ansible/docs/docsite/rst/collections_tech_preview.rst

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Collections

Collections are a distribution format for Ansible content. They can be used to package and distribute playbooks, roles, modules, and plugins. You will be able to publish and use collections through Ansible's Galaxy repository.

Important

This feature is available in Ansible 2.8 as a Technology Preview and therefore is not fully supported. It should only be used for testing and should not be deployed in a production environment. Future Galaxy or Ansible releases may introduce breaking changes.

Collection structure

Collections follow a simple data structure. None of the directories are required unless you have specific content that belongs in one of them. They do require a galaxy.yml file at the root level of the collection. This file contains all of the metadata that Galaxy and other tools need in order to package, build and publish the collection.:

collection/
├── docs/
├── galaxy.yml
├── plugins/
│   ├── modules/
│   │   └── module1.py
│   ├── inventory/
│   └── .../
├── README.md
├── roles/
│   ├── role1/
│   ├── role2/
│   └── .../
├── playbooks/
│   ├── files/
│   ├── vars/
│   ├── templates/
│   └── tasks/
└── tests/

Note

* We will only accept .yml extensions for galaxy.yml. * A full structure can be found at Draft collection * Not all directories are currently in use. Those are placeholders for future features.

galaxy.yml

This file contains the information about a collection that is necessary for Ansible tools to operate. galaxy.yml has the following fields (subject to changes and expansion):

namespace: "namespace_name"
name: "collection_name"
version: "1.0.12"
authors:
    - "Author1"
    - "Author2 (https://author2.example.com)"
    - "Author3 <author3@example.com>"
dependencies:
    "other_namespace.collection1": ">=1.0.0"
    "other_namespace.collection2": ">=2.0.0,<3.0.0"
    "anderson55.my_collection": "*"    # note: "*" selects the highest version available
license:
    - "MIT"
tags:
    - demo
    - collection
repository: "https://www.github.com/my_org/my_collection"

Required Fields:

• namespace: the namespace that the collection lives under. It must be a valid Python identifier,

  and may only contain alphanumeric characters and underscores. Additionally the namespace cannot start with underscores or numbers and cannot contain consecutive underscores.

• name: the collection's name. Has the same character restrictions as namespace.
• version: the collection's version. To upload to Galaxy, it must be compatible with semantic versioning.

Optional Fields:

• dependencies: A dictionary where keys are collections, and values are version range specifiers. It is good practice to depend on a version range to minimize conflicts, and pin to a a major version to protect against breaking changes. For example: "user1.collection1": ">=1.2.2,<2.0.0" This field allows other collections as dependencies, not traditional roles.
• description: A short summary description of the collection.
• license: Either a single license or a list of licenses for content inside of a collection. Galaxy currently only accepts SPDX licenses.
• tags: a list of tags. These have the same character requirements as namespace and name.
• repository: URL of originating SCM repository.

docs directory

Keep general documentation for the collection here. Plugins and modules will still keep their specific documentation embedded as Python docstrings. Use the docs folder to describe how to use the roles and plugins the collection provides, role requirements, and so on. Currently we are looking at Markdown as the standard format for documentation files, but this is subject to change.

We are updating ansible-doc to allow showing documentation for plugins inside a collection:

ansible-doc -t lookup mycol.myname.lookup1

The ansible-doc command requires the fully qualified collection name (FQCN) to display specific plugin documentation.

plugins directory

Add a 'per plugin type' specific subdirectory here, including module_utils which is usable not only by modules, but by any other plugin by using their FQCN. This is a way to distribute modules, lookups, filters, and so on, without having to import a role in every play.

roles directory

Collection roles are mostly the same as existing roles, but with a couple of limitations:

• Role names are now limited to contain only lowercase alphanumeric characters, plus _ and start with an alpha character.
• Roles cannot have their own plugins any more. The plugins must live in the collection plugins directory and will be accessible to the collection roles.

The directory name of the role is used as the role name. Therefore, the directory name must comply with the above role name rules. The collection import into Galaxy will fail if a role name does not comply with these rules.

You can migrate 'traditional roles' into a collection but they must follow the rules above. You man need to rename roles if they don't conform. You will have to move or link any role-based plugins to the collection specific directories.

Note

For roles imported into Galaxy directly from a GitHub repository, setting the role_name value in the role's metadata overrides the role name used by Galaxy. For collections, that value is ignored. When importing a collection, Galaxy uses the role directory as the name of the role and ignores the role_name metadata value.

playbooks directory

TBD.

tests directory

TBD. Expect tests for the collection itself, including Molecule files, to reside here.

