Ubuntu Manpage: buildah-commit - Create an image from a working container.

NAME

       buildah-commit - Create an image from a working container.

SYNOPSIS

       buildah commit [options] container [image]

DESCRIPTION

       Writes  a new image using the specified container's read-write layer and if it is based on
       an image, the layers of that image.   If  image  does  not  begin  with  a  registry  name
       component,  localhost will be added to the name.  If image is not provided, the image will
       have no name.  When an image has no name, the buildah images command will  display  <none>
       in the REPOSITORY and TAG columns.

RETURN VALUE

       The  image  ID  of  the  image  that  was  created.   On error, 1 is returned and errno is
       returned.

OPTIONS

--authfile path

Path of the authentication file. Default is ${XDG_\RUNTIME_DIR}/containers/auth.json. If
XDG_RUNTIME_DIR is not set, the default is /run/containers/$UID/auth.json. This file is
created using buildah login.

If the authorization state is not found there, $HOME/.docker/config.json is checked, which
is set using docker login.

Note: You can also override the default path of the authentication file by setting the
REGISTRY_AUTH_FILE environment variable. export REGISTRY_AUTH_FILE=path

--cert-dir path

Use certificates at path (*.crt, *.cert, *.key) to connect to the registry. The default
certificates directory is /etc/containers/certs.d.

--change, -c "INSTRUCTION"

Apply the change to the committed image that would have been made if it had been built
using a Containerfile which included the specified instruction. This option can be
specified multiple times.

--config filename

Read a JSON-encoded version of an image configuration object from the specified file, and
merge the values from it with the configuration of the image being committed.

--creds creds

The [username[:password]] to use to authenticate with the registry if required. If one or
both values are not supplied, a command line prompt will appear and the value can be
entered. The password is entered without echo.

--cw options

Produce an image suitable for use as a confidential workload running in a trusted
execution environment (TEE) using krun (i.e., crun built with the libkrun feature enabled
and invoked as krun). Instead of the conventional contents, the root filesystem of the
image will contain an encrypted disk image and configuration information for krun.

The value for options is a comma-separated list of key=value pairs, supplying
configuration information which is needed for producing the additional data which will be
included in the container image.

Recognized keys are:

attestation_url: The location of a key broker / attestation server. If a value is
specified, the new image's workload ID, along with the passphrase used to encrypt the disk
image, will be registered with the server, and the server's location will be stored in the
container image. At run-time, krun is expected to contact the server to retrieve the
passphrase using the workload ID, which is also stored in the container image. If no
value is specified, a passphrase value must be specified.

cpus: The number of virtual CPUs which the image expects to be run with at run-time. If
not specified, a default value will be supplied.

firmware_library: The location of the libkrunfw-sev shared library. If not specified,
buildah checks for its presence in a number of hard-coded locations.

memory: The amount of memory which the image expects to be run with at run-time, as a
number of megabytes. If not specified, a default value will be supplied.

passphrase: The passphrase to use to encrypt the disk image which will be included in the
container image. If no value is specified, but an attestation_url value is specified, a
randomly-generated passphrase will be used. The authors recommend setting an
attestation_url but not a passphrase.

slop: Extra space to allocate for the disk image compared to the size of the container
image's contents, expressed either as a percentage (..%) or a size value (bytes, or larger
units if suffixes like KB or MB are present), or a sum of two or more such specifications
separated by "+". If not specified, buildah guesses that 25% more space than the contents
will be enough, but this option is provided in case its guess is wrong. If the specified
or computed size is less than 10 megabytes, it will be increased to 10 megabytes.

type: The type of trusted execution environment (TEE) which the image should be marked for
use with. Accepted values are "SEV" (AMD Secure Encrypted Virtualization - Encrypted
State) and "SNP" (AMD Secure Encrypted Virtualization - Secure Nested Paging). If not
specified, defaults to "SNP".

workload_id: A workload identifier which will be recorded in the container image, to be
used at run-time for retrieving the passphrase which was used to encrypt the disk image.
If not specified, a semi-random value will be derived from the base image's image ID.

--disable-compression, -D

Don't compress filesystem layers when building the image unless it is required by the
location where the image is being written. This is the default setting, because image
layers are compressed automatically when they are pushed to registries, and images being
written to local storage would only need to be decompressed again to be stored.
Compression can be forced in all cases by specifying --disable-compression=false.

--encrypt-layer layer(s)

Layer(s) to encrypt: 0-indexed layer indices with support for negative indexing (e.g. 0 is
the first layer, -1 is the last layer). If not defined, will encrypt all layers if
encryption-key flag is specified.

--encryption-key key

The [protocol:keyfile] specifies the encryption protocol, which can be JWE (RFC7516), PGP
(RFC4880), and PKCS7 (RFC2315) and the key material required for image encryption. For
instance, jwe:/path/to/key.pem or pgp:admin@example.com or pkcs7:/path/to/x509-file.

