Setup Prerequisites<\/h2>\n
To follow this setup, you should have the following.<\/p>\n
- \n
- One server for Ansible Control Node<\/li>\n
- One or more ansible hosts to test ansible remote configurations and ad-hoc commands.<\/li>\n<\/ol>\n
Install Ansible on Ubuntu<\/h2>\n
Choose the following methods for installing Ansible.<\/p>\n
1. Using Pip<\/h3>\n
If you have python-pip installed in your system, use the following pip command.<\/p>\n
sudo pip install ansible<\/p>\n
2. Using Ubuntu apt repository<\/h3>\n
To install it from the apt repository, execute the following commands to install ansible.<\/p>\n
sudo apt-add-repository -y ppa:ansible\/ansible sudo apt-get update sudo apt-get install -y ansible<\/p>\n
To validate the installation, execute the following ansible command.<\/p>\n
ansible --version<\/code><\/pre>\n![\"verifying](\"https:\/\/storage.ghost.io\/c\/5f\/2f\/5f2f4d20-2abf-4534-8d40-7aa233aedd43\/content\/images\/2025\/03\/image-10-41.png\")
<\/figure>\nConfiguring Ansible Inventory<\/h2>\n
All the servers that have to be managed using Ansible are called Ansible hosts<\/strong>.<\/p>\n
Configure ansible.cfg<\/h3>\n
Ansible loads the configuration from the
ansible.cfg<\/code><\/strong> file located in the following locations. The file precedence is as per the order given below.<\/p>\n- \n
- ANSIBLE_CONFIG env variable<\/li>\n
- .\/ansible.cfg (current directory)<\/li>\n
- ~\/.ansible.cfg (home directory)<\/li>\n
- \/etc\/ansible\/ansible.cfg<\/li>\n<\/ol>\n
Open
\/etc\/ansible\/ansible.cfg<\/code><\/strong> file and add the following.<\/p>\n[defaults]\ninventory = \/etc\/ansible\/inventory.ini\nhost_key_checking = False<\/code><\/pre>\nHere we have mentioned two default configurations.<\/p>\n
- \n
- inventory<\/strong>: Location of the inventory file. Which we will discuss in the next section.<\/li>\n
- host_key_checking:<\/strong> It disables the ssh host key checking when ansible tries to ssh into the remote machine.<\/li>\n<\/ol>\n
Configure Ansible Inventory<\/h3>\n
Ansible keeps track of the hosts using the inventory file ( A file with the list of servers). It has the host the IP address\/domain name with username, password, or SSH key<\/a> information to connect to the node.<\/p>\n
In every environment the servers are segregated as web group, DB group, app group, etc.. we can have similar segregation in our inventory file using labels. It is a recommended way of managing servers.<\/p>\n
For instance, you might have dev, test, and prod servers. In this case, you can group servers from different environments under different labels.<\/p>\n
By default, the inventory file named hosts is present in
\/etc\/ansible\/<\/code><\/strong> directory. If you open the\/etc\/ansible\/hosts<\/code><\/strong> you will find the sample host entries. Let’s keep this file as a backup and create our own host file.<\/p>\nLet’s create our own inventory file named
inventory.ini <\/code>as we mentioned in theansible.cfg<\/code> file.<\/p>\nsudo vi \/etc\/ansible\/inventory.ini<\/code><\/pre>\nMy ansible host’s IP addresses are
192.168.2.30<\/code><\/strong> and192.168.2.40<\/code><\/strong> and I will be using them throughout the example. Replace it with your host’s IP address. So I am adding it under the dev label. Modify the IP and label as per your requirements.<\/p>\n[dev]\n192.168.2.30\n192.168.2.40\n\n[dev:vars]\nansible_user=ubuntu\nansible_ssh_pass=vargrant \nansible_private_key_file=\/path\/to\/key.pem\n\n[all:vars]\nansible_user=ubuntu\nansible_ssh_pass=vargrant \nansible_private_key_file=\/path\/to\/key.pem\n\n[local]\n127.0.0.1<\/code><\/pre>\n[dev:vars]<\/strong><\/code> parameters are applied to the servers under the dev label. As we know that Ansible uses ssh for connecting to hosts. So we need to specify the username<\/strong>, password, or ssh key of those hosts.<\/p>\nIf all the servers have the same username and password\/ssh-key, you can mention it in
dev:vars<\/code><\/strong> label. <\/p>\nIf not you can specify it with the IP addresses separated by space as shown below.<\/p>\n
192.168.2.30 ansible_user=vagrant ansible_ssh_pass=vargrant<\/p>\n
[all:vars]<\/code><\/strong> The parameters added under this label will be applicable to all the servers mentioned in the inventory file. It is the global variable for all the servers under different labels.<\/p>\nThe local label<\/strong> represents the Ansible server itself. So if you want to run a playbook on your ansible server, you can make use of the local label.<\/p>\n
Test Remote Connection Using Ansible Ad-Hoc Command<\/h2>\n
Now we have every Configuration in place. Let’s test our configuration using the following command.<\/p>\n
ansible all -m ping<\/p>\n
You should get the following success message.<\/p>\n
vagrant@acs:\/etc\/ansible$ ansible all -m ping\n192.168.2.30 | SUCCESS => {\n \"changed\": false,\n \"ping\": \"pong\"\n}\n192.168.2.40 | SUCCESS => {\n \"changed\": false,\n \"ping\": \"pong\"\n}<\/code><\/pre>\nImportant Ansible Commands<\/h2>\n
You can check the configured inventory list using the following command.<\/p>\n
ansible-inventory --list -y<\/code><\/pre>\n![\"ansible](\"https:\/\/storage.ghost.io\/c\/5f\/2f\/5f2f4d20-2abf-4534-8d40-7aa233aedd43\/content\/images\/2025\/03\/image-11-36.png\")
Click to view in HD<\/span><\/figcaption><\/figure>\n Run ad-hoc commands on all the servers in the inventory.<\/p>\n
ansible all -b -m apt -a \"name=vim state=latest\" <\/code><\/pre>\nConclusion<\/h2>\n
When it comes to configuration management,<\/a> Ansible is one of the best options for devops engineers<\/a>. Also when it comes to immutable infrastructure<\/a>, you can use ansible along with tools like packer to create deployable VM images.<\/p>\n
Wheater it is cloud or on-prem, Ansible provides good options for provisioning and configuration management. It can be easily integrated with the CI\/CD systems as well.<\/p>\n
\n - host_key_checking:<\/strong> It disables the ssh host key checking when ansible tries to ssh into the remote machine.<\/li>\n<\/ol>\n
- inventory<\/strong>: Location of the inventory file. Which we will discuss in the next section.<\/li>\n