Ansible Get_URL Module: Download Files From a Specific URL

The get_url modules allows Ansible to download files from specified URLs and save them to a local or remote machine. This is particularly useful when working with remote servers, as it eliminates the need to manually download and transfer files.

Key benefits include:

• Direct downloads from public and private URLs.
• Support for checksum verification (an integrity check).
• Flexibility in handling HTTP headers, proxies, and other request parameters.

In this article, we will dive deep into the Ansible get_url module with examples.

Basic Syntax

Hre’s  the basic code syntax:

- name: Download a file using get_url
  hosts: all
  tasks:
    - name: Download file to destination
      ansible.builtin.get_url:
        url: URL
        dest: destination_path
        checksum: checksum_value
        mode: permissions
        owner: file_owner
        group: file_group

Here’s the explanation:

• url: The URL from which the file can be retrieved (must be provided as a string).
• dest: The directory path where the file should be saved.
• checksum: Expected checksum of the file for validation.
• mode: Permissions for the file.
• owner and group: File ownership details.

Example 1: Downloading a File to a Remote Host

This example demonstrates downloading a publicly available file to a remote host.

- name: Download a file to a remote host
  hosts: webservers
  tasks:
    - name: Download file from URL
      ansible.builtin.get_url:
        url: https://example.com/sample.zip
        dest: /tmp/sample.zip

In this example playbook:

• The url parameter specifies the file’s source URL.
• The dest parameter specifies the destination path on the target host.

Example 2: Downloading a File with Checksum Verification

Adding checksum validation ensures that the downloaded file matches the expected integrity.

- name: Download a file with checksum validation
  hosts: webservers
  tasks:
    - name: Download file and verify checksum
      ansible.builtin.get_url:
        url: https://example.com/sample.zip
        dest: /tmp/sample.zip
        checksum: "sha256:3b8c33fd6d8985f82c2c1e59ab17d885a3ad5670c3e21968e2e98b840db8ed9b"

In this example:

• The checksum parameter ensures that the file integrity is verified. An error occurs if the checksum doesn’t match.

Example 3: Downloading a File with HTTP Authentication

In this example, we download a file from a secured server using HTTP Basic Authentication.

- name: Download a file with authentication
  hosts: webservers
  tasks:
    - name: Download secure file
      ansible.builtin.get_url:
        url: https://secure.example.com/secure-file.zip
        dest: /opt/secure-file.zip
        url_username: user123
        url_password: pass123

Here:

• The url_username and url_password parameters provide basic authentication.

Example 4: Skipping Download if the File Exists

To avoid redundant downloads, set the force parameter to no.

- name: Avoid redundant downloads
  hosts: webservers
  tasks:
    - name: Download only if file is missing
      ansible.builtin.get_url:
        url: https://example.com/sample.zip
        dest: /tmp/sample.zip
        force: no

In the above example:

• The force: no parameter ensures the file is only downloaded if it does not exist.

Example 5: Using Proxies for Downloads

This example demonstrates downloading a file via an HTTP proxy.

- name: Download file using a proxy
  hosts: webservers
  tasks:
    - name: Download via proxy
      ansible.builtin.get_url:
        url: https://example.com/sample.zip
        dest: /tmp/sample.zip
        http_proxy: http://proxy.example.com:3128
        validate_certs: no

In this playbook:

• The http_proxy parameter specifies the proxy server.
• The validate_certs: no parameter disables certificate validation for untrusted proxies.

Conclusion

The get_url module is an essential feature in Ansible for automating file downloads. By leveraging its features like authentication, checksum validation, and proxy support, you can ensure secure and efficient file transfers in your automation workflows.

To enhance your playbooks, consider using:

• failed_when to define custom failure conditions
• loop to iterate over multiple URLs
• debug to troubleshoot and verify values
• ignore_errors to allow continued execution despite task failures.

FAQs