OpenStack is an open-source platform for building public and private clouds. It turns racks of servers into a self-service IaaS with APIs for VMs, networks, block storage and more, similar to what large cloud providers offer. This guide explains its components and when it is worth the complexity.
Before you start
- Background: public vs private cloud and IaaS.
Core services
| Service | Project | Role |
|---|---|---|
| Identity | Keystone | Users, projects, roles and API tokens |
| Compute | Nova | Schedules and runs VMs, usually on KVM via libvirt |
| Networking | Neutron | Virtual networks, routers, floating IPs, security groups |
| Images | Glance | OS images for new VMs |
| Block storage | Cinder | Volumes attached to VMs, often backed by Ceph |
| Object storage | Swift | S3-like object store (Ceph RGW is a common alternative) |
| Dashboard | Horizon | Web UI for users and admins |
| Orchestration | Heat | Templates for whole stacks |
How it fits together
- Controller nodes run APIs, databases and message queues.
- Compute nodes run KVM and the Nova agent.
- Network nodes (or distributed routing) handle virtual routers and NAT using Open vSwitch or OVN.
- Storage usually comes from a Ceph cluster.
Deployment options
- Kolla-Ansible (containerised services deployed with Ansible).
- OpenStack-Ansible.
- Distribution-backed offerings from several vendors, often with support contracts.
- Single-node test setups such as DevStack or MicroStack for learning only.
OpenStack vs Proxmox vs VPS panels
| OpenStack | Proxmox VE | VPS panel (Virtualizor, VirtFusion) | |
|---|---|---|---|
| Scale | Dozens to thousands of nodes | Single host to medium clusters | Many hypervisors for VPS hosting |
| Multi-tenancy and APIs | Full cloud APIs, projects, quotas | Basic users and pools | Customer panels and billing modules |
| Complexity | High | Low | Low–medium |
| Team needed | Dedicated cloud engineers | Sysadmin | Hosting operator |
See VPS control panels compared.
When OpenStack makes sense
- Large organisations or providers needing cloud-style APIs on their own hardware.
- Strict data sovereignty with many tenants and teams.
- Not for a handful of servers: Proxmox or a VPS panel is far simpler.
Frequently asked questions
Is OpenStack free?
The software is open source; costs come from hardware, staff and optional vendor support.
Does OpenStack only use KVM?
KVM is by far the most common; other drivers exist but see less use.
Can Terraform manage OpenStack?
Yes, there is an official OpenStack provider; see Terraform basics.