Docker

|galaxy|

Ansible role to install and configure Docker container engine on RHEL/CentOS 7.

Main features:

• Supports overlay2 and devicemapper (with direct LVM) Docker storage drivers.
• Uses container-storage-setup (also known as docker-storage-setup) to set up Docker's storage.
• Prevents users from running devicemapper driver on a loopback device by default_.
• Sets up convenient passwordless sudo access for running Docker for selected users as recommended by Dan Walsh_, lead of Red Hat's Docker team.
• Supports authenticating with private Docker registries.

Limitations:

• Automatically applying changes to the Docker storage configuration for an existing system is not supported. You will have to manually remove the contents of the /var/lib/docker directory and then run the role again.

.. |galaxy| image:: https://img.shields.io/ansible/role/25555.svg :target: https://galaxy.ansible.com/tjanez/docker/ :alt: Ansible Role

.. _on a loopback device by default: https://www.projectatomic.io/blog/2015/06/notes-on-fedora-centos-and-docker-storage-drivers/ .. _as recommended by Dan Walsh: http://www.projectatomic.io/blog/2015/08/why-we-dont-let-non-root-users-run-docker-in-centos-fedora-or-rhel/

Requirements

This role requires Ansible 2.4 or higher.

It also requires RHEL/CentOS 7.4 or higher since OverlayFS support for SELinux has been added in that version.

Role Variables

Variables in defaults/main.yml: ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

+-----------------------------------------+---------+---------------------------------------------+ | Name | Type | Description | +=========================================+=========+=============================================+ | docker_enable | boolean | Indicates whether the role is enabled. | +-----------------------------------------+---------+---------------------------------------------+ | docker_storage_driver | string | Storage driver to be used with Docker. It | | | | can be one of the following: | | | | | | | | * overlay2: Use OverlayFS. | | | | * devicemapper: Use Device Mapper | | | | kernel framework. | | | | * "": Don't do any storage setup with | | | | docker-storage-setup. | | | | | | | | NOTE: The overlay storage driver is | | | | omitted since overlay2 is more | | | | performant. | +-----------------------------------------+---------+---------------------------------------------+ | docker_storage_volumegroup | string | Name of the LVM volume group to use for | | | | Docker storage. | | | | | | | | NOTE: If the value is "", the role | | | | will not configure Docker storage's | | | | volume group. | | | | | | | | NOTE: This variable must be changed | | | | from the default value if the | | | | docker_storage_driver variable is set | | | | to devicemapper. | +-----------------------------------------+---------+---------------------------------------------+ | docker_sudo_users | list | List of users for which to configure | | | | passwordless sudo access for running | | | | Docker of the form: | | | | | | | | .. code-block:: yaml | | | | | | | | name: string | | | | test (optional): boolean | | | | | | | | where name represents user's name and | | | | test indicates whether to test that | | | | convenience alias for running Docker | | | | works (defaults to true). | +-----------------------------------------+---------+---------------------------------------------+ | docker_private_registries | list | List of private Docker registries with | | | | which to authenticate the current system | | | | user of the form: | | | | | | | | .. code-block:: yaml | | | | | | | | registry_url: string | | | | username: string | | | | password: string | | | | email: string | | | | | | | | where registry_url (optional) | | | | represents registry's URL, username | | | | represents user name with which to | | | | authenticate with the registry, | | | | password represents the user's | | | | password and email (optional) | | | | represents the user's email address. | | | | | | | | NOTE: email is required when | | | | authenticating with Docker Hub_. | +-----------------------------------------+---------+---------------------------------------------+

.. _Docker Hub: https://hub.docker.com/

Dependencies

None.

Example Playbook

.. code-block:: yaml

- hosts: all

  vars:
    docker_storage_volumegroup: dockervg
    docker_sudo_users:
      - alice
      - bob

  roles:
    - docker

License

GPLv3

Author Information

Tadej Janež