AHMED ZBYR

AHMED ZBYR

Biker, EV Enthusiast

Ansible is a powerful automation tool that simplifies infrastructure management and application deployment. However, like any technology, it’s easy to make mistakes, especially when you’re just starting out. This post outlines five common Ansible mistakes and provides guidance on how to avoid them, ensuring smoother and more efficient automation workflows.

1. Overusing the command or shell Module

The Mistake: New Ansible users often resort to the command or shell module for everything, even when more specific modules exist. While these modules offer flexibility, they should be reserved for cases where no suitable specialized module is available.

Why it’s bad:

  • Idempotency Issues: command and shell modules don’t inherently guarantee idempotency. Running the same task multiple times might lead to unintended side effects.
  • Security Risks: Using shell can introduce security vulnerabilities, especially when constructing commands with user-provided input.
  • Reduced Readability: Playbooks become harder to understand and maintain when filled with complex shell commands.
  • Missing Features: Specialized modules often provide features like built-in error handling, idempotency checks, and simpler syntax.

How to avoid it:

  • Explore Ansible’s Modules: Before using command or shell, search for a more specific module that meets your needs. For example, use apt, yum, or package for package management, user for user management, file for file manipulation, and so on.
- name: Install the latest version of nginx
  apt:
    name: nginx
    state: latest

Instead of:

- name: Install the latest version of nginx (BAD PRACTICE)
  shell: apt-get update && apt-get install -y nginx

2. Not Using Ansible Vault for Secrets

The Mistake: Storing sensitive information, such as passwords, API keys, and certificates, directly in playbooks or variables files.

Why it’s bad:

  • Security Risk: Exposes sensitive data to anyone with access to the repository or files.
  • Compliance Violations: Violates security best practices and industry regulations.

How to avoid it:

  • Employ Ansible Vault: Encrypt sensitive data using Ansible Vault and store the encrypted files in your repository. Decrypt the data at runtime using a password or key.
ansible-vault encrypt secrets.yml
ansible-vault decrypt secrets.yml
ansible-vault edit secrets.yml
  • Reference Vault Variables in Playbooks:
- name: Deploy application with sensitive configuration
  template:
    src: app_config.j2
    dest: /opt/app/config.ini
  vars:
    db_password: ""
  • Pass Vault Password at Runtime: Use --ask-vault-pass or --vault-id when running playbooks that use Vault.
ansible-playbook deploy.yml --ask-vault-pass
ansible-playbook deploy.yml --vault-id @vault_password_file.txt

3. Creating Overly Complex Playbooks

The Mistake: Writing excessively long and complicated playbooks that are difficult to understand, debug, and maintain.

Why it’s bad:

  • Reduced Readability: Makes it hard to grasp the overall purpose and logic of the playbook.
  • Increased Debugging Time: Troubleshooting becomes significantly more challenging.
  • Higher Maintenance Costs: Modifying and updating complex playbooks is time-consuming and error-prone.

How to avoid it:

  • Break Down Playbooks into Roles: Organize your code into reusable roles based on functionality (e.g., webserver, database, monitoring). Roles promote modularity and reusability.
  • Use Include Statements: Divide large playbooks into smaller, more manageable files using include_tasks and include_role.
  • Keep Tasks Concise: Focus each task on a single, well-defined action.
  • Leverage Handlers: Use handlers for tasks that only need to run when a specific event occurs (e.g., restarting a service after a configuration change).
  • Comment your code: Document your playbooks so that other users can better understand their purpose.

4. Ignoring Idempotency

The Mistake: Failing to ensure that your Ansible tasks are idempotent, meaning they only make changes when necessary.

Why it’s bad:

  • Unnecessary Changes: Running the same playbook repeatedly might lead to unintended changes to your infrastructure.
  • Increased Resource Consumption: Wastes CPU, memory, and network resources.
  • Potential Errors: Non-idempotent tasks can introduce unexpected errors and inconsistencies.

How to avoid it:

  • Use the changed_when Conditional: Explicitly define when a task should be considered as having made a change.
- name: Copy configuration file
  copy:
    src: myapp.conf
    dest: /etc/myapp.conf
  notify: restart myapp
  changed_when: "'myapp.conf' not in ansible_facts.files['/etc/myapp.conf'].path"
  • Leverage Modules with Built-in Idempotency: Many Ansible modules, like apt, yum, file, and user, are designed to be idempotent by default.
  • Test your Playbooks: Run your playbooks multiple times to verify that they only make changes when necessary.

5. Neglecting Error Handling

The Mistake: Not implementing proper error handling in your playbooks, leading to failures and unexpected behavior.

Why it’s bad:

  • Playbook Failures: A single task failure can halt the entire playbook execution.
  • Inconsistent State: Leaves your infrastructure in an inconsistent state.
  • Difficult Troubleshooting: Makes it harder to diagnose and resolve issues.

How to avoid it:

  • Use ignore_errors: yes (with Caution): Allows a playbook to continue even if a task fails. Use this sparingly and only when you’re confident that the failure won’t compromise the overall outcome.
  • Implement Rescue Blocks: Define rescue blocks to execute alternative tasks when a task fails. This allows you to gracefully handle errors and attempt to recover.
  • Use block and rescue:
- block:
  - name: Attempt to install a package
    apt:
      name: some-package
      state: present
  rescue:
  - name: Handle package installation failure
    debug:
      msg: "Failed to install some-package.  Continuing with other tasks."
    #Potentially implement a logging step to indicate failure
  always:
  - name: This runs no matter what
    debug:
      msg: "This task always executes"
  • Register Results and Use Conditionals: Register the output of a task and use conditionals (when) to handle errors based on the result.

By avoiding these common mistakes, you can write more robust, maintainable, and secure Ansible playbooks, enabling you to automate your infrastructure with confidence. Remember to always prioritize readability, idempotency, and security in your automation efforts.

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