When using Ansible, it’s important to define naming conventions and to apply them for all your roles and playbooks. Here are mine.

All variables should be snake_case

The easiest rule:

myappBindIp: "127.0.0.1" # not good
myapp_bin_Ip: "127.0.0.1" # not good
myapp_bind_ip: "127.0.0.1" # good

Roles and groups names

I use kebab-case for my roles and groups names (haproxy, kafka-manager…​).

Variables defined in a role

All variables defined in a role (defaults/main.yml, vars/main.yml) should be prefixed with the role name. It prevents collisions between variables and also allows to instantly know at what role a variable belongs to. For example, a role installing HAProxy will probably need a variable specifying the version in defaults/main.yml:

version: "1.8" # not good
haproxy_version: "1.8" # good

Sometimes, it’s tempting to use the same variable name in two roles if the variables should always have the same value (because being overrided somewhere). I think it’s better to create one variable per role no matter what. For example, if we have role-a and role-b, and each one need to know a (common) database name, we could do:

role_a_database_name: "foo"

role_b_database_name: "foo"

database_name: "foo"

role_a_database_name: "{{ database_name }}"

role_b_database_name: "{{ database_name }}"

[app:children]
role-a
role-b

[role-a]
host1

[role-b]
host2

Here, each role has a specific variable defined for the database name. If the database name should always be the same, i can define a parent group (app) and two child groups (one for each role, role-a and role-b). I can now share a variable between groups in the group_vars files.

This approach avoids side effects between roles, and simplifies future refactoring.

Registered variables

I usually prefix registered variables by _<rolename>, to differentiate them from defaults variables.

Handlers names

It’s also important to name correctly your handlers. My convention is: <target> | <action>:

- name: haproxy | reload
  become: true
  service:
    name: haproxy
    state: reloaded

- name: apt | update cache
  become: true
  apt:
    update_cache: yes

Conclusion

Naming is super important. This will greatly simplify the maintenance of your Ansible projects.