/puppet-to-ansible

Slides about Puppet to Ansible migration

From Puppet to Ansible

Who am I?

  • Currently Platform Engineering Manager @ ContentSquare
  • Widely adopted and used Puppet in several companies
  • Got troubles
  • Then decided to move to Ansible
  • Lots of benefits
  • But still got troubles :-)

puppet-logo

Scope: systems configuration,

applications deployment

Puppet issues (1/2)

  • Duplicated code in some modules
  • Not-fully functionnal modules (UNIX users...)
  • Implement services discovery?
  • CI integration (Jenkins)
  • Infrastructure resources management:
    • EC2: instances, ELB, security groups
    • Network: VPC, subnets, firewall rules
    • Route 53: domain names

Puppet issues (2/2)

  • Enterprise ecosystem
  • Mix of Puppet-DSL and Ruby
  • Complex production setup (master, CA, agents...) Puppetization of PuppetMaster?
  • Random ordering (soup of require)
  • Need a custom external node

ansible

Scope: Infrastructure provisionning, systems

configuration, applications deployment

Ansible

Decision to move away from Puppet was driven by:

  • CI tools integration (Jenkins) (thanks to Push, not Pull, paradigm)
  • Properly manage infrastructure resources (servers, load balancers, domain names, firewall rules...)
  • Overall team's motivation

Examples

Time to show real-life code!

(or almost real-life)

Example 1: File (Puppet)

file {$myscript:
  content => template('path/to/mytemplate.erb')
  owner   => $app_user,
  group   => $app_group,
  mode    => '0755',
  require => Archive['hbase'],
}

Template :

<% myvar.each do |key, value| -%>
    <%= key %>=<%= value %>
<% end %>

Example 1: File (Ansible)

- name: "Update config file in {{ app_dir }}"
  become: yes
  template:
    src: myfile.j2
    dest: "{{ app_dir }}/application.conf"
    owner: "{{ app_user }}"
    group: "{{ app_group }}"
    state: present
  tags:
    - app
{% for key, value in myvar.iteritems() %}
	{{ key }}={{ value }}
{% endfor %}

Example 2: Loop (Puppet)

(Old-style syntax)

define puppet::binary::symlink ($pkg = $title) {
  file {"/usr/bin/${pkg}":
    ensure => link,
    target => "/opt/puppetlabs/bin/${pkg}",
  }
}

$pkgs = ['facter', 'hiera', 'mco', 'puppet', 'puppetserver']

puppet::binary::symlink { $pkgs: }

Example 2: Loop (Ansible)

- name: "Installing useful set of packages"
  apt:
    name: "{{ item }}"
    state: present
  become: yes
  with_items:
    - htop
    - curl
    - jnettop

Example 3: Vars management (Ansible)

- name: "List old releases"
  become: yes
  shell: "ls -t {{ app_user.home }}/ | tail -n +5"
  changed_when: False
  register: ls_output

- name: "Remove oldest releases"
  become: yes
  file:
    name: "{{ app_user.home }}/{{ item }}"
    state: absent
  with_items:
    - ls_output.stdout_lines

Conclusion

Ansible concerns

Not a paradise-island...

  • Variables factorization: Vars? Default? Group vars? Extra vars?
  • Variables scope & precedence
  • Fast development cycles

Benefits

  • No issues with repeated instructions
  • Clear dependencies management (meta/)
  • Easy guidelines-checking
  • Tags management
  • Ansible Vault

Current state

  • Management of all AWS resources
  • Jenkins integration
  • Set of blocking guidelines
  • Dynamic inventory for ES/Kafka IPs
  • Automatic CIDR for subnets definitions (Jinja filter)

Next steps

  • Advanced tags management
  • Playbooks tests