Ansible Journey 3: Running Ansible Commands Manually

Note: If you are also following the videos, you will notice that I skipped video #3. This covers the use of Git, which while useful is not required for the tutorial.

This covers executing an ansible command manually. While this is not a good way to leverage the core features of an Ansible-managed environment, it does provide useful output that can be used for testing, and to illustrate how Ansible functions.

The most basic command is the Ansible ping command. This is not an ICMP ping that we are used to in Unix environments. Rather this is a test performed using Ansible that checks to see if a node can receive and execute commands. Figure 3.1 shows the output (in green) of ansible ping. The first command explicitly states which files Ansible should use when executing the commands. The second demonstrates the same where the files are saved in Ansible’s configuration (discussed below). Of note is the “SUCCESS” string and the word “pong.” If the ping fails, the output will be in a different color, and will provide some details on why it failed.

Figure 3.1: The ansible ping command

 The following parameters can be used at the command line:

Parameter	Purpose
all	Specifies that this action will take place on all hosts in the inventory file.
-i <file>	Inventory file containing hosts upon which Ansible can operate
-m	module component that contains the code to support execution of certain commands.
--key-file <file>	Specifies the private key file to use.

The ansible.cfg file allows you to set up defaults when running ansible. Figure 3.2 shows this file.

Figure 3.2: A simple ansible.cfg file.

Key	Value
inventory	Specify the inventory file to use; searches local path first.
private_key_file	Specify the private key to use in the connection

There is a default ansible.cfg and a hosts file that exist under /etc/ansible as defaults (created during installation). These can be overridden using the ansible.cfg file above.

If you want to perform a test and minimize output, you can run ansible against a single file using the limit parameter:

--limit <IP|hostname>

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