Tuesday, February 5, 2019

Using Ansible Dynamic Inventory with Azure can save the day for you.




As a DevOps Engineer, I always love to make things simple and convenient by automating them. Automation can be done on many fronts like infrastructure, software, build and release etc.

Ansible is primarily a software configuration management tool which can also be used as an infrastructure provisioning tool.
One of the thing that I love about Ansible is its integration with different cloud providers. This integration makes things really loosely coupled, For ex:- we don't require to manage whole information of cloud in Ansible (Like we don't need instance metadata information for provisioning it).

Ansible Inventory

Ansible uses a term called inventory to refer to the set of systems or machines that our Ansible playbook or command work against. There are two ways to manage inventory:-
  • Static Inventory
  • Dynamic Inventory
By default, the static inventory is defined in /etc/ansible/hosts in which we provide information about the target system. In most of the cloud platform when the server gets reboot then it reassigns a new public address and again we have to update that in our static inventory, so this can't be the lasting option.
Luckily Ansible supports the concept of dynamic inventory in which we have some python scripts and a .ini file through which we can provision machines dynamically without knowing its public or private address. Ansible Dynamic Inventory is fed by using external python scripts and .ini files provided by Ansible for cloud infrastructure platforms like Amazon, Azure, DigitalOcean, Rackspace.

In this blog, we will talk about how to configure dynamic inventory on the Azure Cloud Platform.

Ansible Dynamic Inventory on Azure

The first thing that always required to run anything is software and its dependencies. So let's install the software and its dependencies first. First, we need the python modules of azure that we can install via pip.

$ pip install 'ansible[azure]'

After this, we need to download azure_rm.py


$ wget https://raw.githubusercontent.com/ansible/ansible/devel/contrib/inventory/azure_rm.py

Change the permission of file using chmod command.

$ chmod +x azure_rm.py

Then we have to log in to Azure account using azure-cli

$ az login
To sign in, use a web browser to open the page https://aka.ms/devicelogin and enter the code XXXXXXXXX to authenticate.

The az login command output will provide you a unique code which you have to enter in the webpage i.e.
https://aka.ms/devicelogin

As part of the best practice, we should always create an Active Directory for different services or apps to restrict privileges. Once you logged in Azure account you can create an Active Directory app for Ansible

$ az ad app create --password ThisIsTheAppPassword --display-name opstree-ansible --homepage ansible.opstree.com --identifier-uris ansible.opstree.com

Don't forget to change your password ;). Note down the appID from the output of the above command.

Once the app is created, create a service principal to associate it with.

$ az ad sp create --id appID

Replace the appID with actual app id and copy the objectID from the output of the above command.
Now we just need the subscription id and tenant id, which we can get by a simple command

$ az account show

Note down the id and tenantID from the output of the above command.

Let's assign a contributor role to service principal which is created above.

$ az role assignment create --assignee objectID --role contributor

Replace the objectID with the actual object id output.

All the azure side setup is done. Now we have to make some changes to your system.

Let's start with creating an azure home directory

$ mkdir ~/.azure 

In that directory, we have to create a credentials file

$ vim ~/.azure/credentials

[default]
subscription_id=id
client_id=appID
secret=ThisIsTheAppPassword
tenant=tenantID

Please replace the id, appID, password and tenantID with the above-noted things.

All set !!!! Now we can test it by below command

$ python ./azure_rm.py --list | jq

and the output should be like this:-

{
  "azure": [
    "ansibleMaster"
  ],
  "westeurope": [
    "ansibleMaster"
  ],
  "ansibleMasterNSG": [
    "ansibleMaster"
  ],
  "ansiblelab": [
    "ansibleMaster"
  ],
  "_meta": {
    "hostvars": {
      "ansibleMaster": {
        "powerstate": "running",
        "resource_group": "ansiblelab",
        "tags": {},
        "image": {
          "sku": "7.3",
          "publisher": "OpSTree",
          "version": "latest",
          "offer": "CentOS"
        },
        "public_ip_alloc_method": "Dynamic",
        "os_disk": {
          "operating_system_type": "Linux",
          "name": "osdisk_vD2UtEJhpV"
        },
        "provisioning_state": "Succeeded",
        "public_ip": "52.174.19.210",
        "public_ip_name": "masterPip",
        "private_ip": "192.168.1.4",
        "computer_name": "ansibleMaster",
        ...
      }
    }
  }
}

Now you are ready to use Ansible in Azure with dynamic inventory. Good Luck :-)

3 comments:

  1. All are saying the same thing repeatedly, but in your blog I had a chance to get some useful and unique information, I love your writing style very much, I would like to suggest your blog in my dude circle, so keep on updates.

    DevOps Training in Pune

    DevOps Online Training

    ReplyDelete
  2. Thank you for the information, i found the information very useful. If anyone looking for Microsoft Azure training in Bangalore i suggest Apponix Technologies, they provide best Microsoft Azure training. For more information visit : https://www.apponix.com/Microsoft-Azure/Microsoft-Azure-Training-in-Bangalore.html

    ReplyDelete
  3. Thank you for your valuable content , Easy to understand and follow. As said, the migration to cloud is very essential for the protection of the database.

    Cloud Migration services
    Aws Cloud Migration services
    Azure Cloud Migration services
    Vmware Cloud Migration services
    Database Migration services
    Lia Infraservices

    ReplyDelete

What Without Internet

What without Internet? I had a dream a few days ago in which the existence of the internet was gone, When I woke up I though...