Brian C. Lane <>

composer-cli is an interactive tool for use with a WELDR API server, managing blueprints, exploring available packages, and building new images. As of Fedora 34, osbuild-composer <> is the recommended server.

It requires the server to be installed on the local system, and the user running it needs to be a member of the weldr group.

composer-cli cmdline arguments

Lorax Composer commandline tool

usage: composer-cli [-h] [-j] [-s SOCKET] [--log LOG] [-a APIVER] [--test TESTMODE] [-V] ...

Positional Arguments


Named Arguments

-j, --json

Output the raw JSON response instead of the normal output.

Default: False

-s, --socket

Path to the socket file to listen on

Default: "/run/weldr/api.socket"


Path to logfile (./composer-cli.log)

-a, --api

API Version to use

Default: "1"


Pass test mode to compose. 1=Mock compose with fail. 2=Mock compose with finished.

Default: 0


show program's version number and exit

Default: False


Start a compose using the selected blueprint and output type. Optionally start an upload. --size is supported by osbuild-composer, and is in MiB.

compose start-ostree [--size XXXX] [--parent PARENT] [--ref REF] <BLUEPRINT> <TYPE> [<IMAGE-NAME> <PROFILE.TOML>]

Start an ostree compose using the selected blueprint and output type. Optionally start an upload. This command is only supported by osbuild-composer. --size is in MiB.

compose types

List the supported output types.

compose status

List the status of all running and finished composes.

compose list [waiting|running|finished|failed]

List basic information about composes.

compose log <UUID> [<SIZE>]

Show the last SIZE kB of the compose log.

compose cancel <UUID>

Cancel a running compose and delete any intermediate results.

compose delete <UUID,...>

Delete the listed compose results.

compose info <UUID>

Show detailed information on the compose.

compose metadata <UUID>

Download the metadata use to create the compose to <uuid>-metadata.tar

compose logs <UUID>

Download the compose logs to <uuid>-logs.tar

compose results <UUID>

Download all of the compose results; metadata, logs, and image to <uuid>.tar

compose image <UUID>

Download the output image from the compose. Filename depends on the type.

blueprints list

List the names of the available blueprints.

blueprints show <BLUEPRINT,...>

Display the blueprint in TOML format.

blueprints changes <BLUEPRINT,...>

Display the changes for each blueprint.


Display the differences between 2 versions of a blueprint. FROM-COMMIT can be a commit hash or NEWEST TO-COMMIT can be a commit hash, NEWEST, or WORKSPACE

blueprints save <BLUEPRINT,...>

Save the blueprint to a file, <BLUEPRINT>.toml

blueprints delete <BLUEPRINT>

Delete a blueprint from the server

blueprints depsolve <BLUEPRINT,...>

Display the packages needed to install the blueprint.

blueprints push <BLUEPRINT>

Push a blueprint TOML file to the server.

blueprints freeze <BLUEPRINT,...>

Display the frozen blueprint's modules and packages.

blueprints freeze show <BLUEPRINT,...>

Display the frozen blueprint in TOML format.

blueprints freeze save <BLUEPRINT,...>

Save the frozen blueprint to a file, <blueprint-name>.frozen.toml.

blueprints tag <BLUEPRINT>

Tag the most recent blueprint commit as a release.

blueprints undo <BLUEPRINT> <COMMIT>

Undo changes to a blueprint by reverting to the selected commit.

blueprints workspace <BLUEPRINT>

Push the blueprint TOML to the temporary workspace storage.

modules list

List the available modules.

projects list

List the available projects.

projects info <PROJECT,...>

Show details about the listed projects.

sources list

List the available sources

sources info <SOURCE-NAME,...>

Details about the source.

sources add <SOURCE.TOML>

Add a package source to the server.

sources change <SOURCE.TOML>

Change an existing source

sources delete <SOURCE-NAME>

Delete a package source.

status show Show API server status.

upload info <UPLOAD-UUID>

Details about an upload


Upload a build image to the selected provider.

upload log <UPLOAD-UUID>

Show the upload log

upload cancel <UPLOAD-UUID>

Cancel an upload with that is queued or in progress

upload delete <UPLOAD-UUID>

Delete the upload and remove it from the build

upload reset <UPLOAD-UUID>

Reset the upload so that it can be tried again

providers list <PROVIDER>

List the available providers, or list the <provider's> available profiles

providers show <PROVIDER> <PROFILE>

show the details of a specific provider's profile

providers push <PROFILE.TOML>

Add a new profile, or overwrite an existing one

providers save <PROVIDER> <PROFILE>

Save the profile's details to a TOML file named <PROFILE>.toml

providers delete <PROVIDER> <PROFILE>

Delete a profile from a provider

Edit a Blueprint

Start out by listing the available blueprints using composer-cli blueprints list, pick one and save it to the local directory by running composer-cli blueprints save http-server.

