Ansible Playbook Examples

Examples

We’ve put together some basic playbook examples to help you get started. If you are new to Ansible development, feel free to test them out.

Hello World

A basic playbook that prints “Hello World”, just to make sure we’re communicating with the VM, and are able to run the playbook. When run as part of an App’s deployment in CloudShell, the message will be displayed in the sandbox diagram’s Output window.

For example, the site.yml file may look something like this:

---
- hosts: all
  tasks:
  - name: Print Hello World
    debug: msg="Hello World"

Parameters

A playbook that prints the parameter defined in an App template or API call (see below). Such playbooks are useful for debugging and making sure parameter variables are set with the correct values. Note that the parameters are stored as environment variables on the App instance in the sandbox.

The site.yml file will look something like this:

---
- hosts: all
  vars: 
  - msg: "{{P1|default('No Message')}}"
  tasks:
  - name: Print P1
    debug: var=msg
  • Parameter defined in the App template:

Discovery Dialog

  • Parameter defined in the ConfigureApps API method (python file):
Python
from cloudshell.api.cloudshell_api import *

session = CloudShellAPISession('localhost', 'admin', 'admin', 'Global')
session.ConfigureApps(
    reservationId='dfb2df41-334e-4630-8bc6-ec846eb072d6',
    appConfigurations=[AppConfiguration('LinuxVmApp_9cb2-72d6', [ConfigParam('P1', 'Hello World From Here!')])],
    printOutput=True
)

Note: Since this script uses parameters defined on the App template, it will not work when run manually outside of CloudShell. For this to work, you will need to edit the python code as follows:

  • Update the CloudShell settings passed to the session variable, if needed.
  • Specify the ID of an active sandbox (in the reservationId field of the python code).
  • Replace ‘LinuxVmApp_9cb2-72d6’ with the App’s name.

Inventory Groups

In some cases, a playbook contains plays that target many different VMs that require configuration. In order to have the playbook run only the plays that are relevant to a specific VM, or to a group of hosts (VMs) that your VM belongs to, you can use the Inventory Groups field in the App template. In this field, specify the groups that your VM belongs to (more than one group can be provided). Use semicolons “;” to separate multiple groups.

For example , specifying groups “servers/http” and servers/sql”:

Discovery Dialog

This example shows how these groups entered in the App’s Configuration Management page should be written in the Ansible hosts file.

hosts
[servers:children]
http
sql

[http]
192.168.1.2

[sql]
192.168.1.12

Privilege escalation

Now let’s say you want Ansible to dynamically get the user and password from the App when running a task on a particular App’s VM. This is useful if the VM credentials on the App are not strong enough for the task you wish to run. To achieve this, you will need to add the following two parameters to your App’s Configuration Management tab:

  • ansible_become_user - the user with the stronger permissions (probably a root user)
  • ansible_become_pass - the password to that user

For example:

Discovery Dialog

And modify the site.yml file to get the relevant VM’s user and password from these parameters for each task:

---
- hosts: all
  tasks:    
    - name: Get sudoers file content
      become: yes
      become_method: su
      command: cat /etc/sudoers
      register: cmd_var

    - name: Print output
      debug: msg= "{{ cmd_var.stdout }}"