Creating collections

This is currently is a work in progress. We created the Mazer command line tool available at the Ansible Mazer project. as a proof of concept for packaging, distributing and installing collections. You can install mazer with pip install mazer or checkout the code directly.

Note

All the documentation below that use mazer might be updated to use another tool in the future as mazer will not be updated in the future.

We are working on integrating this into Ansible itself for 2.9. Currently we have an ansible-galaxy PR incorporating some of the commands into ansible-galaxy. Currently it is not installable outside Ansible, but we hope to land this into development soon so early adopters can test.

Note

Any references to ansible-galaxy below will be of a 'working version' either in this PR or subsequently in development. As such, the command and this documentation section is subject to frequent change.

We also plan to update Ansible Molecule, for a full developer toolkit with integrated testing.

In the end, to get started with authoring a new collection it should be as simple as:

collection_dir#>ansible-galaxy collection init

And then populating the directories with the content you want inside the collection. For now you can optionally clone from https://github.com/bcoca/collection to get the directory structure (or just create the directories as you need them).

Building collections

Collections are built by running mazer build from inside the collection's root directory. This will create a releases/ directory inside the collection with the build artifacts, which can be uploaded to Galaxy.:

collection/
├── ...
├── releases/
│   └── namespace_name-collection_name-1.0.12.tar.gz
└── ...

Note

Changing the filename of the tarball in the release directory so that it doesn't match the data in galaxy.yml will cause the import to fail.

This tarball itself can be used to install the collection on target systems. It is mainly intended to upload to Galaxy as a distribution method, but you should be able to use directly.

Publishing collections

We are in the process of updating Ansible Galaxy to manage collections as it currently manages roles.

Upload from the Galaxy website

Go to the My Content page, and click the Add Content button on one of your namespaces. From the Add Content dialogue, click Upload New Collection, and select the collection archive file from your local filesystem.

When uploading collections it doesn't matter which namespace you select. The collection will be uploaded to the namespace specified in the collection metadata in the galaxy.yml file. If you're not an owner of the namespace, the upload request will fail.

Once Galaxy uploads and accepts a collection, you will be redirected to the My Imports page, which displays output from the import process, including any errors or warnings about the metadata and content contained in the collection.

Upload using mazer

You can upload collection artifacts with mazer, as shown in the following example:

mazer publish --api-key=SECRET path/to/namespace_name-collection_name-1.0.12.tar.gz

The above command triggers an import process, just as if the collection had been uploaded through the Galaxy website. Use the My Imports page to view the output from the import process.

Your API key can be found on the preferences page in Galaxy.

To learn more about Mazer, see Mazer.

Collection versions

Once you upload a version of a collection, you cannot delete or modify that version. Ensure that everything looks okay before uploading. The only way to change a collection is to release a new version. The latest version of a collection (by highest version number) will be the version displayed everywhere in Galaxy; however, users will still be able to download older versions.

Installing collections

The recommended way to install a collection is:

#> ansible-galaxy collection install mycollection -p /path

assuming the collection is hosted in Galaxy.

You can also use a tarball resulting from your build:

#> ansible-galaxy install mynamespace.mycollection.0.1.0.tgz -p /path

As a path you should use one of the values configured in COLLECTIONS_PATHS. This is also where Ansible itself will expect to find collections when attempting to use them.

You can also keep a collection adjacent to the current playbook, under a collections/ansible_collection/ directory structure.

play.yml
├── collections/
│   └── ansbile_collection/
│               └── myname/
│                   └── mycol/<collection structure lives here>

Using collections

Once installed, you can reference collection content by its FQCN:

- hosts: all
  tasks:
    - myname.mycol.mymodule:
        option1: value

This works for roles or any type of plugin distributed within the collection:

- hosts: all
  tasks:
    - include_role:
        name : myname.mycol.role1
    - myname.mycol.mymodule:
        option1: value

    - debug:
        msg: '{{ lookup("myname.mycol.lookup1", 'param1')| myname.mycol.filter1 }}'

To avoid a lot of typing, you can use the collections keyword added in Ansbile 2.8:

- hosts: all
  collections:
   - myname.mycol
  tasks:
    - include_role:
        name: role1
    - mymodule:
        option1: value

    - debug:
        msg: '{{ lookup("myname.mycol.lookup1", 'param1')| myname.mycol.filter1 }}'

This keyword creates a 'search path' for non namespaced plugin references. It does not import roles or anything else. Notice that you still need the FQCN for non-action or module plugins.