Firecracker vs OpenNebula

Firecracker is open-source virtualization software for running container and function workloads in lightweight microVMs. It uses Linux KVM hardware virtualization to isolate each workload and exposes only five emulated devices, a design intended to reduce attack surface. MicroVMs start in under 125 ms, add under 5 MiB of memory overhead each, and a host can create up to 150 per second while packing thousands onto one server. A RESTful API configures and starts the VMs, while rate limiters govern network and storage bandwidth and operations. The companion jailer adds Linux user-space security barriers. Firecracker supports Linux hosts and guests with kernel versions 4.14 and above, plus OSv guests, on production 64-bit Intel, AMD, and Arm CPUs with hardware virtualization. VM snapshots are supported, but GPU acceleration is not. It is free under Apache 2.0, with integrations including containerd, Kata Containers, and Fly.io.

OpenNebula is an open-source cloud and virtualization management platform for infrastructure across on-premises, public-cloud, and edge environments. Its control plane brings KVM virtual machines and Kubernetes clusters together, and it also supports LXC container virtualization. High-availability features include redundant control-plane components, hypervisor-node failover, and VM replication and recovery workflows across data centers. Management options include a web GUI, command-line tools, and REST, gRPC, and XML-RPC APIs. OpenNebula runs on major Linux distributions including RHEL, Ubuntu, Debian, and AlmaLinux. GPU scheduling with vGPU and MIG supports AI and HPC workloads. The maker lists integrations such as NVIDIA Spectrum-X, SUSE, NetApp, Veeam, and Everpure, as well as certified hosted-cloud providers. The Community Edition is free, while certain tested and certified enterprise releases are subscriber-only. Enterprise subscriptions include unlimited CPUs, cores, and VMs; Standard support is 9×5 and Premium support is 24×7 in CET and EST. Subscription pricing is by tailored proposal, with no price stated.