rockcraft.yaml

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

name

Type: string

Required: Yes

The name of the rock. This value must conform with Pebble’s format for layer files, meaning that the name:

  • must start with a lowercase letter [a-z];

  • must contain only lowercase letters [a-z], numbers [0-9] or hyphens;

  • must not end with a hyphen, and must not contain two or more consecutive hyphens.

title

Type: string

Required: No

The human-readable title of the rock. If omitted, defaults to name.

summary

Type: string

Required: Yes

A short summary describing the rock.

description

Type: string

Required: Yes

A longer, possibly multi-line description of the rock.

version

Type: string

Required: Yes

The rock version, used to tag the OCI image and name the rock file.

base

Type: One of ubuntu@20.04 | ubuntu@22.04 | ubuntu@24.04 | bare

Required: Yes

The base system image that the rock’s contents will be layered on. This is also the system that will be mounted and made available when using Overlays. The special value bare means that the rock will have no base system at all, which is typically used with static binaries or Chisel slices.

Note

The notation “ubuntu:<channel>” is also supported for some channels, but this format is deprecated and should be avoided.

build-base

Type: One of ubuntu@20.04 | ubuntu@22.04 | ubuntu@24.04 | devel

Required: Yes, if base is bare

The system and version that will be used during the rock’s build, but not included in the final rock itself. It comprises the set of tools and libraries that Rockcraft will use when building the rock’s contents. This field is mandatory if base is bare, but otherwise it is optional and defaults to the value of base.

Note

The notation “ubuntu:<channel>” is also supported for some channels, but this format is deprecated and should be avoided.

Note

devel is a “special” value that means “the next Ubuntu version, currently in development”. This means that the contents of this system changes frequently and should not be relied on for production rocks.

license

Type: string, in SPDX format

Required: No

The license of the software packaged inside the rock. This must either be “proprietary” or match the SPDX format. It is case insensitive (e.g. both MIT and mit are valid).

run-user

Type: string

Required: No

The default OCI user. It must be a supported shared user. Currently, the only supported shared user is “_daemon_” (with UID/GID 584792). It defaults to “root” (with UID 0).

environment

Type: dict

Required: No

A set of key-value pairs specifying the environment variables to be added to the base image’s OCI environment.

Note

String interpolation is not yet supported so any attempts to dynamically define environment variables with $ will end in a project validation error.

services

Type: dict, following the Pebble Layer Specification format

Required: No

A list of services for the Pebble entrypoint. It uses Pebble’s layer specification syntax exactly, with each entry defining a Pebble service. For each service, the override and command fields are mandatory, but all others are optional.

entrypoint-service

Type: string

Required: No

The optional name of the Pebble service to serve as the OCI entrypoint. If set, this makes Rockcraft extend ["/bin/pebble", "enter"] with ["--args", "<serviceName>"]. The command of the Pebble service must contain an optional argument that will become the OCI CMD.

Warning

This option must only be used in cases where the targeted deployment environment has unalterable assumptions about the container image’s entrypoint.

checks

Type: dict, following the Pebble Layer Specification format

Required: No

A list of health checks that can be configured to restart Pebble services when they fail. It uses Pebble’s layer specification syntax, with each entry corresponding to a check. Each check can be one of three types: http, tcp or exec.

platforms

Type: dict

Required: Yes

The set of architecture-specific rocks to be built. Supported architectures are: amd64, arm64, armhf, i386, ppc64el, riscv64 and s390x.

Entries in the platforms dict can be free-form strings, or the name of a supported architecture (in Debian format).

Warning

All target architectures must be compatible with the architecture of the host where Rockcraft is being executed (i.e. emulation is not supported at the moment).

platforms.<entry>.build-on

Type: list[string]

Required: Yes, if build-for is specified or if <entry> is not a supported architecture name.

Host architectures where the rock can be built. Defaults to <entry> if that is a valid, supported architecture name.

platforms.<entry>.build-for

Type: string | list[string]

Required: Yes, if <entry> is not a supported architecture name.

Target architecture the rock will be built for. Defaults to <entry> that is a valid, supported architecture name.

Note

At the moment Rockcraft will only build for a single architecture, so if provided build-for must be a single string or a list with exactly one element.

parts

Type: dict

Required: Yes

The set of parts that compose the rock’s contents (see Parts).

Note

The fields entrypoint, cmd and env are not supported in Rockcraft. All rocks have Pebble as their entrypoint, and thus you must use services to define your container application.

extensions

Type: list[string]

Required: No

Extensions to enable when building the ROCK.

Currently supported extensions:

  • flask-framework

  • django-framework

  • go-framework

  • fastapi-framework

Example

name: hello
title: Hello World
summary: An Hello World rock
description: |
  This is just an example of a Rockcraft project
  for a Hello World rock.
version: latest
base: bare
build-base: [email protected]
license: Apache-2.0
run-user: _daemon_
environment:
  FOO: bar
services:
  hello:
    override: replace
    command: /usr/bin/hello -t
    environment:
      VAR1: value
      VAR2: "other value"
platforms:
  amd64:
  armhf:
    build-on: ["armhf", "arm64"]
  ibm:
    build-on: ["s390x"]
    build-for: s390x
parts:
  hello:
    plugin: nil
    stage-packages:
      - hello