Running Linux workloads in a cloud environment often goes beyond simply launching virtual machines. Teams need mechanisms to customize operating systems, automate configuration, and reuse standardized setups across multiple deployments. OpenNebula supports this workflow by combining ready-to-use marketplace images, flexible VM templates, and built-in contextualization features.

Ready-to-Use Linux Images from the OpenNebula Marketplace

OpenNebula distributes Linux OS images through its Public Marketplace, providing preconfigured images that are immediately compatible with the platform. Each marketplace image is bundled with a corresponding VM Template and includes OpenNebula contextualization packages, which enable automated configuration and lifecycle management inside the virtual machine.

These templates can be used directly for VM deployment or serve as a baseline for more specialized workloads. For users building custom images from scratch, the same contextualization packages can be installed manually to ensure full compatibility with OpenNebula’s management features.

Customizing VM Templates and Operating System Configuration

Starting from a marketplace image, users can adapt VM Templates to match workload requirements by adjusting compute resources, attaching networks, and defining contextualization parameters. Context variables allow operators to configure default users, hostname patterns, startup scripts, and other system-level settings that are applied automatically during VM boot. These settings can also be reconfigured and reapplied while the VM is running.

Once instantiated, the virtual machine can be accessed to install additional software, perform operating system tuning, or apply security hardening. These changes are made directly within the guest OS, allowing full control over the resulting system configuration while still leveraging OpenNebula’s orchestration capabilities.

Building and Reusing Golden Images

After customization is complete, the virtual machine’s disk can be exported as a new image, capturing the full state of the operating system. This image can then be substituted into a VM Template—typically a clone of the original—to create a reusable deployment blueprint without modifying the original marketplace assets.

This process enables the creation of golden images: standardized operating system images that embed required software, configuration, and tuning. Golden images can be used to deploy multiple virtual machines consistently, ensuring repeatability across environments while reducing manual configuration and operational overhead.

End-to-End Workflow Demonstration

The accompanying screencast walks through the workflow from importing a Linux OS image from the OpenNebula Marketplace to deploying virtual machines based on a customized golden image. It focuses on how VM templates, contextualization, and image management are applied in practice throughout the process.

Standardizing Linux Workloads at Scale

This workflow is particularly useful for teams that need to maintain consistent Linux environments across multiple deployments while retaining the ability to customize and evolve their operating system images over time. By separating base marketplace assets from customized golden images, OpenNebula enables controlled standardization without limiting flexibility—an important requirement for both development and production environments.