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Dnsmasq

An Ansible role for setting up Dnsmasq under CentOS/RHEL 7 and Fedora 16 or newer as a simple DNS forwarder, and/or DHCP server. Specifically, the responsibilities of this role are to install the necessary packages and manage the configuration.

Configuring the firewall is outside the scope of this role. Use another role suitable for your distribution, e.g. bertvv.el7.

If you like/use this role, please consider starring it. Thanks!

Requirements

No specific requirements.

Role Variables

None of the variables below are required.

Variable Default Comments
dnsmasq_addn_hosts - Set this to specify a custom host file that should be read in addition to /etc/hosts.
dnsmasq_authoritative false When true, dnsmasq will function as an authoritative name server.
dnsmasq_bogus_priv true When true, Dnsmasq will not forward addresses in the non-routed address spaces.
dnsmasq_dhcp_hosts - Array of hashes specifying IP address reservations for hosts, with keys name (optional), mac and ip for each reservation. See below.
dnsmasq_dhcp_ranges - Array of hashes specifying DHCP ranges (with keys start_addr, end_addr, and lease_time) for each address pool. This also enables DHCP. See below.
dnsmasq_domain_needed true When true, local requests (i.e. without domain name) are not forwarded.
dnsmasq_domain - The domain for Dnsmasq.
dnsmasq_expand_hosts false Set this (and dnsmasq_domain) if you want to have a domain automatically added to simple names in a hosts-file.
dnsmasq_listen_address - The IP address of the interface that should listen to DNS/DHCP requests.
dnsmasq_interface - The network interface that should listen to DNS/DHCP requests.
dnsmasq_option_router - The default gateway to be sent to clients.
dnsmasq_port - Set this to listen on a custom port.
dnsmasq_resolv_file - Set this to specify a custom resolv.conf file.
dnsmasq_upstream_servers - Set this to specify the IP address of upstream DNS servers directly. You can specify one ore more servers as a list.
dnsmasq_srv_hosts - Array of hashes specifying SRV records, with keys name (mandatory), target, port, priority and weight for each record. See below.

DNS settings

One or more upstream DNS servers can can be specified with the variable dnsmasq_server, e.g.:

    dnsmasq_upstream_servers: ns1.example.com
  OR
    dnsmasq_upstream_servers:
      - 8.8.4.4
      - 8.8.8.8

SRV records (see dnsmasq(8) or RFC 2782) can be specified with dnsmasq_srv_hosts, e.g.:

    dnsmasq_srv_hosts:
      - name: _ldap._tcp.example.com
        target: ldap01.example.com
        port: 389
      - name: _ldap._tcp.example.com
        target: ldap02.example.com
        port: 389

DHCP settings

A DHCP range can be specified with the variable dnsmasq_dhcp_ranges, e.g.:

    dnsmasq_dhcp_ranges:
      - start_addr: '192.168.6.150'
        end_addr: '192.168.6.253'
        lease_time: '8h'

IP address reservations based on MAC addres can be specified with dnsmasq_dhcp_hosts, e.g.:

    dnsmasq_dhcp_hosts:
      - name: 'alpha'
        mac: '11:22:33:44:55:66'
        ip: '192.168.6.10'
      - name: 'bravo'
        mac: 'aa:bb:cc:dd:ee:ff'
        ip: '192.168.6.11'

Dependencies

None, but role bertvv.hosts may come in handy if you want an easy way to manage the contents of /etc/hosts.

Example Playbook

Most Dnsmasq settings have sane defaults and don't have to be specified. The simplest configuration would be a DNS forwarder with default settings:

- hosts: server
  roles:
    - bertvv.dnsmasq

A more elaborate example, with DHCP can be found in the test playbook.

Testing

Setting up the test environment

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 test VMs for all supported distros and apply a test playbook (test.yml) to each one.

Running the tests

The directory also contains a set of functional tests that validate whether the Dnsmasq service actually works on the supported distributions. You can run the tests from the host system by executing the script runtests.sh. When needed, the script will install BATS, a testing framework for Bash.

Hostname IP
`centos72-dnsmasq 192.168.6.66
`fedora23-dnsmasq 192.168.6.67

Run the test script from within its containing directory. If successful, you should see the following output:

$ ./runtests.sh
--- Running tests for host 192.168.6.66 ---
 ✓ The `dig` command should be installed
 ✓ Forward lookups
 ✓ Reverse lookups

3 tests, 0 failures
--- Running tests for host 192.168.6.67 ---
 ✓ The `dig` command should be installed
 ✓ Forward lookups
 ✓ Reverse lookups

3 tests, 0 failures

In the console transcript above, the output of installing BATS is not shown.

See also

Debian/Ubuntu users can take a look at Debops's Dnsmasq role.

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

Licensed under the 2-clause "Simplified BSD License". See LICENSE.md for details.

Contributors