Error Notifications in Ansible

Introduction

In an automation context, dealing with errors effectively is crucial for maintaining robust systems. Ansible, a powerful IT automation tool, provides several mechanisms for handling errors. One of the most useful features is error notifications, which allows users to be promptly informed about issues that arise during playbook execution.

Understanding Error Notifications

Error notifications in Ansible are typically handled using the "notify" and "handlers" mechanisms. This allows you to define actions that should only be performed when a task fails. Notifications can be used to alert administrators, roll back changes, or trigger other remediation actions.

Setting Up a Basic Error Notification

Let's start with a simple example. Suppose we have a task that might fail, and we want to send an email notification if it does. Below is a basic playbook that demonstrates this.

---
- name: Example playbook with error notification
  hosts: localhost
  tasks:
    - name: Deliberately fail this task
      command: /bin/false
      ignore_errors: yes
      register: result
      notify: Send failure notification

  handlers:
    - name: Send failure notification
      debug:
        msg: "Task failed with the following error: {{ result }}"
                

In this example:

• The command: /bin/false task is deliberately made to fail.
• The ignore_errors: yes directive is used to prevent the playbook from stopping.
• The register: result directive stores the result of the command.
• The notify: Send failure notification directive triggers the handler if the task fails.
• The handler Send failure notification simply prints a debug message with the error details.

Advanced Error Notification: Sending an Email

For a more practical scenario, you might want to send an email notification when a task fails. This can be achieved using the mail module. Below is an example playbook:

---
- name: Playbook with email notification on failure
  hosts: localhost
  tasks:
    - name: Run a task that might fail
      command: /bin/false
      ignore_errors: yes
      register: result
      notify: Send failure email

  handlers:
    - name: Send failure email
      mail:
        host: smtp.example.com
        port: 25
        to: admin@example.com
        from: ansible@example.com
        subject: "Ansible Task Failed"
        body: "The following task has failed: {{ result }}"
                

In this example:

• The mail module is used to send an email containing the error details.
• The email is configured with SMTP server details, recipient address, sender address, subject, and body.
• The body of the email includes the error details stored in the result variable.

Using Conditional Handlers

Sometimes, you may want to conditionally execute handlers based on certain criteria. Ansible allows you to add conditions to handlers using the when directive. Here is an example:

---
- name: Conditional handler example
  hosts: localhost
  tasks:
    - name: Run a task that might fail
      command: /bin/false
      ignore_errors: yes
      register: result
      notify: Conditionally send email

  handlers:
    - name: Conditionally send email
      mail:
        host: smtp.example.com
        port: 25
        to: admin@example.com
        from: ansible@example.com
        subject: "Ansible Task Failed"
        body: "The following task has failed: {{ result }}"
      when: result.failed
                

In this example:

• The handler Conditionally send email is only triggered if the task fails, as specified by the when: result.failed condition.

Conclusion

Error notifications are a powerful feature in Ansible that can help you quickly identify and respond to issues in your automation processes. By using the "notify" and "handlers" mechanisms, you can create robust playbooks that not only handle errors gracefully but also keep you informed about any problems that arise.