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Infrastructure = Code
Georg M. Sorst
CTO, FINDOLOGIC GmbH
What’s the challenge?
Who has already setup 1 server?
2 servers?
10, 1.000, 10.000?
Danger zone
● Setup: Manual shell commands
● Testing: Manual
● Multiple admins: Overwrite each other’s fixes
● Updates: Different versions on every server
Develop like it’s 1999
● Software Development has solved these issues:
● Installation: Deployment Scripts
● Testing: Unit Tests
● Multiple developers: git merge
● Updates: Version tagging
Infrastructure = Code?
● Define the desired state of the servers
● In human readable form
● Commit to VCS
● Automatically run tests
● Setup / Update server with single command
● Fail, fix and deploy
Ansible!
---
- hosts: webservers
tasks:
- name: ensure apache is at the latest version
yum: name=httpd state=latest
- name: write the apache config file
template: src=/srv/httpd.j2 dest=/etc/httpd.conf
notify:
- restart apache
- name: ensure apache is running (and enable it at boot)
service: name=httpd state=started enabled=yes
handlers:
- name: restart apache
service: name=httpd state=restarted
What?
● “Ansible” = fictional instantaneous hyperspace communication system
● Michael DeHaan 2012 / Red Hat
● Python
● Declare desired state, not how to get there○ name=apache state=present○ Idempotent
● Agentless○ Just needs SSH access
● Plain YAML○ Can be versioned
Structure
● Inventory: Which hosts / hostgroups are available?
● Hosts: Which hosts to run on?
● Vars: Use in config files, tasks etc.
● Tasks: What to do?
● Handlers: Restart service on config change
Inventory
https://docs.ansible.com/ansible/intro_inventory.html#groups-of-groups-and-group-variables
Playbook
https://github.com/georgms/ansible-meetup/blob/master/apache.yml
Demo
git clone https://github.com/georgms/ansible-meetup.git
Demo: Ansible + Vagrant
● vagrant up
● vagrant provision○ Idempotent
● http://localhost:8080/
Demo: Ansible + Docker
● Docker image with SSH + Python
● docker build -t ansible-meetup .
● docker run -i -t -p 8080:80 ansible-meetup
Testing, 1 2, Testing
● Use Ansible test modules○ Get response from port○ Check log file contents
● Jenkins: vagrant up
● Travis CI ○ https://github.com/georgms/ansible-meetup/blob/master/.travis.yml
● Automatically build Docker image / Vagrant box
What else
● Ad-hoc tasks: Reboot multiple servers
● Roles: This is a Web-Server, DB-Server, SSH
● Templates: Replace value in config file
● Conditionals: Run only on Ubuntu
● Loops: Install packages, create users
● Vault: Encrypt passwords, private keys
Lessons learned
● Use .d files, eg. /etc/apache2/conf.d/
● Takes a while to have really robust playbooks○ Absolutely requires automated testing
● Don’t make local changes on servers○ Commit to repo, run tests, deploy (just like code)
● < cowsay > --------
\ ^__^
\ (oo)\_______
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||----w |
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Ecosystem
● Ansible Galaxy: More than 5.000 roles available
● Ansible Tower: Centralized control panel, $$$
● Works well with OpenStack (both Red Hat)
What are my options?
● Puppet (requires agent, Ruby DSL)
● Chef (requires agent, Ruby based configs)
● Salt (agentless,YAML config)
Meetup
● 11.05.
