View source for Ansible/Vagrant

{{Main|Ansible}}

[[Vagrant]] is a command line interface to VirtualBox that allows you to create virtual machines from the command line and manage them. This is a convenient way of testing Ansible scripts locally without using the AWS or Google Cloud platforms.

Ansible can wrap around Vagrant and use it to automate the management of remote machines. This is useful for testing Ansible locally if you need to test it with multiple machines or particular architectures.

Details of how to connect to vagrant boxes can be added to the Ansible hosts file (see [[Ansible/Vagrant/Static Inventory]] for an example static inventory (hosts) file), or machines can be managed using a dynamic inventory script (see [[Ansible/Vagrant/Dynamic Inventory]] for an example Vagrant dynamic inventory script). This will allow Ansible to connect to the remote machines and execute commands.

==Before you begin: set up vagrant box==

See the [https://charlesreid1.com/wiki/Vagrant#Basic_Startup_Shutdown_Procedure Basic Startup and Shutdown Procedure] section of the [[Vagrant]] page for steps to set up a Vagrant box, and connect to it via SSH.

Briefly:

To clear everything out and destroy all old vagrant boxes:

<pre>
vagrant destroy --force
</pre>

To initialize a vagrant box:

<pre>
vagrant init ubuntu/xenial64
</pre>

To bring it up:

<pre>
vagrant up
</pre>

For info about the ssh configuration of the box:

<pre>
vagrant ssh-config
</pre>

To ssh into the box:

<pre>
vagrant ssh
</pre>

To halt the machine:

<pre>
vagrant halt
</pre>

Note: for multiple vagrant boxes, see the guide on the [https://charlesreid1.com/wiki/Ansible/Full_Stack_Playbook#Vagrant_multi-machine_setup Ansible/Full Stack Playbook] page.

==Connect Ansible to Vagrant==

Use the hosts file to tell Ansible how to connect to the (Vagrant) hosts.

===Managing hosts file by hand===

See [[Ansible/Vagrant/Static Inventory]]

===Managing hosts dynamically===

{{Main|Ansible/Vagrant/Dynamic Inventory}}

A dynamic inventory executable file can be used by specifying the path to the executable dynamic inventory script using the -i flag when running ansible:

<pre>
ansible -i dynamic_vagrant.py ...
</pre>

==Ping Vagrant box==

To ping the Vagrant machine (that Ansible is managing), use Ansible's ping module.

Call Ansible and the name of the machine (must be listed in the hosts file).

Pass it the inventory file name with the -i flag, and the ping module with the -m flag:

<pre>
ansible myvagrantbox -i hosts -m ping
</pre>

or if you're using a dynamic inventory file,

<pre>
ansible myvagrantbox -i hosts -m ping
</pre>

You should see some output like this:

<pre>
myvagrantbox | success >> {
    "changed": false,
    "ping": "pong"
}
</pre>

If it did not succeed, re-run with the <code>-vvvv</code> flag for max verbosity to help debug the issue.

This is a basic module that runs a ping test; the server should respond with a pong on the other end. 

The "'changed': false" indicates that Ansible is not changing the state of the machine.


==Use a config file==

The inventory file (hosts) required lots of details, and if we have many nodes to deal with that is not going to scale well.

To make it easier to deal with, we can use the <code>ansible.cfg</code> file to set some defaults and variables.

Where to put ansible.cfg? Here is where Ansible looks:

* <code>ANSIBLE_CONFIG</code> env var (specifies the config file)
* <code>/ansible.cfg</code> (current directory)
* <code>~/.ansible.cfg</code> (.ansible.cfg in your home directory
* <code>/etc/ansible/ansible.cfg</code>

A good place for it is alongside the playbooks, in the current directory. 

This dir structure allows you to place the config file, plus the playbooks, under version control in a single repo.

==Example config file==

To specify default values for SSH key, username, and inventory filename, use this config file:

'''<code>ansible.cfg</code>:'''

<pre>
[defaults]
inventory = hosts
remote_user = vagrant
private_key_file = .vagrant/machines/default/virtualbox/private_key
host_key_checking = False
</pre>

Now we can also simplify the hosts file:

'''<code>playbooks/hosts</code>:'''

<pre>
myvagrantbox ansible_host=127.0.0.1 ansible_port=2222
</pre>

Because the hosts file is already specified as the inventory file, we don't have to use the -i flag:

<pre>
$ ansible myvagrantbox -m ping
</pre>

==Executing arbitrary commands==

We have already seen the <code>-m</code> flag used with ansible to specify an ansible module. 

We can use the <code>command</code> module to run arbitrary commands on the vagrant machines that ansible is managing.

To run a command on the remote machine via ansible:

<pre>
ansible myvagrantbox -m command -a <the command to run>
</pre>

For example, to run the uptime command:

<pre>
ansible myvagrantbox -m command -a uptime
</pre>

Results in:

<pre>
testserver | success | rc=0 >>
 17:14:07 up  1:16,  1 user,  load average: 0.16, 0.05, 0.04
</pre>

===Important Note===

The command module '''is actually the default module'''!!! So we don't need to specify <code>-m command</code>, that is the default value:

<pre>
ansible myvagrantbox -a <the command to run>
</pre>

For example:

<pre>
ansible myvagrantbox -a uptime
</pre>

If the command has spaces in it, use quotes:

<pre>
ansible myvagrantbox -a "tail /var/log/dmesg"
</pre>

==Executing root commands==

To run commands that require root access, pass the <code>-b</code> flag to BECOME the root user:

<pre>
$ ansible myvagrantbox -b -a "tail /var/log/syslog"
</pre>

==Installing packages==

The apt module is useful for installing packages. Here's how you would install nginx:

<pre>
ansible myvagrantbox -b -m apt -a name=nginx
</pre>

'''IMPORTANT:''' The first apt module command you give should also run the equivalent of <code>apt-get update</code> before the package is installed. To do that, change the name to <code>name="nginx update_cache=yes"</code>:

<pre>
ansible myvagrantbox -b -m apt -a name="nginx update_cache=yes"
</pre>

==Starting services==

Once nginx is installed, the service can be started using the service module:

<pre>
ansible myvagrantbox -b -m service -a "name=nginx state=restarted"
</pre>

equivalent of running <code>sudo service nginx restart</code>