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<title> Collections in Ansible 2.9+ </title> <textarea id="source">

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Collections in Ansible 2.9+

Daniel Mellado - Senior Software Engineer - Red Hat

Ansible Automates Zagreb, 11.12.2019

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Agenda

1. What's a Collection?
2. Demo Time!

Slides available at: https://danielmellado.github.io/ansible_automates_zagreb

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What's a Collection?

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Collections

What's a Collection?

• A new wat to distribute Ansible content
  • An artifact format for consistent content structure
  • Contains 1-N of roles, modules, plugins and module utilities
  • Enables versioning of external content
  • Enables consistent delivery independent of Ansible distributions
  • Installable as system, user or project resources
• Immediate use of the content found within the artifact
• Namespacing support built into the collection

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Collections

What problems do collections solve?:

• Difficult distribution of non-role content --

• Plugin/role name collisions --

• Difficult code-sharing for most plugins

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Collections

Problem 1: Content Distribution

• Multiple roles with deps? Good luck.

• Roles already distribute plugins- done?

  • Requires role to be "entered" (see also ansible-wtf)
  • Plugins are not "first-class citizens"
  • Versioning/maintenance issues

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Collections

Content Distribution with Collections

• Collection may contain 1-N:

  • Roles/Modules/Plugins
  • Playbooks (future/TBD)

• Collection is the unit of distribution and versioning

• Installable:

  • globally
  • per-user
  • content-adjacent (ie per-project)

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Collections

Instaqlling collections content

• Default paths (searched in this order, configurable)

  • (current playbook)/collections
  • ~/.ansible/collections
  • usr/share/ansible/collections

• Mazer/ansible-galaxy

• Content Hub

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Collections

Problem 2: Name Collisions

• Ansible has a global(ish) flat plugin namespace

• Role1 and Role2 both distribute my_module

  • Which one will get used? (ha!)
  • Can I use them both in the same run? (no
  • What if core later includes a my_module? (screwed)
  • What if the project has in library/ ?
  • What if the user has in ~/.ansible/?
  • What if the system has in /usr/share/ansible ?
  • Issue exists for roles and all modules/plugins

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Collections

Namespacing with Collections

• Collections have a namespace and name

  • For distribution, namespace == Galaxy user/org

• Content in collections is accessed by namespace

  • mynamespace.mycollection.my_module
  • f5.bigip.provisioning_role

• Built-in collections

  • ansible.builtin
  • ansible.legacy

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Collections

Sample Playbook

- hosts: somehosts
  tasks:
  - myns.mycollection.athing:

  - ansible.builtin.ping: # use only the ping packaged in core

  - ansible.legacy.ping: # use core or library(etc)/ping.py
    when: thing | myns.mycollection.filter == 42

  - ping: # still works, == ansible.legacy.ping:

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That's awfully verbose

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Collections

Enter the collections keyword

- hosts: somehosts
  collections:
  - ansible.builtin
  - myns.mycollection
  - otherns.othercollection
  tasks:
  - mymodule: # first found in the list of  collections
  - otherns.othercollection.mymodule: # fully-qualified is fine

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Collections

Problem 3: Code Sharing

• module_utils only works for modules
  • unless you're "in the box"
  • perverse incentives
• eg, Azure/AWS want to share utility code between
  • modules/actions/inventory/lookup plugins
• Just use pip!

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Collections

Code sharing in Collections

• Entire collection is a Python namespace package
• All installed collection content is accessible
  • even across collections!
  • ansible_collections root Python namespace
  • ansible_collections.mynamespace.mycollection

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Demo time!

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.medium-text[ Slides are available on

http://creativecommons.org/licenses/by/4.0/ ]

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Q&A

Thank you!

Slides can be found at:

• https://github.com/danielmellado/ansible_automates_zagreb

Daniel Mellado

[email protected] dmellado (freenode)

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