Ansible variables

Ansible variables are dynamic values used within Ansible playbooks and roles to enable customization, flexibility, and reusability of configurations. Ansible variables are very similar to variables in programming languages, ansible variables, helping you manage complex tasks more efficiently by allowing the same playbook or role to be applied across different environments, systems, or contexts without the need for hardcoding specific information.

The concept of variables in Ansible is similar to that of variables in any programming language. In Ansible a value is assigned to a variable that can be then referenced in a playbook or on command line during playbook runtime. Variables can be used in playbooks , inventories , and at the command line as we have just mentioned. Variable names can only contain letters uppercase or lowercase letters or a combination of the two , underscores, and digits. In defining variables, some strings are reserved for special purposes and cannot qualify as valid variable names.

Ansible variables

You are reading an unmaintained version of the Ansible documentation. Unmaintained Ansible versions can contain unfixed security vulnerabilities CVE. Please upgrade to a maintained version. See the latest Ansible documentation. While automation exists to make it easier to make things repeatable, all of your systems are likely not exactly alike. On some systems you may want to set some behavior or configuration that is slightly different from others. Also, some of the observed behavior or state of remote systems might need to influence how you configure those systems. Such as you might need to find out the IP address of a system and even use it as a configuration value on another system. You might have some templates for configuration files that are mostly the same, but slightly different based on those variables. For best practices advice, refer to Variables and Vaults in the Best Practices chapter.

For example:. Another useful option is to store key-value pairs in variables as dictionaries.

With Ansible you can retrieve or discover certain variables containing information about your remote systems or about Ansible itself. Variables related to remote systems are called facts. With facts, you can use the behavior or state of one system as a configuration on other systems. For example, you can use the IP address of one system as a configuration value on another system. Variables related to Ansible are called magic variables. Package requirements for fact gathering. Information about Ansible: magic variables.

In Ansible, variables are used to store and retrieve values that can be referenced in playbooks, roles, templates, and other Ansible components. They provide a way to make playbooks more flexible and reusable by allowing you to parameterize your configurations. Dynamic Configurations: Variables enable you to create dynamic configurations based on the values assigned at runtime. This is useful for adapting configurations to different environments or changing requirements. Reusability: Variables promote playbook and role reusability. By defining variables, you can create generic playbooks and roles that can be easily adapted to different scenarios without modifying the underlying code. Readability: Variables enhance the readability of your playbooks. Instead of hardcoding values, you can use descriptive variable names to make your playbooks more understandable and maintainable. Parameterization: Variables allow you to parameterize your playbooks, making it easier to customize configurations for specific use cases or environments.

Ansible variables

For community users, you are reading an unmaintained version of the Ansible documentation. Unmaintained Ansible versions can contain unfixed security vulnerabilities CVE. Please upgrade to a maintained version. See the latest Ansible community documentation. Creating valid variable names. Defining variables in inventory.

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Magic Variables Magic Variables are automatically created by Ansible and cannot be changed by a user. Using advanced variable syntax. Since Ansible provides a plethora of options to define variables, it might be a bit confusing to figure out the best way and place to set them. However, unlike registered variables, facts can be gathered independently and cached for repeated use. Non-SSH based types are described in the next section. If you want to use it in the same play where you created it, you must explicitly re-run the setup module. When you pass multiple inventory sources at the command line, Ansible merges variables in the order you pass those parameters. If openstack. You can define these variables in your playbooks, in your inventory , in reusable files or roles , or at the command line. Suppose you have a list of student names to be printed to stdout. To configure fact caching using redis, enable it in ansible.

Ansible is not a full-fledged programming language, but it does have several programming language features, and one of the most important of these is variable substitution. There are different types of variables available in Ansible you can click on individual link which will take you to the respective official documentation page from docs. The following examples are all invalid, however, and cannot be used :.

Fact caching could be configured to run nightly, but configuration of a small set of servers could run ad-hoc or periodically throughout the day. This can be useful for combining static and dynamic hosts and managing them as one inventory. The setup module in Ansible automatically discovers a standard set of facts about each host. Each of the items in the loop is referenced by the variable. Variable in playbooks are very similar to using variables in any programming language. You can see that one. Unique values like non-standard SSH ports work well as host variables. You can use groups and hostvars together to find all the IP addresses in a group. The most basic usage of variables is to define a variable using a single value in the playbook YAML file. This is particularly useful when writing a generic release playbook where you may want to pass in the version of the application to deploy:. How do I access a variable of the first host in a group? More about me. If you are using a version of Ansible prior to 2. First, we have the global scope where the values are set for all hosts.