apptainer-build

Build a container from a definition file

$ apptainer build [path/to/image.sif] [path/to/definition.def]

$ apptainer build [path/to/image.sif] docker://[image]:[tag]

$ apptainer build [path/to/image.sif] library://[user/collection/container]:[tag]

$ apptainer build -s [path/to/directory] docker://[image]:[tag]

$ apptainer build --disable-cache [path/to/image.sif] docker://[image]:[tag]

$ apptainer build -F [path/to/image.sif] [path/to/definition.def]

$ apptainer build -f [path/to/image.sif] [path/to/definition.def]

apptainer build [options] image build-spec

apptainer build creates Apptainer container images from various sources including definition files, Docker Hub, OCI registries, and the Sylabs Container Library. The resulting SIF (Singularity Image Format) file is a portable, immutable container image.
Definition files (.def) provide a reproducible way to specify base images, software installation steps, environment variables, and runscripts. The sandbox mode creates a writable directory structure useful for development and testing.

-s, --sandbox

Build a writable directory instead of an immutable SIF image

Overwrite an existing image file without prompting

Build using fakeroot for unprivileged container builds

Do not use cached images during the build process

Do not clean up the build environment on failure

Run the %post script on an existing sandbox container

/etc/apptainer/apptainer.conf

Main configuration file controlling build behavior, security settings, bind paths, and fakeroot mappings.

Building containers often requires elevated privileges or fakeroot configuration. Some base images may not be compatible with fakeroot builds. Large builds can consume significant disk space in the cache directory.

apptainer(1), apptainer-pull(1), docker(1)