BuildKit vs Kaniko: Which for Building Images in CI?
BuildKit is the fast, cache-rich default builder; Kaniko builds images without a daemon, which fits locked-down Kubernetes runners.
BuildKit is Docker’s modern build engine, with advanced caching and parallelism. Kaniko builds container images from a Dockerfile inside a container or Kubernetes pod without a Docker daemon or privileged access.
| BuildKit | Kaniko | |
|---|---|---|
| Daemon required | Yes (buildkitd) | No |
| Privileged access | Often needed | Not required |
| Caching | Advanced (local/registry/inline) | Layer cache to registry |
| Speed | Generally faster | Good, fewer features |
| Best fit | General CI, Docker builds | Kubernetes / unprivileged runners |
In CI
BuildKit is usually the faster, more capable builder thanks to advanced caching (registry, inline, mount caches) and parallel build stages - ideal on general CI runners. Kaniko’s advantage is building without a daemon or privileged mode, which suits restricted Kubernetes-based runners where running dockerd is undesirable. Both can push layer cache to a registry to speed repeat builds.
Choosing for pipelines
Prefer BuildKit (via docker buildx) for speed and caching on standard runners. Reach for Kaniko when your runners are unprivileged or Kubernetes-native and you cannot run a build daemon. Configure registry-backed layer caching either way.
The verdict
Standard runners wanting top speed and caching: BuildKit. Unprivileged or Kubernetes runners that cannot run a daemon: Kaniko. Cache layers to a registry on both to avoid rebuilds.