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Output variables for Ansible

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Output variables allow you to export data from Ansible playbook execution to other steps in the stage or anywhere in the pipeline. This page explains how to configure output variables for Ansible playbooks in Harness.

Export variables from an Ansible playbook​

To export variables from an Ansible playbook, write key-value pairs to the DRONE_OUTPUT file using the ansible.builtin.lineinfile module.

Example playbook​

---
- name: Fetch system info from remote host and export to Harness
  hosts: all
  gather_facts: true

  tasks:
    - name: Show remote OS info
      ansible.builtin.debug:
        msg: "Remote host {{ inventory_hostname }} is running {{ ansible_distribution }} {{ ansible_distribution_version }}"

    - name: Export OS to Harness output variable
      ansible.builtin.lineinfile:
        path: "{{ lookup('ansible.builtin.env', 'DRONE_OUTPUT') }}"
        line: "REMOTE_OS={{ ansible_distribution }} {{ ansible_distribution_version }}"
        create: true
        insertafter: EOF
      delegate_to: localhost
      run_once: true

Key points:

  • DRONE_OUTPUT path: Use lookup('ansible.builtin.env', 'DRONE_OUTPUT') to get the output file path.
  • Format: Write variables as VARIABLE_NAME=value.
  • delegate_to: Use delegate_to: localhost to write to the file on the control node, not remote hosts.
  • run_once: Use run_once: true when exporting from multiple hosts to avoid duplicate writes.

Export multiple variables​

You can export multiple variables by writing additional lines to DRONE_OUTPUT:

- name: Export multiple variables
  ansible.builtin.lineinfile:
    path: "{{ lookup('ansible.builtin.env', 'DRONE_OUTPUT') }}"
    line: "{{ item }}"
    create: true
    insertafter: EOF
  loop:
    - "REMOTE_OS={{ ansible_distribution }} {{ ansible_distribution_version }}"
    - "REMOTE_IP={{ ansible_default_ipv4.address }}"
    - "REMOTE_ARCH={{ ansible_architecture }}"
    - "REMOTE_MEMORY_MB={{ ansible_memtotal_mb }}"
  delegate_to: localhost
  run_once: true

Each variable will be available as a separate output variable in Harness.

Reference output variables​

Once exported, output variables can be referenced in subsequent pipeline steps using Harness expressions.

Within the same stage:

<+execution.steps.[step_id].output.outputVariables.[output_variable_name]>

Anywhere in the pipeline:

<+pipeline.stages.[stage_id].spec.execution.steps.[step_id].output.outputVariables.[output_variable_name]>

When step is inside a step group:

<+pipeline.stages.[stage_id].spec.execution.steps.[step_group_id].steps.[step_id].build.[output_variable_name]>

To find the expression to reference your output variables, find the step in the pipeline execution, and click the Output tab.

Example usage​

After running the playbook above, you can reference the REMOTE_OS variable in a subsequent step:

- step:
    type: ShellScript
    name: Display Remote OS
    identifier: display_os
    spec:
      shell: Bash
      source:
        type: Inline
        spec:
          script: |
            echo "Deployed to: <+execution.steps.ansible_deploy.output.outputVariables.REMOTE_OS>"