Comprehensive Guide to Ansible’s become Keyword

Ansible, a leading infrastructure automation tool, offers the become keyword for managing privilege escalation securely. This feature simplifies administrative tasks by automating elevated permissions while ensuring consistency, flexibility, and adherence to the principle of least privilege.

In this article, we’ll delve into:

• Understanding become and its importance
• Applying become in tasks and playbooks
• Using advanced parameters like become_user and become_method
• Common mistakes and best practices
• Leveraging Ansible Vault and Spacelift for secure and efficient workflows.

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What is become in Ansible?

In Linux, privilege escalation typically involves the sudo command for executing administrative tasks. Ansible’s become feature mirrors this, providing a structured way to elevate permissions for tasks or entire playbooks without hardcoding credentials.

Key Benefits of Using become:

• Security: Clearly defined tasks needing privileges reduce unnecessary access.
• Flexibility: Supports multiple privilege escalation methods across environments.
• Consistency: Centralized management for secure task execution.

By default, become uses the sudo method and escalates to the root user. However, it supports alternatives like runas (Windows), doas, and pbrun, configurable in the ansible.cfg file or task-level parameters.

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Applying become in Playbooks

1. Using become in Specific Tasks

To enable privilege escalation for an individual task, add the become: true parameter.

Example: Installing Applications

Example: Copying Files to Protected Directories

2. Applying become Across a Playbook

If most tasks require elevated privileges, set become: true at the playbook level:

This approach reduces repetition and simplifies playbooks but should be used judiciously to avoid over-escalation.

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Advanced become Usage with become_user and become_method

Switching Users with become_user

By default, become escalates to the root user. To target specific accounts, use the become_user parameter:

Common Scenarios:

• Deploying applications with service accounts (e.g., Tomcat).
• Managing database resources with privileged users (e.g., Postgres).
• Running application-specific tasks under non-root users.

Changing Escalation Methods with become_method

The become_method parameter defines how privilege escalation occurs. For example, use runas on Windows or pbrun for enhanced security:

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Running ansible-playbook with become

When executing playbooks that use become, the command requires specific flags:

1. Passwordless Sudo: Simply use --become.

ansible-playbook playbook.yml --become

       2. Prompt for Password: Add --ask-become-pass for environments requiring authentication.

ansible-playbook playbook.yml --become --ask-become-pass

       3. Automated Passwords: Supply a password file with --become-password-file for CI/CD workflows.

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Common Mistakes and Best Practices

Mistakes to Avoid:

1. Forgetting become:
   • Missed tasks requiring escalation lead to runtime failures.
   • Solution: Test in non-production environments to identify privileged tasks.
2. Incorrect become_user:
   • Assigning a task to an unconfigured user results in failures.
   • Solution: Ensure target users are configured in the sudoers file.
3. Hardcoding Passwords:
   • This poses a significant security risk.
   • Solution: Use Ansible Vault or password files with restricted access.
4. Using Default Escalation Methods:
   • Incorrect methods (e.g., using sudo where runas is required) cause errors.
   • Solution: Test methods per environment and configure them globally in ansible.cfg.

Best Practices:

• Minimize Escalation: Use become only when necessary.
• Group Tasks: Organize privileged tasks in roles for clarity.
• Encrypt Sensitive Data: Leverage Ansible Vault for passwords and credentials.
• Test Extensively: Validate tasks in staging environments before production.

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Key Takeaways

The become keyword is a cornerstone of Ansible’s privilege management, enabling secure and flexible task execution. By using advanced features like become_user and become_method, you can tailor privilege escalation to meet diverse requirements across systems. Following best practices and leveraging tools like Spacelift ensures that your Ansible projects remain secure, maintainable, and efficient.

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