Exercise 1.0: Exploring the lab environment¶

Ansible is an open-source automation engine for software provisioning, configuration management and application-deployment. It allows for agent-less system configuration, which means it does not deploy agents to nodes. Communication to those nodes works by using SSH and Python is a requirement on those managed nodes. This makes that communication to managed nodes can be secure. Python is used to support the modules which support the tasks which will get deployed by Ansible through the use of so-called playbooks.

When Ansible gets installed it will contain an initial ‘Ansible configuration file’ called ansible.cfg file which includes the inventory of hosts and where the library of modules can be found.

Let’s start to explore by walking through the steps.

Step 1

Navigate to the networking-workshop directory.

[student1@ansible ~]$ cd networking-workshop/
[student1@ansible networking-workshop]$

Step 2

Run the ansible command with the --version command to look at what is configured:

[student1@ansible networking-workshop]$ ansible --version
ansible 2.6.2
   config file = /home/student1/.ansible.cfg
   configured module search path = [u'/home/student1/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
   ansible python module location = /usr/lib/python2.7/site-packages/ansible
   executable location = /usr/bin/ansible
   python version = 2.7.5 (default, May  3 2017, 07:55:04) [GCC 4.8.5 20150623 (Red Hat 4.8.5-14)]

Note

The Ansible version you see might differ from the above output

This command gives you information about the version of Ansible, location of the executable, version of Python, search path for the modules and location of the ansible configuration file.

Step 3

Use the cat command to view the contents of the ansible.cfg file.

[student1@ansible networking-workshop]$ cat ~/.ansible.cfg
[defaults]
connection = smart
timeout = 60
inventory = /home/student1/networking-workshop/lab_inventory/hosts
host_key_checking = False
[student1@ansible networking-workshop]$

Note

The following parameters within the ansible.cfg file:

inventory: shows the location of the Ansible inventory being used.
private_key_file: this shows the location of the private key used to login to devices

Step 4

The scope of a play within a playbook is limited to the groups of hosts declared within an Ansible inventory. Ansible supports multiple inventory types. An inventory could be a simple flat file with a collection of hosts defined within it or it could be a dynamic script (potentially querying a CMDB backend) that generates a list of devices to run the playbook against.

In this lab you will work with a file based inventory written in the ini format. Use the cat command to view the contents of your inventory:

[student1@ansible networking-workshop]$ cat lab_inventory/hosts

The output will look as follows with student2 being the respective student workbench:

[all:vars]
ansible_user=student2
ansible_ssh_pass=ansible
ansible_port=22
[lb]
f5 ansible_host=34.199.128.69 ansible_user=admin private_ip=172.16.26.136 ansible_ssh_pass=admin
[control]
ansible ansible_host=107.23.192.217 ansible_user=ec2-user private_ip=172.16.207.49

[webservers]
host1 ansible_host=107.22.141.4 ansible_user=ec2-user private_ip=172.16.170.190
host2 ansible_host=54.146.162.192 ansible_user=ec2-user private_ip=172.16.160.13

Step 5

In the above output every [ ] defines a group. For example [webservers] is a group that contains the hosts host1 and host2.

Note

A group called all always exists and contains all groups and hosts defined within an inventory.

We can associate variables to groups and hosts. Host variables are declared/defined on the same line as the host themselves. For example for the host f5:

f5 ansible_host=34.199.128.69 ansible_user=admin private_ip=172.16.26.136 ansible_ssh_pass=admin

f5 - The name that Ansible will use. This can but does not have to rely on DNS
ansible_host - The IP address that ansible will use, if not configured it will default to DNS
ansible_user - The user ansible will use to login to this host, if not configured it will default to the user the playbook is run from
private_ip - This value is not reserved by ansible so it will default to a host variable.This variable can be used by playbooks or ignored completely.
ansible_ssh_pass - The password ansible will use to login to this host, if not configured it will assume the user the playbook ran from has access to this host through SSH keys.

Does the password have to be in plain text? No, Red Hat Ansible Tower can take care of credential management in an easy to use web GUI or a user may use ansible-vault

[student1@ansible networking-workshop]$ cd ~

You have finished this exercise

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