Re: aarch64 conditional ansible stanza

[Thierry Delamare <t.delamare@laposte.net>]

On 04/07/2016 06:09 PM, Loic Dachary wrote:
>
> On 07/04/2016 17:49, Thierry Delamare wrote:
>>
>> On 04/07/2016 04:07 PM, Loic Dachary wrote:
>>> On 07/04/2016 15:58, Thierry Delamare wrote:
>>>> On 04/07/2016 08:46 AM, Loic Dachary wrote:
>>>>> Hi Thierry,
>>>>>
>>>>> In order to only install a template on architectures that are not aarch64, I changed
>>>>>
>>>>> - name: Add sources list
>>>>>      template:
>>>>>        dest: /etc/apt/sources.list
>>>>>        src: "../../templates/apt/sources.list.{{ ansible_distribution_release | lower }}"
>>>>>        owner: root
>>>>>        group: root
>>>>>        mode: 0644
>>>>>      register: sources
>>>>>
>>>>> into
>>>>>
>>>>> - name: Add sources list
>>>>>      template:
>>>>>        dest: /etc/apt/sources.list
>>>>>        src: "../../templates/apt/sources.list.{{ ansible_distribution_release | lower }}"
>>>>>        owner: root
>>>>>        group: root
>>>>>        mode: 0644
>>>>>      register: sources
>>>>>      when: {{ansible_architecture}} != aarch64
>>>>>
>>>>> Is there a better way to do that ?
>>>> Bonjour Loic,
>>>>
>>>> Using when statement is the correct way to add conditions to a task,
>>>> but don't forget that the when clause contains a Jinja2 expression (not like a module argument),
>>>> Thus the correct expression should rather be « when: ansible_architecture != 'aarch64' ».
>>> Indeed, the previous attempt failed :-) Here is a more elaborate version that also excludes some packages that are not available in the aarch64 repositories. How does that look ?
>>>
>>> https://github.com/ceph/ceph-cm-ansible/pull/224/commits/80e1cb2f3688393f4238268a543e6c3ab19bae75
>>>
>> That looks good to me, but.
>> You could also use the already existing scheme for defining vars or even including plays depending on distribution or (if you take care of it) architecture.
>> I mean that you could create a roles/testnode/tasks/setup-ubuntu-aarch32.yml with only the needed tasks (instead of conditionally exclude most of them in roles/testnode/tasks/setup-ubuntu.yml) and change roles/testnode/tasks/main.yml to add « - { include: setup-ubuntu-aarch32.yml, when: ansible_distribution == "Ubuntu" and ansible_architecture == 'aarch32' } » (maybe you also want to rename setup-ubuntu.yml as setup-ubuntu-aarch64.yml and change main.yml accordingly)
>> If the common part between aarch32 and aarch64 duplicate to much, keep a common setup-ubuntu.
> I did that, it looks better :-)
>
>> Similarly for packages lists (more usual), add roles/testnode/vars/ubuntu-aarch64.yml and ubuntu-aarch32.yml for respective specific packages and use an include_vars directive using ansible_distribution and ansible_architecture once in roles/testnode/tasks/vars.yml instead of many when clauses.
> I'm not sure I get where the simplification is. When I try this, I end up with more indirection levels and it feels more complicated.
I don't say it's the simplest way to get your changes done, but it look 
like more coherent with existing scheme (itself familiar to ansible 
users) and probably will be easier to find and evolve for newcomers 
(main include vars which include version dependent files defining 
version dependent vars)
>   
>
>> PS: Maybe you could teach me how to boostrap a working env next time we cowork.
> You should be able to follow the HOWTO at http://dachary.org/?p=3939 when you get a chance :-) Or I'll show you.
Thanks for the link. I will try.

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