Firecracker vs oVirt

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.

oVirt is a free, open-source distributed virtualization system for managing enterprise infrastructure. It uses the KVM hypervisor and builds on community projects including libvirt, Gluster, PatternFly, and Ansible. Deployment options include a self-hosted Engine and a standalone Engine; the project recommends the self-hosted option, which runs as a virtual machine on specialized hosts and is highly available without external HA management. Centralized storage holds virtual machine disks, ISO files, and snapshots, with options including NFS, GlusterFS, iSCSI, local storage, Fibre Channel, pNFS, and other POSIX-compliant filesystems. Automation and integration are available through Ansible roles and collections, Python, Java, and Ruby SDKs, and a REST API. The download page identifies version 4.5.7 as intended for production use, with Engine and host support for Enterprise Linux 9 or 10 and CentOS Stream 9 or 10. Installation is by command line. At least one additional host is required for advanced features such as migration and high availability. The project points users to community forums, IRC, and Matrix, and invites contributions.