Book Image

Mastering Ansible, 4th Edition - Fourth Edition

By : James Freeman, Jesse Keating
Book Image

Mastering Ansible, 4th Edition - Fourth Edition

By: James Freeman, Jesse Keating

Overview of this book

Ansible is a modern, YAML-based automation tool (built on top of Python, one of the world’s most popular programming languages) with a massive and ever-growing user base. Its popularity and Python underpinnings make it essential learning for all in the DevOps space. This fourth edition of Mastering Ansible provides complete coverage of Ansible automation, from the design and architecture of the tool and basic automation with playbooks to writing and debugging your own Python-based extensions. You'll learn how to build automation workflows with Ansible’s extensive built-in library of collections, modules, and plugins. You'll then look at extending the modules and plugins with Python-based code and even build your own collections — ultimately learning how to give back to the Ansible community. By the end of this Ansible book, you'll be confident in all aspects of Ansible automation, from the fundamentals of playbook design to getting under the hood and extending and adapting Ansible to solve new automation challenges.
Table of Contents (18 chapters)
Section 1: Ansible Overview and Fundamentals
Section 2: Writing and Troubleshooting Ansible Playbooks
Section 3: Orchestration with Ansible

Debugging code execution

Sometimes, the logging and inspection of variable data are not enough to troubleshoot a problem. When this happens, it can be necessary to interactively debug the playbook, or to dig deeper into the internals of Ansible code. There are two main sets of Ansible code: code that runs locally on the Ansible host, and module code that runs remotely on the target host.

Playbook debugging

Playbooks can be interactively debugged by using an execution strategy that was introduced in Ansible 2.1, the debug strategy. If a play uses this strategy when an error state is encountered, an interactive debugging session starts. This interactive session can be used to display variable data, display task arguments, update task arguments, update variables, redo task execution, continue execution, or exit the debugger.

Let's demonstrate this with a play that has a successful task, followed by a task with an error, followed by a final successful...