl aes-256-cbc -K $encrypted_412afa050e5f_key -iv $encrypted_412afa050e5f_iv -in travis_key.enc -out /tmp/travis_key -d" exited with 0.

0.01s$ eval "$(ssh-agent -s)"
Agent pid 1842
The command "eval "$(ssh-agent -s)"" exited with 0.

0.01s$ chmod 600 /tmp/travis_key
The command "chmod 600 /tmp/travis_key" exited with 0.

0.01s$ ssh-add /tmp/travis_key
Identity added: /tmp/travis_key (/tmp/travis_key)
The command "ssh-add /tmp/travis_key" exited with 0.

16.68s$ ssh -o "StrictHostKeyChecking no" ansible@2.2.2.2 'ansible-playbook playbook.yml'
Warning: Permanently added '2.2.2.2' (ECDSA) to the list of known hosts.

PLAY [all] *********************************************************************
TASK [setup] *******************************************************************
ok: [2.2.2.2]
TASK [Clone git repo] **********************************************************
changed: [2.2.2.2]
PLAY RECAP *********************************************************************
2.2.2.2               : ok=1   changed=1    unreachable=0    failed=0   
The command "ssh -o "StrictHostKeyChecking no" ansible@2.2.2.2 'ansible-playbook playbook.yml" exited with 0.
Done. Your build exited with 0.

Now, whenever changes are made to the master branch, Travis will trigger Ansible, which will deploy the latest version of your code to the project server.

I hope this guide will be useful to someone.