Edit the file (it will be saved with a .toml extension) and change the description, add a package or module to it. Send it back to the server by running composer-cli blueprints push http-server.toml. You can verify that it was saved by viewing the changelog - composer-cli blueprints changes http-server.

See the Example Blueprint for an example.

Build an image

Build a qcow2 disk image from this blueprint by running composer-cli compose start http-server qcow2. It will print a UUID that you can use to keep track of the build. You can also cancel the build if needed.

The available types of images is displayed by composer-cli compose types. Currently this consists of: alibaba, ami, ext4-filesystem, google, hyper-v, live-iso, openstack, partitioned-disk, qcow2, tar, vhd, vmdk

You can optionally start an upload of the finished image, see Image Uploads for more information.

Monitor the build status

Monitor it using composer-cli compose status, which will show the status of all the builds on the system. You can view the end of the anaconda build logs once it is in the RUNNING state using composer-cli compose log UUID where UUID is the UUID returned by the start command.

Once the build is in the FINISHED state you can download the image.

Download the image

Downloading the final image is done with composer-cli compose image UUID and it will save the qcow2 image as UUID-disk.qcow2 which you can then use to boot a VM like this:

qemu-kvm --name test-image -m 1024 -hda ./UUID-disk.qcow2

Image Uploads

composer-cli can upload the images to a number of services, including AWS, OpenStack, and vSphere. The upload can be started when the build is finished, by using composer-cli compose start ... or an existing image can be uploaded with composer-cli upload start .... In order to access the service you need to pass authentication details to composer-cli using a TOML file, or reference a previously saved profile.


With osbuild-composer you can only specify upload targets during the compose process.


Providers are the services providers with Ansible playbook support under /usr/share/lorax/lifted/providers/, you will need to gather some provider specific information in order to authenticate with it. You can view the required fields using composer-cli providers template <PROVIDER>, eg. for AWS you would run:

composer-cli upload template aws

The output looks like this:

provider = "aws"

aws_access_key = "AWS Access Key"
aws_bucket = "AWS Bucket"
aws_region = "AWS Region"
aws_secret_key = "AWS Secret Key"

Save this into an aws-credentials.toml file and use it when running start.


The access key and secret key can be created by going to the IAM->Users->Security Credentials section and creating a new access key. The secret key will only be shown when it is first created so make sure to record it in a secure place. The region should be the region that you want to use the AMI in, and the bucket can be an existing bucket, or a new one, following the normal AWS bucket naming rules. It will be created if it doesn't already exist.

When uploading the image it is first uploaded to the s3 bucket, and then converted to an AMI. If the conversion is successful the s3 object will be deleted. If it fails, re-trying after correcting the problem will re-use the object if you have not deleted it in the meantime, speeding up the process.


Profiles store the authentication settings associated with a specific provider. Providers can have multiple profiles, as long as their names are unique. For example, you may have one profile for testing and another for production uploads.

Profiles are created by pushing the provider settings template to the server using composer-cli providers push <PROFILE.TOML> where PROFILE.TOML is the same as the provider template, but with the addition of a profile field. For example, an AWS profile named test-uploads would look like this:

provider = "aws"
profile = "test-uploads"

aws_access_key = "AWS Access Key"
aws_bucket = "AWS Bucket"
aws_region = "AWS Region"
aws_secret_key = "AWS Secret Key"

You can view the profile by using composer-cli providers aws test-uploads.

Build an image and upload results

If you have a profile named test-uploads:

composer-cli compose start example-http-server ami "http image" aws test-uploads

Or if you have the settings stored in a TOML file:

composer-cli compose start example-http-server ami "http image" aws-settings.toml

It will return the UUID of the image build, and the UUID of the upload. Once the build has finished successfully it will start the upload process, which you can monitor with composer-cli upload info <UPLOAD-UUID>

You can also view the upload logs from the Ansible playbook with:

``composer-cli upload log <UPLOAD-UUID>``

The type of the image must match the type supported by the provider.

