Book Image

Learning Ansible 2 - Second Edition

Book Image

Learning Ansible 2 - Second Edition

Overview of this book

Ansible is an open source automation platform that assists organizations with tasks such as configuration management, application deployment, orchestration, and task automation. With Ansible, even complex tasks can be handled easier than before. In this book, you will learn about the fundamentals and practical aspects of Ansible 2 by diving deeply into topics such as installation (Linux, BSD, and Windows Support), playbooks, modules, various testing strategies, provisioning, deployment, and orchestration. In this book, you will get accustomed with the new features of Ansible 2 such as cleaner architecture, task blocks, playbook parsing, new execution strategy plugins, and modules. You will also learn how to integrate Ansible with cloud platforms such as AWS. The book ends with the enterprise versions of Ansible, Ansible Tower and Ansible Galaxy, where you will learn to interact Ansible with different OSes to speed up your work to previously unseen levels By the end of the book, you’ll able to leverage the Ansible parameters to create expeditious tasks for your organization by implementing the Ansible 2 techniques and paradigms.
Table of Contents (16 chapters)
Learning Ansible 2 Second Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface

Delegating a task


Sometimes you want to execute an action on a different system. This could be, for instance, a database node while you are deploying something on an application server node or to the local host. To do so, you can just add the 'delegate_to: HOST' property to your task and it will be run on the proper node. Let's rework the previous example to achieve this:

    --- 
    - hosts: database 
      remote_user: ansible 
      tasks: 
      - name: Count processes running on the remote system 
        shell: ps | wc -l 
        register: remote_processes_number 
      - name: Print remote running processes 
        debug: 
          msg: '{{ remote_processes_number.stdout }}' 
      - name: Count processes running on the local system 
        shell: ps | wc -l 
        delegate_to: localhost 
        register: local_processes_number 
      - name: Print local running processes 
        debug: 
          msg: '{{ local_processes_number.stdout }}' 

Saving it as delegate_to.yaml, we...