[chef] Re: Antwort: Re: Testing idempotence of chef cookbooks

[Roland Moriz < >]

Am 21.05.2015 um 17:30 schrieb Ranjib Dey < " class=""> >:

yeah, its should be 0 resources updated if everything is idempotent and already converged. those two numbers relfect number of updated resources / number of total resources. Total resources is sum of all resources defined by all recipes, lwrps as part of the expanded run list, while updated resources are a subset of them which was modified (like absent file being created, absent packaged being installed etc) during the chef run.

Some resources are very hard to make „chef-idempotent“, e.g. ruby blocks. Even if you make sure your ruby code is idempotent, the execution of the block already counts as „updated resource“. Even popular community cookbooks do have that "problem“.  

You probably want to add each converge result to a temp file and calculate/check the difference or some kind of percentage instead.

regards

Roland

On Thu, May 21, 2015 at 8:01 AM, < " target="_blank" class=""> > wrote:

Isn't your way the same as running the converge command twice and looking at the last line of the chef-client output? If so, this way sounds a little bit easier for me.

        Chef Client finished, 45/61 resources updated in 16.28070151 seconds

If so, what is really the goal of testing idempotence? Should I really have a "0 resources updated"?
By the way, what do the two numbers mean actually?

regards,
Johannes




Von:        Roland Moriz < " target="_blank" class=""> >
An:         " target="_blank" class="">
Datum:        20.05.2015 13:10
Betreff:        [chef] Re: Testing idempotence of chef cookbooks

---

Hi,


Am 20.05.2015 um 10:21 schrieb " target="_blank" class=""> :

Hi,

is there a general way or best practice for testing idempotence of chef cookbooks?


An approach might be to use test-kitchen + duplicate suite names + a custom chef-handler that writes the number of updated resources to disk + serverspec to verify it.

e.g. .kitchen.yaml

-8<---
suites:
  - name: default
    run_list:
      - recipe[chef-handler]
      - recipe[build-essential]
    attributes:

  - name: default
    run_list:
      - recipe[chef-handler]
      - recipe[build-essential]
    attributes:
-8<---

this will converge the node twice on „kitchen converge“.

An example for a simple chef handler: https://github.com/jtimberman/chef-handler-updated-resources/blob/master/lib/chef/handler/updated_resources.rb - use https://supermarket.chef.io/cookbooks/chef_handler to deploy the handler to your testing node.

Instead of logging to Chef::Log you could just write the number of updated resources to a log file e.g. /tmp/updated_resources and use http://serverspec.org/resource_types.html#file to verify.

hth

best regards
Roland