Upload an existing image

You can upload previously built images, as long as they are in the FINISHED state, using composer-cli upload start ...`. If you have a profile named test-uploads:

composer-cli upload start <UUID> "http-image" aws test-uploads

Or if you have the settings stored in a TOML file:

composer-cli upload start <UUID> "http-image" aws-settings.toml

This will output the UUID of the upload, which can then be used to monitor the status in the same way described above.


There are a couple of arguments that can be helpful when debugging problems. These are only meant for debugging and should not be used to script access to the API. If you need to do that you can communicate with it directly in the language of your choice.

--json will return the server's response as a nicely formatted json output instead of printing what the command would usually print.

--test=1 will cause a compose start to start creating an image, and then end with a failed state.

--test=2 will cause a compose to start and then end with a finished state, without actually composing anything.

Blueprint Reference

Blueprints are simple text files in TOML format that describe which packages, and what versions, to install into the image. They can also define a limited set of customizations to make to the final image.

A basic blueprint looks like this:

name = "base"
description = "A base system with bash"
version = "0.0.1"

name = "bash"
version = "4.4.*"

The name field is the name of the blueprint. It can contain spaces, but they will be converted to - when it is written to disk. It should be short and descriptive.

description can be a longer description of the blueprint, it is only used for display purposes.

version is a semver compatible version number. If a new blueprint is uploaded with the same version the server will automatically bump the PATCH level of the version. If the version doesn't match it will be used as is. eg. Uploading a blueprint with version set to 0.1.0 when the existing blueprint version is 0.0.1 will result in the new blueprint being stored as version 0.1.0.

[[packages]] and [[modules]]

These entries describe the package names and matching version glob to be installed into the image.

The names must match the names exactly, and the versions can be an exact match or a filesystem-like glob of the version using * wildcards and ? character matching.


Currently there are no differences between packages and modules in osbuild-composer. Both are treated like an rpm package dependency.

For example, to install tmux-2.9a and openssh-server-8.*, you would add this to your blueprint:

name = "tmux"
version = "2.9a"

name = "openssh-server"
version = "8.*"


The groups entries describe a group of packages to be installed into the image. Package groups are defined in the repository metadata. Each group has a descriptive name used primarily for display in user interfaces and an ID more commonly used in kickstart files. Here, the ID is the expected way of listing a group.

Groups have three different ways of categorizing their packages: mandatory, default, and optional. For purposes of blueprints, mandatory and default packages will be installed. There is no mechanism for selecting optional packages.

For example, if you want to install the anaconda-tools group you would add this to your blueprint:


groups is a TOML list, so each group needs to be listed separately, like packages but with no version number.


The [customizations] section can be used to configure the hostname of the final image. eg.:

hostname = "baseimage"

This is optional and may be left out to use the defaults.


This allows you to append arguments to the bootloader's kernel commandline. This will not have any effect on tar or ext4-filesystem images since they do not include a bootloader.

For example:

append = "nosmt=force"


Set an existing user's ssh key in the final image:

user = "root"

The key will be added to the user's authorized_keys file.


key expects the entire content of ~/.ssh/


Add a user to the image, and/or set their ssh key. All fields for this section are optional except for the name, here is a complete example:

name = "admin"
description = "Administrator account"
password = "$6$CHO2$3rN8eviE2t50lmVyBYihTgVRHcaecmeCk31L..."
home = "/srv/widget/"
shell = "/usr/bin/bash"
groups = ["widget", "users", "wheel"]
uid = 1200
gid = 1200

If the password starts with $6$, $5$, or $2b$ it will be stored as an encrypted password. Otherwise it will be treated as a plain text password.


key expects the entire content of ~/.ssh/


Add a group to the image. name is required and gid is optional:

name = "widget"
gid = 1130


Customizing the timezone and the NTP servers to use for the system:

timezone = "US/Eastern"
ntpservers = ["", ""]

The values supported by timezone can be listed by running timedatectl list-timezones.

If no timezone is setup the system will default to using UTC. The ntp servers are also optional and will default to using the distribution defaults which are fine for most uses.

