![]() Should you want to invert the architecture of Ansible, so that nodes check in to a central location, instead Use the -verbose flag when running your playbook to see detailed output from successful modules as well as unsuccessful ones. To run your playbook, use the ansible-playbook command. If you are unsure, test your playbooks in a sandbox environment before running them multiple times in production. However, not all playbooks and not all modules behave this way. ![]() Modules that behave this way are often called ‘idempotent.’ Whether you run a playbook once, or multiple times, the outcome should be the same. Most Ansible modules check whether the desired final state has already been achieved, and exit without performing any actions if that state has been achieved, so that repeating the task does not change the final state. General failures and fatal “unreachable” communication attempts are kept separate in the counts. At the bottom of the playbook execution, Ansible provides a summary of the nodes that were targeted and how they performed. When you run a playbook, Ansible returns information about connections, the name lines of all your plays and tasks, whether each task has succeeded or failed on each machine, and whether each task has made a change on each machine. If a task fails on a host, Ansible takes that host out of the rotation for the rest of the playbook. Within each play, Ansible applies the same task directives to all hosts. You can use strategies to change this default behavior. When a task has executed on all target machines, Ansible moves on to the next task. ![]() Each task executes a module with specific arguments. Task execution īy default, Ansible executes each task in order, one at a time, against all machines matched by the host pattern. Learning the precedence rules for these sources of data will help you as you expand your Ansible ecosystem. To support a variety of environments, Ansible lets you set many of these parameters as command-line flags, in your Ansible configuration, or in your inventory. Playbook keywords can control the connection plugin, whether to use privilege escalation, how to handle errors, and more. You can add other Playbook Keywords at the playbook, play, or task level to influence how Ansible behaves. This is the user account for the SSH connection. For example, the playbook above sets a remote_user for each play. Your playbook can include more than just a hosts line and tasks. name : Update web servers hosts : webservers remote_user : root tasks : - name : Ensure apache is at the latest version : name : httpd state : latest - name : Write the apache config file : src : /srv/httpd.j2 dest : /etc/nf - name : Update db servers hosts : databases remote_user : root tasks : - name : Ensure postgresql is at the latest version : name : postgresql state : latest - name : Ensure that postgresql is started : name : postgresql state : started The managed nodes to target, using a pattern At a minimum, each play defines two things: Playbooks with multiple ‘plays’ can orchestrate multi-machine deployments, running one play on your webservers, then another play on your database servers, then a third play on your network infrastructure, and so on. Within each play, tasks also run in order from top to bottom. Playbook execution Ī playbook runs in order from top to bottom. Each play executes part of the overall goal of the playbook, running one or more tasks. The terms ‘playbook’ and ‘play’ are sports analogies. If you are not familiar with YAML, look at our overview of YAML Syntax and consider installing an add-on for your text editor (see Other Tools and Programs) to help you write clean YAML syntax in your playbooks.Ī playbook is composed of one or more ‘plays’ in an ordered list. Playbooks are expressed in YAML format with a minimum of syntax. ![]() Launch tasks synchronously or asynchronously ![]() Orchestrate steps of any manual ordered process, on multiple sets of machines, in a defined order You may want to look at these in another tab as you read the documentation. The playbooks in the ansible-examples repository illustrate many useful techniques. Then you can use the playbook to push out new configuration or confirm the configuration of remote systems. If you need to execute a task with Ansible more than once, write a playbook and put it under source control. Controlling how Ansible behaves: precedence rulesĪnsible Playbooks offer a repeatable, re-usable, simple configuration management and multi-machine deployment system, one that is well suited to deploying complex applications.Virtualization and Containerization Guides.Protecting sensitive data with Ansible vault. ![]()
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