# Role to encapsulate several OS specific "sub-roles" **URL:** \ **Category:** Ansible Project\ **Created:** [December 11, 2013, 10:01pm UTC](https://forum.ansible.com/t/role-to-encapsulate-several-os-specific-sub-roles/14133 "2013-12-11T22:01:19Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![sebbrochet](https://avatars.discourse-cdn.com/v4/letter/s/a9a28c/32.png) [@sebbrochet](https://forum.ansible.com/u/sebbrochet)\ **Post date:** [December 11, 2013, 10:01pm UTC](https://forum.ansible.com/t/role-to-encapsulate-several-os-specific-sub-roles/14133/1 "2013-12-11T22:01:19Z")
Hello, I’ve written a role to install and configure Apache, the role is at the moment specific to Debian. This means my role/apache/tasks/main.yml contains corresponding tasks. I need also to support CentOS. I could add corresponding tasks to the same file and add a when clause for each task, based on OS version. But it makes more sense to create a specific role for each os: apache-debian and apache-centos My main playbook, site.yml include the apache role: role: - apache I’d like my playbook to describe I want Apache installed and the apache role to install the right role based on the host OS. As a task file can’t conditionally include (yet!) a role, the only option (not tested) I’ve come so far to implement it, is to use role dependency and when clause by putting in role/apache/meta/main.yml: dependencies: - { role: apache-debian, when: “ansible\_os\_family == ‘Debian’” } - { role: apache-centos, when: “ansible\_os\_family == ‘CentOS’” } and role/apache/tasks/main.yml would be empty and just acts as a dispatcher. This way my apache role encapsulates the apache-debian and apache-centos roles, so far so good. But I’d like these sub-roles to be packaged with the apache role to be shared easily. This means they could be defined in a “roles” sub-directory of the apache role. I don’t think it’s currently possible so the sub-roles should be located at the same level than my shared apache role, which is far from perfect 🙂 Do you see other options to achieve clean role encapsulation and packaging? Thanks @sebbrochet ---
**Author:** ![sebbrochet](https://avatars.discourse-cdn.com/v4/letter/s/a9a28c/32.png) [@sebbrochet](https://forum.ansible.com/u/sebbrochet)\ **Post date:** [December 12, 2013, 1:02pm UTC](https://forum.ansible.com/t/role-to-encapsulate-several-os-specific-sub-roles/14133/2 "2013-12-12T13:02:50Z")
Replying to myself… It’s possible to reference a role using a path, i.e apache/roles/debian Then I can create my sub-roles directly under my apache role: apache \_ meta \_ main.yml \_ roles \_ centos \_ tasks \_ main.yml \_ debian \_ tasks \_ main.yml And put in apache/meta/main.yml: dependencies: - { role: apache/roles/debian, when: “ansible\_os\_family == ‘Debian’” } - { role: apache/roles/centos, when: “ansible\_os\_family == ‘RedHat’” } Only minor drawback is that with the **when** clause, all tasks are listed even if they are not executed. This could clutter the output if many tasks are not executed… root@machine ~/devops/ansible2/projects/test-role-os $ ansible-playbook -i centos.hosts site.yml PLAY [test-role-hosts] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* GATHERING FACTS \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* ok: [vps-centos] TASK: [testrole/roles/debian | say hello from your os] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* skipping: [vps-centos] TASK: [testrole/roles/centos | say hello from your os] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* changed: [vps-centos] PLAY RECAP \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* vps-centos : ok=2 changed=1 unreachable=0 failed=0 root@machine ~/devops/ansible2/projects/test-role-os $ ansible-playbook -i debian.hosts site.yml PLAY [test-role-hosts] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* GATHERING FACTS \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* ok: [vps-debian] TASK: [testrole/roles/debian | say hello from your os] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* changed: [vps-debian] TASK: [testrole/roles/centos | say hello from your os] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* skipping: [vps-debian] PLAY RECAP \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* vps-debian : ok=2 changed=1 unreachable=0 failed=0 What about a task with a **special when clause** that doesn’t output anything if it’s not executed ? Thanks @sebbrochet ---
**Author:** ![James\_Martin2](https://avatars.discourse-cdn.com/v4/letter/j/b9e5f3/32.png) [@James\_Martin2](https://forum.ansible.com/u/James_Martin2)\ **Post date:** [December 12, 2013, 2:11pm UTC](https://forum.ansible.com/t/role-to-encapsulate-several-os-specific-sub-roles/14133/3 "2013-12-12T14:11:45Z")
Here's what I do -- Prior to all my roles, I do a role called bootstrap across all of my nodes. That role performs a group\_by task: - name: Create groups based on distribution   group\_by: key={{ ansible\_distribution }} then I execute my other roles -- first I execute the OS specific role--assigned to the intersection of my group in inventory and the group created by group\_by task above--followed by the common role, that works on both OSes. - hosts: CentOS:RedHat:&riak\_cluster   gather\_facts: no   sudo: True   roles:   - { role: riak/redhat, tags: ["riak"] }   - { role: riak/common, tags: ["riak"] } - hosts: Ubuntu:&riak\_cluster   gather\_facts: no   sudo: True   roles:   - { role: riak/ubuntu, tags: ["riak"] }   - { role: riak/common, tags: ["riak"] } - James ---
**Author:** ![Brian\_Candler](https://avatars.discourse-cdn.com/v4/letter/b/5f9b8f/32.png) [@Brian\_Candler](https://forum.ansible.com/u/Brian_Candler)\ **Post date:** [December 16, 2013, 2:50pm UTC](https://forum.ansible.com/t/role-to-encapsulate-several-os-specific-sub-roles/14133/4 "2013-12-16T14:50:31Z")
You can include tasks conditionally within a role: [roles/apache/tasks/main.yml] - include: debian.yml when: ansible\_os\_family == ‘Debian’ - include: redhat.yml when: ansible\_os\_family == ‘RedHat’ # Now do stuff which is both common to Debian and RedHat As well as doing OS-specific tasks in there, you can use set\_fact to set variables conditionally. e.g. [roles/apache/tasks/debian.yml] - set\_fact: service\_name=apache2 [roles/apache/tasks/redhat.yml] - set\_fact: service\_name=httpd # In the common config: service name={{service\_name}} state=started enabled=yes (Aside: this is messy compared to dynamically pulling in a vars file as you can do in a playbook, but that feature isn’t available within a role AFAICS. But I’m with you: I believe this stuff belongs in the role, not the playbook) You will still have the annoying thing that all RedHat tasks will be shown as “skipped” on a Debian host and vice versa. You can reduce the noise a bit using > **[The Manifesto for Agentic Automation](https://aiagentmanifesto.org)** > > Governing the Shift from Automation to Autonomy. The standard for Autonomous Workflows. although if _all_ your hosts are the same type, I believe the task header is still shown.