Ansible role hosts

An Ansible role for managing the hosts file (/etc/hosts). Specifically, the responsibilities of this role are to:

• Add the default localhost entry;
• Add an entry for the host name bound to the host's default external IPv4 address (optional);
• Add entries for basic IPv6 addresses, e.g. ip6-localnet (optional);
• Add entries for Ansible managed hosts (optional);
• Add entries specified in Yaml (optional, see below);
• Add entries specified in text files (optional).

Requirements

No specific requirements

Role Variables

None of the variables below are required. When not set, the default setting is applied.

Variable	Default	Comments
hosts_add_default_ipv4	true	If true, an entry for the host name is added, bound to the host's default IPv4 address.
hosts_add_basic_ipv6	false	If true, basic IPv6 entries are added (e.g. localhost6, ip6-localnet, etc.)
hosts_add_ansible_managed_hosts	false	If true, an entry for hosts managed by Ansible is added. (†)
hosts_add_ansible_managed_hosts_groups	['all']	Control which host entries are created when using hosts_add_ansible_managed_hosts
hosts_entries	[]	A list of dicts with custom entries to be added to the hosts file. See below for an example.
hosts_file_snippets	[]	A list of files containing host file snippets to be added to the hosts file verbatim.
hosts_ip_protocol	ipv4	When adding Ansible managed hosts, this specifies the IP protocol (ipv4 or ipv6)
hosts_network_interface	{{ansible_default_ipv4.interface}}	When adding Ansible managed hosts, this specifies the network interface for which the IP address should be added.
hosts_file_backup	no	If yes, backup of host file is created with timestamp

(†) When setting hosts_add_ansible_managed_hosts, an entry for the current host will also be added. Consequently, hosts_add_default_ipv4 doesn't need to be set.

Individual hosts file entries can be added with hosts_entries, a list of dicts with keys name, ip and (optional) aliases. Example:

hosts_entries:
  - name: slashdot
    ip: 216.34.181.45
  - name: gns1
    ip: 8.8.8.8
    aliases:
      - googledns1
      - googlens1
  - name: gns2
    ip: 8.8.4.4
    aliases:
      - googledns2
      - googlens2

Dependencies

No dependencies.

Example Playbook

See the test playbook

Tests for this role are provided in the form of a Vagrant environment that is kept in a separate branch, tests. I use git-worktree(1) to include the test code into the working directory. Instructions for running the tests:

1. Fetch the tests branch: git fetch origin tests
2. Create a Git worktree for the test code: git worktree add tests tests (remark: this requires at least Git v2.5.0). This will create a directory tests/.
3. cd tests/
4. vagrant up will then create a VM and apply a test playbook (test.yml).

You may want to change the base box into one that you like. The current one, bertvv/centos72 was generated using a Packer template from the Boxcutter project with a few modifications.

Contributing

Issues, feature requests, ideas are appreciated and can be posted in the Issues section. Pull requests are also very welcome. Preferably, create a topic branch and when submitting, squash your commits into one (with a descriptive message).

License

BSD, see <LICENSE.md>

Contributors

This role was inspired by the work of soplakanets (including the contribution by astrorafael) and mivok.

• Bert Van Vreckem (maintainer)
• Dheeraj Dwivedi
• Ernestas Poskus
• Mohammed Naser