🗂️ Xloud XAVS – Glance Image Service & Custom Image Storage Configuration

1. 🔎 Introduction

Xloud XAVS OpenStack includes a fully integrated Glance Image Service, which enables users to discover, upload, and manage virtual machine images used across the platform. Glance serves as the centralized repository for VM images and plays a vital role in compute provisioning by supplying images to Nova during instance creation.

The Glance service is designed to support a variety of backend storage options, ensuring flexibility and scalability for diverse customer environments.

2. 🧱 Architecture Overview

🔹 Image Service Architecture

Users upload images via Horizon UI, OpenStack CLI, or API.
Glance stores image data using the selected backend (e.g., local FS, Swift, Ceph, etc.).
Nova retrieves images from Glance when provisioning new VMs.
Glance APIs manage image metadata, formats, versioning, and access policies.
Multiple backends can be configured simultaneously and selected per image.

3. ✨ Supported Storage Backends

Backend Type	Description
Local File System	Stores image files on the Glance host's disk. Ideal for simple deployments.
Object Storage (Swift)	Uses OpenStack Swift for scalable and distributed image storage.
Ceph RBD	Stores images in Ceph's RADOS Block Device; supports native sharing across services.
Amazon S3	S3-compatible support exists but is deprecated in most production cases.
VMware Datastore	Allows storing images directly in vSphere environments (for VMware integration).

📌 Xloud XAVS can operate multiple backends concurrently and assign them dynamically per image upload.

4. 🧰 Use Case: Custom Local Directory for Image Storage

In some deployments, administrators may want to store image files in a custom local directory (e.g., on dedicated volumes or bind-mounted storage). Xloud XAVS supports this through configuration overrides.

✅ Example: Configure a Custom Directory

Create Override Configuration Path On the control node:
```
mkdir -p /etc/xavs/config/glance
```

Define the Custom Image Path Example override snippet:

[glance_store]
default_backend = file
filesystem_store_datadir = /mnt/glance_images/

Prepare the Host Storage Path
```
sudo mkdir -p /mnt/glance_images/
sudo chown 42424:42424 /mnt/glance_images/
```
- 42424 is the default UID/GID for Glance in Xloud XAVS (adjust if needed).
Apply the Configuration Deploy configuration changes with:
```
xavs reconfigure -t glance
```

5. 🤖 Automation and Operational Fit

Terraform-Compatible: Glance image upload actions can be embedded in Terraform workflows.
Ansible Integration: Image uploads and directory permissions can be managed via Ansible tasks.
Multi-Store Support: Admins can register multiple backends and select which one to use per image.
Secure Access Control: Role-based visibility and image access policies applied at the project/tenant level.

6. ✅ Summary & Positioning

The Xloud XAVS Glance Image Service provides robust and flexible image management for virtual machine provisioning. With multi-backend support and customizable local directory storage, Glance ensures:

Consistent image availability across compute nodes
Scalable image distribution and replication
Seamless integration with object storage, Ceph, or local disks
Secure, tenant-aware image operations

🟢 Customer Experience: Upload your images via UI, CLI, or API—our platform manages where and how they are stored based on your configuration or policy.

Integration with external directory External DNS Providers