What's New in v2 - AnsibleFest London 2015

WHAT'S NEW IN V2JAMES CAMMARATA

(GITHUB: JIMI-C)

ABOUT MEDirector of Ansible Core Engineering

Started contributing to Cobbler in September of 2008, and tookover the project leadership in 2010

Joined Ansible in July, 2013

WHAT IS V2?

An effort to refactor portions of Ansible's core executor engine.

WHY V2?

TECHNICAL DEBTAnsible has grown organically at a very rapid rate for 3 years.Some early design descisions have had additional featuresbolted on without concern for the overall system architecture.It was getting to the point where it was difficult to fix bugsand/or add new features without things breaking inunexpected ways.Difficulty of testing, especially in terms of python unit tests, didnot help.

NEW FEATURES IN V2:

IMPROVED ERROR MESSAGESPlaybook errors not related to syntax will (in most cases) stillshow the file along with the line and column where the error

occurred.

IMPROVED ERROR EXAMPLE:ERROR! no action detected in task

The error appears to have been in '/path/to/bad/playbook/site.yml':line 4, column 16, but may be elsewhere in the file depending on theexact syntax problem.

The offending line appears to be:

tasks: - bad_module: ̂ here

BLOCKSProvides a method for catching errors during task execution,as well as an option to always execute some set of tasksregardless of whether an exception occurred or not.Currently uses syntax similar to Ruby (begin/rescue/always)but will probably be changed to be more Pythonic(try/except/finally).

BLOCK EXAMPLE:tasks: - block: - command: /bin/false - debug: msg="you shouldn't see me" rescue: - debug: msg="this is the rescue" - command: /bin/false - debug: msg="you shouldn't see this either" always: - debug: msg="this is the always block, it will always be seen" when: foo != "some value" tags: - foo - bar

EXECUTION STRATEGY PLUGINSAllows changes in the way tasks are executed:

linear - traditional Ansible, which waits for all hosts tocomplete a task before continuingfree - allows each host to process tasks as fast as possible,without waiting for other hostsAnd anything else people can conceive - just write a new pluginfor it!

STRATEGY EXAMPLE:- hosts: all gather_facts: false strategy: free vars: ... vars_files: ... tasks: ...

EXECUTION-TIME EVALUATION OF INCLUDETASKS

Should allow the return use of include + with* actions.

INCLUDE + WITH EXAMPLE:- hosts: all gather_facts: false tasks: - include: foo.yml some_var={{item}} with_items: - a - b - c

IMPROVED VARIABLE MANAGEMENTA new class (VariableManager) controls the order and source of

variables to avoid flattening things too early.

Playbook objects now use a `post_validate` method, whichtemplates all fields in one shot, as opposed to the piece-meal way

we currently template field values.

BETTER USE OF OOPMore classes, with an emphasis on each class doing one thing

only.

More use of inheritance, especially in the plugin systems.

Well defined interactions between classes.

End-goal is better ability to write unit tests.

WHAT WILL BREAK?

PLAYBOOKSNothing. We are aiming for 100% backwards-compatibility.

INTERNAL APISPlugin APIs are changing. Connection, action, and some others

will be different.

We plan on writing a transition guide for authors of plugins, tomake it easier to move them to be compatible with V2.

WHEN WILL IT BEREADY?

V2 CAN BE TESTED TODAY!$ git clone https://github.com/ansible/ansible.git$ cd ansible$ . v2/hacking/env-setup

profit!

We are targeting March 2015 for the switchover on the develbranch.

Ansible 1.9 will be released before the switchover, and will be thelast major release using the 'v1' code.

The original code will still be available in the source tree, with itsown `hacking` script available should people wish to continue

using it from checkout.

SPEAKING OF 1.9...

As noted above, we are aiming for a release in early-mid March.

This release will primarily be about bug fixes and new modules inthe "extras" repo, but will also introduce support forPowerBroker authentication in addition to su/sudo..

This version will also introduce the use of official releasecandidates for testing.

QUESTIONS?

THANKS!