Buildah vs gVisor

Buildah is a free command-line tool for building OCI container images on Linux. It can create images from working containers, Dockerfiles, or Containerfiles, and can also build through commands and scripts without a build file. Output can use OCI format or the traditional upstream Docker image format. Builds can run without root privileges, and Buildah follows a fork-exec model rather than running as a daemon. Its commands create, mount, unmount, delete, and rename working containers, as well as create or delete images; users can also pull images from a specified location and push local images elsewhere. Buildah is based on a Go API that other tools can vendor, and Podman uses it for Dockerfile builds while remaining independently installable. Buildah requires a kernel with OverlayFS or fuse-overlayfs support; RHEL or CentOS requires version 7.4 or later. Installation guidance warns that short image names can be spoofed and recommends fully qualified names from trusted registries or pulling by digest. The project points users to tutorials, releases, and a mailing list for questions.

gVisor is a free, open-source Linux-compatible sandbox and application kernel for running containers while isolating the host from untrusted code. It is intended for workloads such as user-uploaded, LLM-generated, and third-party code. Instead of passing sandboxed applications’ system calls directly to the host, its Sentry handles them; a Gofer process mediates filesystem access. The project describes a least-privilege design with a restrictive system call filter. It documents use with Docker, Kubernetes, containerd, and OCI runtimes, including Kubernetes configurations using GKE Sandbox, Minikube, or containerd with the gVisor shim. gVisor can stream application trace points to an external threat detection engine such as Falco, and can checkpoint and restore containers. Most CUDA applications can run unmodified in the sandbox with selected NVIDIA driver versions, but GPU support is restricted to certain models, drivers, capabilities, device files, ioctl calls, and platforms. Installation requires Linux 5.6 or later on x86_64 or ARM64. Compatibility is best-effort, and some applications may not work because not every system call, /proc file, or /sys file is implemented. Hardware side-channel protection is generally not provided.