Ansible Galaxy — sharing & reusing roles

Someone has already written and battle-tested a role for "install and configure PostgreSQL" or "harden this Ubuntu box." Ansible Galaxy is the public hub for exactly that — install a community role instead of writing your own from scratch.

# search, then install a role from Galaxy
ansible-galaxy search postgres
ansible-galaxy install geerlingguy.postgresql

# now usable in any playbook, same as your own roles
- hosts: dbservers
  roles:
    - geerlingguy.postgresql

For real projects, pin exact versions in a requirements.yml file instead of installing roles ad hoc — so a fresh checkout of the repo gets the exact same roles everyone else is running.

# requirements.yml
roles:
  - name: geerlingguy.postgresql
    version: "3.4.0"

collections:
  - name: community.docker
    version: ">=3.0.0"

ansible-galaxy install -r requirements.yml
ansible-galaxy collection install -r requirements.yml

Beyond roles, Galaxy also distributes collections — bundles of modules and plugins for a specific platform, like community.docker or amazon.aws, which is how Ansible gains new modules without Ansible itself needing a new release.