In this tutorial, I will introduce Ansible variables and explore their usage with examples.<\/p>\n<\/p>\n
To proceed with this tutorial, you will need the following:<\/p>\n<\/p>\n
Check out our introductory articles in this Ansible beginner’s tutorial<\/a>, where we explain how to configure the necessary prerequisites.<\/p>\n<\/p>\n You can use variables in inventory files to define properties specific to hosts or groups. This helps in making your playbooks more flexible and reusable.<\/p>\n<\/p>\n Let’s create an inventory.txt<\/em> file with the following content.<\/p>\n<\/p>\n webserver1 ansible_host=192.168.1.101<\/p> webserver2 ansible_host=192.168.1.102<\/p> [db]<\/p> dbserver1 ansible_host=192.168.1.201<\/p> [web:vars]<\/p> http_port=80<\/p> user=admin<\/p> <\/pre>\n<\/p>\n In this example, http<\/em>port and <\/em>user are group variables defined under the <\/em>[web:vars] section. These variables will apply to all hosts under the <\/em>[web] group.<\/em><\/p>\n<\/p>\n After defining variables in your inventory file, you can use them in your Ansible playbooks.<\/p>\n<\/p>\n Create a playbook.yaml <\/em>file and add the following content:<\/p>\n<\/p>\n ---<\/p> - hosts: web<\/p> tasks:<\/p> - name: Print HTTP port<\/p> debug:<\/p> msg: \"HTTP Port is {{ http_port }}\"<\/p> - name: Print username<\/p> debug:<\/p> msg: \"Username is {{ user }}\"<\/p> <\/pre>\n<\/p>\n In this playbook, {{ http_port }} and {{ user }}<\/em> variables in the playbook will be substituted with the values defined in your inventory for the web hosts group. Now, run the playbook using the following command.<\/p>\n<\/p>\n You will see the values of the {{ httpport }} and {{ user }}<\/em> variables in the following screen.<\/p>\n<\/p>\n Showing the value of variables defined in an inventory file<\/a><\/p>\n You can define variables directly within a task. Let’s create a playbook.yaml<\/em> file with the following content:<\/p>\n<\/p>\n ---<\/p> - hosts: db<\/p> vars:<\/p> db_port: 3306<\/p> user: \"root\"<\/p> tasks: <\/p> - name: Print database port<\/p> debug:<\/p> msg: \"Database Port is {{ db_port }}\"<\/p> - name: Print username<\/p> debug:<\/p> msg: \"Username is {{ user }}\"<\/p> <\/pre>\n<\/p>\n Now, run the playbook using the following command.<\/p>\n<\/p>\n ansible-playbook -i inventory.txt playbook.yaml<\/p> <\/pre>\n<\/p>\n You will see the values of variables {{ dbport }} <\/em> and {{ user }} <\/em> on the following screen. Showing the value of variables defined within a tasks<\/a><\/p>\n You can define variables in separate YAML files and include them in the playbook using the vars_files<\/em> directive.<\/p>\n<\/p>\n Let’s create a playbook.yaml <\/em>file and add the following content.<\/p>\n<\/p>\n ---<\/p> - name: Playbook with Variable Files<\/p> hosts: db<\/p> vars_files:<\/p> - vars_file.yaml<\/p> tasks:<\/p> - name: Task using variable from file<\/p> debug:<\/p> msg: \"The value of variable is {{ var }}\"<\/p> <\/pre>\n<\/p>\n Next, create a vars<\/em>file.yaml in your current working directory and add the following content: var: \"value from file\"<\/p> <\/pre>\n<\/p>\n Now, run the playbook using the following command.<\/p>\n<\/p>\n This will fetch the value of the var variable from the varsfile.yaml <\/em> file and print it on the screen. <\/p>\n<\/p>\n Showing the value of variables defined in a file<\/a><\/p>\n Ansible facilitates prompting for variable input during playbook execution with the help of the vars_prompt<\/em> section.<\/p>\n<\/p>\n Proceed by creating a playbook.yaml<\/em> and include the subsequent content:<\/p>\n<\/p>\n ---<\/p> - name: Playbook with Prompted Variables<\/p> hosts: db<\/p> vars_prompt:<\/p> - name: user_input<\/p> prompt: \"Enter a value:\"<\/p> tasks:<\/p> - name: Task using prompted variable<\/p> debug:<\/p> msg: \"You entered: {{ user_input }}\"<\/p> <\/pre>\n<\/p>\n Now, run the playbook using the following command.<\/p>\n<\/p>\n <\/pre>\n<\/p>\n You will be prompted to enter a value, which will then appear on the screen.<\/p>\n<\/p>\nUse variables in inventories<\/h2>\n<\/p>\n
[web]<\/p>
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<\/em><\/p>\n<\/p>\nansible-playbook -i inventory.txt playbook.yaml<\/pre>\n<\/p>\n
Use variables within a task in playbooks<\/h2>\n<\/p>\n
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<\/em><\/p>\n<\/p>\nUse variables in files<\/h2>\n<\/p>\n
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ansible-playbook -i inventory.txt playbook.yaml<\/pre>\n<\/p>\n
Use variables with prompts<\/h2>\n<\/p>\n
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ansible-playbook -i inventory.txt playbook.yaml<\/p>