A Rockcraft project is defined in a YAML file named rockcraft.yaml at the root of the project tree in the filesystem.

This Reference section is for when you need to know which options can be used, and how, in this rockcraft.yaml file.

Format specification#

# The name of the ROCK.
name: <name>

# (Optional) The human-readable title of the ROCK. Defaults to name.
title: <title>

# Short summary describing the ROCK.
summary: <summary>

# Long multi-line description of the ROCK.
description: |

# The ROCK version, used within the ROCK OCI tag.
version: <version>

# The system image and version the application will be layered on.
base: ubuntu:18.04 | ubuntu:20.04 | ubuntu:22:04 | bare

# (Optional) The system and version on top of which the application
# will be built. Defaults to base.
build-base: ubuntu:18.04 | ubuntu:20.04 | ubuntu:22:04

# The license, in SPDX format, of the software packaged inside the ROCK.
# This field is case insensitive.
license: <license>

# (Optional) The container entry point.
entrypoint: [<path>, ...]

# (Optional) The container command line, used as arguments for
# entrypoint. If the entrypoint is not defined, the first item in
# the cmd list the command to execute.
cmd: [<arg>, ...]

# (Optional) A list of keys and values defining the container's
# runtime environment variables.
  - <var name>: <value>

# List of architecture-specific ROCKs to be built.
# Supported architectures are: amd64, arm64, arm, i386, ppc64le, riscv64 and s390x.
  # If matching a valid architecture name, it must be the same as "build-for".
    # Host architectures where the ROCK can be built.
    # Required when "build-for" is specified, otherwise it defaults to <entry>
    build-on: [<arch>, ...]
    # (Optional) Target architecture the ROCK will be built for.
    # Defaults to <entry>.
    build-for: <arch>

# The parts used to build the application.
  <part name>:


name: hello
title: Hello World
summary: An Hello World ROCK
description: |
  This is just an example of a Rockcraft project
  for an Hello World ROCK.
version: latest
base: bare
build-base: ubuntu:22.04
license: Apache-2.0
entrypoint: [/usr/bin/hello, -t]
  - VAR1: value
  - VAR2: "other value"
    build-on: ["arm", "arm64"]
    build-on: ["s390x"]
    build-for: s390x

    plugin: nil
      - hello

Rockcraft parts#

The main building blocks of a ROCK are parts.

If this sentence sounds familiar, it’s because it is familiar! Rockcraft parts are inherited from other existing Craft tools like Snapcraft and Charmcraft.

Rockcraft parts go through the same lifecycle steps as Charmcraft and Snapcraft parts.

The way the parts’ keys and values are used in the rockcraft.yaml is exactly the same as in `snapcraft.yaml`_ (here is how you define a part).

Albeit being fundamentally identical to Snapcraft parts, Rockcraft parts actually offer some extended functionality and keywords:

  • stage-packages: apart from offering the well-known package installation behavior, in Rockcraft the stage-packages keyword actually supports chiseled packages as well (learn more about Chisel). To install a package slice instead of the whole package, simply follow the Chisel convention <packageName>_<sliceName>.


    plugin: nil
      - openssl_bins
      - ca-certificates_data

    plugin: nil
      - hello

NOTE: at the moment, it is not possible to mix packages and slices in the same stage-packages field.

Rockcraft commands#

Lifecycle commands#

Lifecycle commands can take an optional parameter <part-name>. When a part name is provided, the command applies to the specific part. When no part name is provided, the command applies to all parts.


Removes a part’s assets. When no part is provided, the entire build environment (e.g. the LXD instance) is removed.


Downloads or retrieves artifacts defined for each part.


Execute operations defined for each part on a layer over the base filesystem, potentially modifying its contents.


Builds artifacts defined for each part.


Stages built artifacts into a common staging area, for each part.


Prepare, for each part, the final payload to be packed as a ROCK, performing additional processing and adding metadata files.


This is the default lifecycle command for rockcraft.

Process parts and create the ROCK as an OCI archive file containing the project payload with the provided metadata.

Other commands#


Initializes a rockcraft project with a boilerplate rockcraft.yaml file.


Shows information about a command.