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Modern Storage Automation: Scaling Volumes with Ansible & REST APIs

By Imran Shaik posted 07-14-2025 12:09

Modern Storage Automation: Scaling Volumes with Ansible & REST APIs

Introduction

In the modern enterprise storage landscape, capacity management is a critical operational task. As storage volumes grow and application demands shift dynamically, manual monitoring and management of volume utilization becomes both time-consuming and error prone.

Solution Overview

To address the challenges of manual storage volume management, we designed and implemented an automated solution using Ansible that interacts with the Hitachi VSP storage subsystem via REST APIs.

Here are the key components and capabilities of the solution:

Scheduled Automation:

The playbook runs every 6 hours via a cron job (Linux) or Task Scheduler (Windows).

No manual intervention is required.

Dynamic Volume Monitoring:

The playbook connects to the Hitachi VSP array using secure REST APIs.

It retrieves the latest information about all logical devices (volumes), including:

Total Size

Used Size

Utilization %

Threshold-Based Filtering:

Volumes with >85% utilization are automatically flagged for action.

The threshold can be fine-tuned via configuration.

Automated Volume Expansion:

Based on utilization level and policy, volumes are expanded by:

10% (significant breach, rapid correction)

The playbook ensures idempotency — it will not expand to the same volume multiple times unnecessarily.

End-User Notification:

After each run, a clean, human-readable email report is sent to stakeholders.

Benefits of This Architecture:

Proactive capacity management prevents incidents.
Zero touch — reduces admin effort.
Consistent, repeatable actions via automation.
Better communication with stakeholders (email report).
Enterprise ready — scalable, configurable, extensible.

Detailed Overview:

The automation solution follows a clearly defined, repeatable workflow:

Scheduled Execution

A cron job (Linux) or Task Scheduler (Windows) triggers the Ansible playbook every 6 hours.

This ensures timely and consistent monitoring of volume utilization without manual effort.

Secure Connection to Hitachi VSP

The playbook establishes a connection to the Hitachi VSP storage subsystem using the Hitachi REST API.

Connection parameters (IP, username, password) are securely stored in an Ansible Vault to ensure best practices in credential management.

Retrieval of Volume Data

The playbook invokes the Hitachi API to retrieve the latest logical device facts, including:

Volume Name / LDEV ID

Total Provisioned Size

Used Size / Capacity

Utilization Percentage (%)

The data is structured into a list of volumes for easy processing in the next steps.

Identification of High Utilization Volumes

The playbook applies a filtering step:

It selects volumes where Utilization %> 85%.

This threshold is configurable and can be adapted for different environments (e.g., dev vs prod).

This step ensures that only the volumes at risk of running out of space are targeted for expansion.

Calculation of Target Size

For each high-utilization volume, the playbook calculates the new target size:

If the user has selected a 10% policy, the new size = Current Size * 1.10.

This flexible logic allows controlled, incremental expansion, or rapid correction as needed.

Volume Expansion

Using the appropriate Hitachi volume expansion API, the playbook triggers a controlled volume size increase.

Care is taken to ensure idempotent execution:

If a volume was already expanded in a previous run and is now below threshold, it is skipped.

If expansion fails due to storage system constraints, the failure is logged and included in the report.

Reporting & Notification

Once volume expansion is complete, the playbook generates a detailed email report.

The email contains the following for each affected volume:

Volume Name

LDEV ID

Previous Size (GB)

New Size (GB)

% Increase Applied

Timestamp of Action

The email is sent to a predefined recipient list — typically storage admins, capacity planners, and key application owners.

Summary

Ansible-based automation that connects to Hitachi VSP storage systems every 6 hours, monitors all volumes, and automatically expands those exceeding 85% utilization — by 10%, based on policy.

Key capabilities:

Proactive capacity management — avoids volume full incidents.

Policy-driven automation — ensures controlled growth.

Transparent reporting — detailed email sent after each run.

Audit-ready — all actions logged for compliance.

This solution has reduced manual effort, improved SLA adherence, and moved our storage operations toward a truly autonomous, Infrastructure-as-Code model.

You can access the automation script I developed here, designed to enhance operational efficiency and streamline key processes.

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