Charliecloud vs Kata Containers

Charliecloud is free, open-source container software for high-performance computing on Linux. It runs containers without privileged operations or daemons by using Linux user namespaces, with minimal configuration changes on computing-center resources. Users can build images, push and pull them to registries, and use accelerators such as GPUs. Its layer-free build cache is based on Git rather than union-mount filesystems and tarballs, and Dockerfiles are parsed with a formal grammar. The ch-image tool supports registry authentication and registries including GitLab Container Registry. At runtime, ch-run can inject host resources through the Container Device Interface, including NVIDIA GPUs and Cray networking. Installation is available from a release tarball, Git checkout, Spack, or Fedora/EPEL. Charliecloud requires Linux user namespaces and has been run on x86-64, ARM, and Power; current testing covers x86_64 and ARM. It is distributed under Apache License, Version 2.0. The project supports only the current release and provides no internal security boundary.

Kata Containers is a free, open-source Linux container runtime that uses lightweight virtual machines for workload isolation while remaining compatible with the container ecosystem. Each workload runs in a dedicated kernel, separating network, I/O, and memory; hardware virtualization can provide an additional defense layer. The runtime supports OCI container images, the Kubernetes CRI interface, and integrations with Docker and Kubernetes. Supported hypervisors include QEMU, Cloud Hypervisor, and Firecracker. Listed hardware includes Nvidia GPU, FPGA, QAT, RDMA, and SR-IOV, with x86_64, aarch64, ppc64le, and s390x architectures. Kata requires nested virtualization or bare metal, and kata-check can check host capability. Installation guides cover CentOS, Debian, Fedora, OpenSUSE, RHEL, SLES, and Ubuntu. Listed cloud platforms include Amazon Web Services, Microsoft Azure, Google Compute Engine, and Vexxhost OpenStack Cloud. The Apache 2.0 license permits use and distribution. Only the current monthly release series receives security fixes; older releases are unsupported and there are no long-term-support branches.