vaguerent/website/docs/source/v2/provisioning/ansible_intro.html.md

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Ansible - Short Introduction	provisioning-ansible-intro

Ansible and Vagrant

The information below is applicable to both Ansible provisioners:

• ansible, where Ansible is executed on the Vagrant host

• ansible_local, where Ansible is executed on the Vagrant guest

The list of common options for these two provisioners is documented in a separate documentation page.

This documentation page will not go into how to use Ansible or how to write Ansible playbooks, since Ansible is a complete deployment and configuration management system that is beyond the scope of Vagrant documentation.

To learn more about Ansible, please consult the Ansible Documentation Site.

The Playbook File

The first component of a successful Ansible provisioner setup is the Ansible playbook which contains the steps that should be run on the guest. Ansible's playbook documentation goes into great detail on how to author playbooks, and there are a number of best practices that can be applied to use Ansible's powerful features effectively.

A playbook that installs and starts (or restarts) the NTP daemon via YUM looks like:

---
- hosts: all
  tasks:
    - name: ensure ntpd is at the latest version
      yum: pkg=ntp state=latest
      notify:
      - restart ntpd
  handlers:
    - name: restart ntpd
      service: name=ntpd state=restarted

You can of course target other operating systems that don't have YUM by changing the playbook tasks. Ansible ships with a number of modules that make running otherwise tedious tasks dead simple.

Running Ansible

The playbook option is strictly required by both Ansible provisioners (ansible and ansible_local), as illustrated in this basic Vagrantfile` configuration:

Vagrant.configure(2) do |config|

  # Use :ansible or :ansible_local to
  # select the provisioner of your choice
  config.vm.provision :ansible do |ansible|
    ansible.playbook = "playbook.yml"
  end
end

Since an Ansible playbook can include many files, you may also collect the related files in a directory structure like this:

.
|-- Vagrantfile
|-- provisioning
|   |-- group_vars
|           |-- all
|   |-- roles
|           |-- bar
|           |-- foo
|   |-- playbook.yml

In such an arrangement, the ansible.playbook path should be adjusted accordingly:

Vagrant.configure(2) do |config|
  config.vm.provision "ansible" do |ansible|
    ansible.playbook = "provisioning/playbook.yml"
  end
end

The Inventory File

When using Ansible, it needs to know on which machines a given playbook should run. It does this by way of an inventory file which lists those machines. In the context of Vagrant, there are two ways to approach working with inventory files.

Auto-Generated Inventory

The first and simplest option is to not provide one to Vagrant at all. Vagrant will generate an inventory file encompassing all of the virtual machines it manages, and use it for provisioning machines.

Example with the ansible provisioner:

# Generated by Vagrant

default ansible_ssh_host=127.0.0.1 ansible_ssh_port=2200 ansible_ssh_user='vagrant' ansible_ssh_private_key_file='/home/.../.vagrant/machines/default/virtualbox/private_key'

Note that the generated inventory file is stored as part of your local Vagrant environment in .vagrant/provisioners/ansible/inventory/vagrant_ansible_inventory.

Example with the ansible_local provisioner:

# Generated by Vagrant

default ansible_connection=local

Note that the generated inventory file is uploaded to the guest VM in a subdirectory of tmp_path, e.g. /tmp/vagrant-ansible/inventory/vagrant_ansible_local_inventory.

How to generate Inventory Groups:

The groups option can be used to pass a hash of group names and group members to be included in the generated inventory file.

With this configuration example:

Vagrant.configure(2) do |config|

  config.vm.box = "ubuntu/trusty64"

  config.vm.define "machine1"
  config.vm.define "machine2"

  config.vm.provision "ansible" do |ansible|
    ansible.playbook = "playbook.yml"
    ansible.groups = {
      "group1" => ["machine1"],
      "group2" => ["machine2"],
      "all_groups:children" => ["group1", "group2"]
    }
  end
end

Vagrant would generate an inventory file that might look like:

# Generated by Vagrant

machine1 ansible_ssh_host=127.0.0.1 ansible_ssh_port=2200 ansible_ssh_user='vagrant' ansible_ssh_private_key_file='/home/.../.vagrant/machines/machine1/virtualbox/private_key'
machine2 ansible_ssh_host=127.0.0.1 ansible_ssh_port=2222 ansible_ssh_user='vagrant' ansible_ssh_private_key_file='/home/.../.vagrant/machines/machine2/virtualbox/private_key'

[group1]
machine1

[group2]
machine2

[all_groups:children]
group1
group2

Notes:

• Prior to Vagrant 1.7.3, the ansible_ssh_private_key_file variable was not set in generated inventory, but passed as command line argument to ansible-playbook command.
• The generation of group variables blocks (e.g. [group1:vars]) are intentionally not supported, as it is not recommended to store group variables in the main inventory file. A good practice is to store these group (or host) variables in YAML files stored in group_vars/ or host_vars/ directories in the playbook (or inventory) directory.
• Unmanaged machines and undefined groups are not added to the inventory, to avoid useless Ansible errors (e.g. unreachable host or undefined child group)

For example, machine3, group3 and group1:vars in the example below would not be added to the generated inventory file:

ansible.groups = {
  "group1" => ["machine1"],
  "group2" => ["machine2", "machine3"],
  "all_groups:children" => ["group1", "group2", "group3"],
  "group1:vars" => { "variable1" => 9, "variable2" => "example" }
}

Static Inventory

The second option is for situations where you'd like to have more control over the inventory management.

With the inventory_path option, you can reference a specific inventory resource (e.g. a static inventory file, a dynamic inventory script or even multiple inventories stored in the same directory). Vagrant will then use this inventory information instead of generating it.

A very simple inventory file for use with Vagrant might look like:

default ansible_ssh_host=192.168.111.222

Where the above IP address is one set in your Vagrantfile:

config.vm.network :private_network, ip: "192.168.111.222"

Notes:

• The machine names in Vagrantfile and ansible.inventory_path files should correspond, unless you use ansible.limit option to reference the correct machines.
• The SSH host addresses (and ports) must obviously be specified twice, in Vagrantfile and ansible.inventory_path files.
• Sharing hostnames across Vagrant host and guests might be a good idea (e.g. with some Ansible configuration task, or with a plugin like vagrant-hostmanager).

The Ansible Configuration File

Certain settings in Ansible are (only) adjustable via a configuration file, and you might want to ship such a file in your Vagrant project.

When shipping an Ansible configuration file it is good to know that:

• it is possible to reference an Ansible configuration file via ANSIBLE_CONFIG environment variable, if you want to be flexible about the location of this file.

• ansible-playbook never looks for ansible.cfg in the directory that contains the main playbook file.

• As of Ansible 1.5, the lookup order is the following:

  • ANSIBLE_CONFIG an environment variable
  • ansible.cfg in the runtime current directory
  • .ansible.cfg in the user home directory
  • /etc/ansible/ansible.cfg