pulp_redis: Allow to configure Unix Domain Socket

[Spredzy]

This commit ensures one can configure redis so it listens to unix domain
socket (if wanted) rather than forcing it to listen on TCP socket.

Benefits of this commit has been higlighted in previous PR[1].

Also, this commit introduces pulp_redis_bind to offer an expected
experience for people using pulp/pulp_installer when it comes to
configure network services (ie. pulp_api_bind, pulp_content_bind).

fixes #6931

[1] #322

[pulpbot]

Attached issue: https://pulp.plan.io/issues/6931

[Spredzy]

This tested has been tested with the following two scenarios:

Scenario 1: Using Unix Domain Socket

- hosts: localhost
  vars:
    pulp_settings:
      secret_key: secret
      content_origin: "http://{{ ansible_fqdn }}"
      x_pulp_api_host: "{{ pulp_api_host }}"
      x_pulp_api_port: "{{ pulp_api_port }}"
      x_pulp_api_user: "admin"
      x_pulp_api_password: "{{ pulp_default_admin_password }}"
      x_pulp_api_prefix: "pulp_ansible/galaxy/automation-hub/api"
      galaxy_require_content_approval: "False"
      redis_url: 'unix:///var/run/redis/redis.sock'
    pulp_default_admin_password: password
    pulp_install_plugins:
      pulp-ansible: {}
      galaxy-ng: {}
      pulp-container: {}
    pulp_api_workers: 4
    pulp_redis_bind: 'unix:/var/run/redis/redis.sock'
  roles:
    - pulp_redis
    - pulp_database
    - pulp_workers
    - pulp_resource_manager
    - pulp_webserver
    - pulp_content
    - chouseknecht.ansible_galaxy_config
  environment:
    DJANGO_SETTINGS_MODULE: pulpcore.app.settings

Scenario 2: Using the defaults value for pulp_redis_bind 127.0.0.1:6379

- hosts: localhost
  vars:
    pulp_settings:
      secret_key: secret
      content_origin: "http://{{ ansible_fqdn }}"
      x_pulp_api_host: "{{ pulp_api_host }}"
      x_pulp_api_port: "{{ pulp_api_port }}"
      x_pulp_api_user: "admin"
      x_pulp_api_password: "{{ pulp_default_admin_password }}"
      x_pulp_api_prefix: "pulp_ansible/galaxy/automation-hub/api"
      galaxy_require_content_approval: "False"
    pulp_default_admin_password: password
    pulp_install_plugins:
      pulp-ansible: {}
      galaxy-ng: {}
      pulp-container: {}
    pulp_api_workers: 4
  roles:
    - pulp_database
    - pulp_workers
    - pulp_resource_manager
    - pulp_webserver
    - pulp_content
    - chouseknecht.ansible_galaxy_config
  environment:
    DJANGO_SETTINGS_MODULE: pulpcore.app.settings

Both have deployed successfully, and the following can be observed in /pulp/v3/api/status:

"redis_connection": {
        "connected": true
 },

[fao89]

Nice!

[fao89]

I liked these ensure tasks

[mikedep333]

Awesome! See 1 suggestion.