NAME

       apptainer-build - Build an Apptainer image

SYNOPSIS

       apptainer build [local options...]

DESCRIPTION

       IMAGE PATH:

       When Apptainer builds the container, output can be one of a few formats:

         default:    The compressed Apptainer read only image format (default)
         sandbox:    This is a read-write container within a directory structure

       note: It is a common workflow to use the "sandbox" mode for development of the
         container, and then build it as a default Apptainer image for production
         use. The default format is immutable.

       BUILD SPEC:

       The build spec target is a definition (def) file, local image, or URI that can
         be used to create an Apptainer container. Several different local target
         formats exist:

         def file  : This is a recipe for building a container (examples below)
         directory:  A directory structure containing a (ch)root file system
         image:      A local image on your machine (will convert to sif if
                     it is legacy format)

       Targets can also be remote and defined by a URI of the following formats:

         library://  an image library (no default)
         docker://   a Docker/OCI registry (default Docker Hub)
         shub://     an Apptainer registry (default Singularity Hub)
         oras://     an OCI registry that holds SIF files using ORAS

       Temporary files:

       The location used for temporary directories defaults to '/tmp' but
         can be overridden by the TMPDIR environment variable, and that can be
         overridden by the APPTAINER_TMPDIR environment variable.  The
         temporary directory used during a build must be on a filesystem that
         has enough space to hold the entire container image, uncompressed,
         including any temporary files that are created and later removed
         during the build. You may need to set APPTAINER_TMPDIR or TMPDIR when
         building a large container on a system that has a small /tmp filesystem.

OPTIONS

       --arch="amd64"      architecture to build for

       --arch-variant=""      architecture variant to build for

       --authfile=""      Docker-style authentication file to use for writing/reading OCI registry credentials

       -B,  --bind=[]       a  user-bind path specification. spec has the format src[:dest[:opts]],where src and
       dest are outside and inside paths. If dest is not given,it is set equal to src.  Mount  options  ('opts')
       may be specified as 'ro'(read-only) or 'rw' (read/write, which is the default).Multiple bind paths can be
       given by a comma separated list.

       --build-arg=[]      defines variable=value to replace {{ variable }} entries in build definition file

       --build-arg-file=""       specifies  a  file  containing variable=value lines to replace '{{ variable }}'
       with value in build definition files

       --disable-cache[=false]      do not use cache or create cache

       --docker-host=""      specify a custom Docker daemon host

       --docker-login[=false]      login to a Docker Repository interactively

       -e, --encrypt[=false]      build an image with an encrypted file system

       -f, --fakeroot[=false]      build with the appearance of running as root (default when  building  from  a
       definition file unprivileged)

       --fix-perms[=false]      ensure owner has rwX permissions on all container content for oci/docker sources

       -F, --force[=false]      overwrite an image file if it exists

       -h, --help[=false]      help for build

       --json[=false]      interpret build definition as JSON

       --library=""      container Library URL

       --mksquashfs-args=""      extra arguments to pass to mksquashfs when creating SIF files

       --mount=[]      a mount specification e.g. 'type=bind,source=/opt,destination=/hostopt'.

       --no-cleanup[=false]      do NOT clean up bundle after failed build, can be helpful for debugging

       --no-https[=false]      use http instead of https for docker:// oras:// and library:///... URIs

       -T, --notest[=false]      build without running tests in %test section

       --nv[=false]      inject host Nvidia libraries during build for post and test sections

       --nvccli[=false]      use nvidia-container-cli for GPU setup (experimental)

       --passphrase[=false]      prompt for an encryption passphrase

       --pem-path=""      enter an path to a PEM formatted RSA key for an encrypted container

       --rocm[=false]      inject host Rocm libraries during build for post and test sections

       -s, --sandbox[=false]      build image as sandbox format (chroot directory structure)

       --section=[all]       only  run  specific  section(s)  of deffile (setup, post, files, environment, test,
       labels, none)

       -u, --update[=false]      run definition over existing container (skips header)

       --userns[=false]      build without using setuid even if available

       --warn-unused-build-args[=false]      shows warning instead of fatal message  when  build  args  are  not
       exact matched

       --writable-tmpfs[=false]       during  the  %test section, makes the file system accessible as read-write
       with non persistent data (with overlay support only)

EXAMPLE

         DEF FILE BASE OS:

             Library:
                 Bootstrap: library
                 From: debian:9

             Docker:
                 Bootstrap: docker
                 From: tensorflow/tensorflow:latest
                 IncludeCmd: yes # Use the CMD as runscript instead of ENTRYPOINT

             Singularity Hub:
                 Bootstrap: shub
                 From: singularityhub/centos

             YUM/RHEL:
                 Bootstrap: yum
                 OSVersion: 7
                 MirrorURL: http://mirror.centos.org/centos-%{OSVERSION}/%{OSVERSION}/os/x86_64/
                 Include: yum

             SUSE:
                 Bootstrap: zypper # on SLE system registration of build host is used
                 Include: zypper

             openSUSE:
                 Bootstrap: zypper
                 MirrorURL: http://download.opensuse.org/distribution/openSUSE-stable/repo/oss
                 Include: zypper

             Debian/Ubuntu:
                 Bootstrap: debootstrap
                 OSVersion: trusty
                 MirrorURL: http://us.archive.ubuntu.com/ubuntu/

             Local Image:
                 Bootstrap: localimage
                 From: /home/dave/starter.img

             Scratch:
                 Bootstrap: scratch # Populate the container with a minimal rootfs in %setup

         DEFFILE SECTIONS:

         The following sections are presented in the order of processing, with the exception
         that labels and environment can also be manipulated in %post.

             %pre
                 echo "This is a scriptlet that will be executed on the host, as root before"
                 echo "the container has been bootstrapped. This section is not commonly used."

             %setup
                 echo "This is a scriptlet that will be executed on the host, as root, after"
                 echo "the container has been bootstrapped. To install things into the container"
                 echo "reference the file system location with $APPTAINER_ROOTFS."

             %files
                 /path/on/host/file.txt /path/on/container/file.txt
                 relative_file.txt /path/on/container/relative_file.txt

             %post
                 echo "This scriptlet section will be executed from within the container after"
                 echo "the bootstrap/base has been created and setup."

             %environment
                 LUKE=goodguy
                 VADER=badguy
                 HAN=someguy
                 export HAN VADER LUKE

             %test
                 echo "Define any test commands that should be executed after container has been"
                 echo "built. This scriptlet will be executed from within the running container"
                 echo "as the root user. Pay attention to the exit/return value of this scriptlet"
                 echo "as any non-zero exit code will be assumed as failure."
                 exit 0

             %runscript
                 echo "Define actions for the container to be executed with the run command or"
                 echo "when container is executed."

             %startscript
                 echo "Define actions for container to perform when started as an instance."

             %labels
                 HELLO MOTO
                 KEY VALUE

             %help
                 This is a text file to be displayed with the run-help command.

         COMMANDS:

             Build a sif file from an Apptainer recipe file:
                 $ apptainer build /tmp/debian0.sif /path/to/debian.def

             Build a sif image from the Library:
                 $ apptainer build /tmp/debian1.sif library://debian:latest

             Build a base sandbox from DockerHub, make changes to it, then build sif
                 $ apptainer build --sandbox /tmp/debian docker://debian:latest
                 $ apptainer exec --writable /tmp/debian apt-get install python
                 $ apptainer build /tmp/debian2.sif /tmp/debian

SEE ALSO

       apptainer(1)

HISTORY

       21-Jul-2025 Auto generated by spf13/cobra

Auto generated by spf13/cobra                       Jul 2025                                        apptainer(1)