How a VM is Created in OpenStack: From Heat to Swift

OpenStack has become one of the most widely adopted cloud platforms for telecom and IT environments. It provides a modular architecture where different services work together to manage the entire lifecycle of a virtual machine (VM). Let’s walk through the process of creating and managing a VM, step by step.

1. Heat and Horizon – The Entry Point

Users can start a VM deployment through Horizon, the OpenStack dashboard, or through Heat, the orchestration engine.

• Horizon provides a graphical interface for launching and managing instances.

• Heat enables automated deployments using templates, making it easier to scale and replicate environments.

Both pass the deployment request into the core OpenStack services.

2. Nova – The Compute Service

At the heart of VM creation is Nova, the compute service. Nova receives the request and is responsible for scheduling the VM to a suitable compute host. It communicates with other services to gather all the necessary resources before launching the instance.

3. Glance – Image Service

Every VM needs an operating system image. Glance stores and manages these images. When a new VM is created, Nova fetches the chosen image from Glance to boot the virtual machine.

4. Neutron – Networking Service

To connect the VM to the network, Neutron provides virtual networks, subnets, routers, and security groups. It ensures the VM gets the right IP address and connectivity to other VMs or external networks.

5. Cinder – Block Storage

If the VM requires persistent storage, Cinder provisions virtual block volumes. These volumes can be attached to the VM just like a physical hard drive, ensuring data persists even after the VM is rebooted.

6. Running the VM

Once compute, image, network, and storage resources are provisioned, Nova launches the VM. At this point, the user has a running instance, accessible through the network configured by Neutron.

7. Creating and Storing Images with Swift

Users can generate a custom VM image (for example, after installing applications). This image can be uploaded back to Glance for reuse. For long-term storage, Swift, the object storage service, can be used to archive VM images and snapshots efficiently.

Conclusion

The process of creating a VM in OpenStack is a coordinated effort across multiple services: Heat/Horizon → Nova → Glance → Neutron → Cinder → Swift. This modular design is what makes OpenStack powerful — each service handles a specific function, and together they deliver a flexible, scalable cloud platform for telecom and enterprise workloads.