In some image types there are already NTP servers setup, eg. Google cloud image, and they cannot be overridden because they are required to boot in the selected environment. But the timezone will be updated to the one selected in the blueprint.


Customize the locale settings for the system:

languages = ["en_US.UTF-8"]
keyboard = "us"

The values supported by languages can be listed by running localectl list-locales from the command line.

The values supported by keyboard can be listed by running localectl list-keymaps from the command line.

Multiple languages can be added. The first one becomes the primary, and the others are added as secondary. One or the other of languages or keyboard must be included (or both) in the section.


By default the firewall blocks all access except for services that enable their ports explicitly, like sshd. This command can be used to open other ports or services. Ports are configured using the port:protocol format:

ports = ["22:tcp", "80:tcp", "imap:tcp", "53:tcp", "53:udp"]

Numeric ports, or their names from /etc/services can be used in the ports enabled/disabled lists.

The blueprint settings extend any existing settings in the image templates, so if sshd is already enabled it will extend the list of ports with the ones listed by the blueprint.

If the distribution uses firewalld you can specify services listed by firewall-cmd --get-services in a section:

enabled = ["ftp", "ntp", "dhcp"]
disabled = ["telnet"]

Remember that the are different from the names in /etc/services.

Both are optional, if they are not used leave them out or set them to an empty list []. If you only want the default firewall setup this section can be omitted from the blueprint.

NOTE: The Google and OpenStack templates explicitly disable the firewall for their environment. This cannot be overridden by the blueprint.


This section can be used to control which services are enabled at boot time. Some image types already have services enabled or disabled in order for the image to work correctly, and cannot be overridden. eg. ami requires sshd, chronyd, and cloud-init. Without them the image will not boot. Blueprint services are added to, not replacing, the list already in the templates, if any.

The service names are systemd service units. You may specify any systemd unit file accepted by systemctl enable eg. cockpit.socket:

enabled = ["sshd", "cockpit.socket", "httpd"]
disabled = ["postfix", "telnetd"]


Currently osbuild-composer does not support repos.git

The [[repos.git]] entries are used to add files from a git repository repository to the created image. The repository is cloned, the specified ref is checked out and an rpm is created to install the files to a destination path. The rpm includes a summary with the details of the repository and reference used to create it. The rpm is also included in the image build metadata.

To create an rpm named server-config-1.0-1.noarch.rpm you would add this to your blueprint:

summary="Setup files for server deployment"
  • rpmname: Name of the rpm to create, also used as the prefix name in the tar archive

  • rpmversion: Version of the rpm, eg. "1.0.0"

  • rpmrelease: Release of the rpm, eg. "1"

  • summary: Summary string for the rpm

  • repo: URL of the get repo to clone and create the archive from

  • ref: Git reference to check out. eg. origin/branch-name, git tag, or git commit hash

  • destination: Path to install the / of the git repo at when installing the rpm

An rpm will be created with the contents of the git repository referenced, with the files being installed under /opt/server/ in this case.

ref can be any valid git reference for use with git archive. eg. to use the head of a branch set it to origin/branch-name, a tag name, or a commit hash.

Note that the repository is cloned in full each time a build is started, so pointing to a repository with a large amount of history may take a while to clone and use a significant amount of disk space. The clone is temporary and is removed once the rpm is created.

Example Blueprint

This example blueprint will install the tmux, git, and vim-enhanced packages. It will set the root ssh key, add the widget and admin users as well as a students group:

name = "example-custom-base"
description = "A base system with customizations"
version = "0.0.1"

name = "tmux"
version = "*"

name = "git"
version = "*"

name = "vim-enhanced"
version = "*"

hostname = "custombase"

user = "root"

name = "widget"
description = "Widget process user account"
home = "/srv/widget/"
shell = "/usr/bin/false"
groups = ["dialout", "users"]

name = "admin"
description = "Widget admin account"
password = "$6$CHO2$3rN8eviE2t50lmVyBYihTgVRHcaecmeCk31LeOUleVK/R/aeWVHVZDi26zAH.o0ywBKH9Tc0/wm7sW/q39uyd1"
home = "/srv/widget/"
shell = "/usr/bin/bash"
groups = ["widget", "users", "students"]
uid = 1200

name = "plain"
password = "simple plain password"

name = "bart"
groups = ["students"]

name = "widget"

name = "students"