--format, -f [oci | docker]

Control the format for the image manifest and configuration data. Recognized formats
include oci (OCI image-spec v1.0, the default) and docker (version 2, using schema format
2 for the manifest).

Note: You can also override the default format by setting the BUILDAH_FORMAT environment
variable. export BUILDAH\_FORMAT=docker

--identity-label bool-value

Adds default identity label io.buildah.version if set. (default true).

--iidfile ImageIDfile

Write the image ID to the file.

--manifest "listName"

Name of the manifest list to which the built image will be added. Creates the manifest
list if it does not exist. This option is useful for building multi architecture images.

--omit-history bool-value

Omit build history information in the built image. (default false).

This option is useful for the cases where end users explicitly want to set --omit-history
to omit the optional History from built images or when working with images built using
build tools that do not include History information in their images.

--quiet, -q

When writing the output image, suppress progress output.

--rm Remove the working container and its contents after creating the image. Default
leaves the container and its content in place.

--sign-by fingerprint

Sign the new image using the GPG key that matches the specified fingerprint.

--squash

Squash all of the new image's layers (including those inherited from a base image) into a
single new layer.

--timestamp seconds

Set the create timestamp to seconds since epoch to allow for deterministic builds
(defaults to current time). By default, the created timestamp is changed and written into
the image manifest with every commit, causing the image's sha256 hash to be different even
if the sources are exactly the same otherwise. When --timestamp is set, the created
timestamp is always set to the time specified and therefore not changed, allowing the
image's sha256 to remain the same. All files committed to the layers of the image will be
created with the timestamp.

--tls-verify bool-value

Require HTTPS and verification of certificates when talking to container registries
(defaults to true). TLS verification cannot be used when talking to an insecure registry.

--unsetenv env

Unset environment variables from the final image.

EXAMPLE

       This example saves an image based on the container.
        buildah commit containerID newImageName

       This example saves an image named newImageName based on the container.
        buildah commit --rm containerID newImageName

       This example saves an image with no name, removes the working container, and creates a new
       container using the image's ID.
        buildah from $(buildah commit --rm containerID)

       This example saves an image based on the container disabling compression.
        buildah commit --disable-compression containerID

       This  example  saves  an  image  named  newImageName  based  on  the  container  disabling
       compression.
        buildah commit --disable-compression containerID newImageName

       This  example  commits  the container to the image on the local registry while turning off
       tls verification.
        buildah commit --tls-verify=false containerID docker://localhost:5000/imageId

       This example commits the container to the image on the local  registry  using  credentials
       and certificates for authentication.
        buildah commit --cert-dir ~/auth  --tls-verify=true --creds=username:password containerID
       docker://localhost:5000/imageId

       This example commits the container to the image on the local  registry  using  credentials
       from the /tmp/auths/myauths.json file and certificates for authentication.
        buildah  commit  --authfile  /tmp/auths/myauths.json --cert-dir ~/auth  --tls-verify=true
       --creds=username:password containerID docker://localhost:5000/imageName

       This example saves an image based on the container, but stores dates based on epoch  time.
       buildah commit --timestamp=0 containerID newImageName

   Building an multi-architecture image using the --manifest option (requires emulation software)
       #!/bin/sh
       build() {
            ctr=$(./bin/buildah from --arch $1 ubi8)
            ./bin/buildah run $ctr dnf install -y iputils
            ./bin/buildah commit --manifest ubi8ping $ctr
       }
       build arm
       build amd64
       build s390x

ENVIRONMENT

       BUILD_REGISTRY_SOURCES

       BUILD_REGISTRY_SOURCES,  if  set,  is  treated  as  a  JSON object which contains lists of
       registry   names   under   the    keys    insecureRegistries,    blockedRegistries,    and
       allowedRegistries.

       When committing an image, if the image is to be given a name, the portion of the name that
       corresponds to a registry is compared to the items in the blockedRegistries list,  and  if
       it  matches  any  of  them,  the commit attempt is denied.  If there are registries in the
       allowedRegistries list, and the portion of the name that corresponds to  the  registry  is
       not in the list, the commit attempt is denied.

       TMPDIR  The  TMPDIR  environment variable allows the user to specify where temporary files
       are stored while pulling and pushing images.  Defaults to '/var/tmp'.

FILES

       registries.conf (/etc/containers/registries.conf)

       registries.conf is the configuration  file  which  specifies  which  container  registries
       should  be consulted when completing image names which do not include a registry or domain
       portion.

       policy.json (/etc/containers/policy.json)

       Signature policy file.  This defines the trust  policy  for  container  images.   Controls
       which container registries can be used for image, and whether or not the tool should trust
       the images.