flichtenheld/puppet-resolver

Configure system resolver

puppet-resolver

Manage DNS resolver configurations on Linux and Windows systems. The module supports several different methods of DNS resolver configuration:

• dhclient
• sysconfig
• systemd-resolved
• windows

Other methods can be added relatively easily.

Sane defaults for the DNS resolver method have been provided for all supported operating systems:

• Ubuntu 16.04 (dhclient)
• Ubuntu 18.04, 20.04, 22.04 (systemd-resolved)
• CentOS/Red Hat 7 (sysconfig)
• CentOS/Rocky/Red Hat 8 (sysconfig)
• Windows (windows)

However, should the defaults fail the method can be selected manually.

General usage

In most cases you should be able to just use the defaults:

class { 'resolver':
  servers => ['10.10.10.1', '10.10.10.2'],
  domains => ['example.org', 'example.com'],
}

Note that some methods do not supports the domains parameter at all, or may only support it partially.

Note that method defaults only works for the officially supported operating systems, that is, those that have proper module-level Hiera data. On unsupported operating systems catalog configuration will fail unless you explicitly define the method parameter.

Also note that the default methods may not be correct in all cases. For example some Cloud images may be configured to use different method out of box than what this module expects.

Methods

dhclient

Example usage:

class { 'resolver':
  method  => 'dhclient',
  servers => ['10.10.10.1', '10.10.10.2'],
}

Notes:

• The domains parameter is not supported

netplan

The netplan method is somewhat dangerous as it touches network interface settings instead of just DNS settings. Therefore it has to enabled explicitly using the resolver::netplan::interface define and does not have a convenience wrapper in the main class. It takes the exact same parameters as resolver::systemd_resolved::interface. Using the netplan method is the only way to properly customize DNS servers on Ubuntu 20.04 in Amazon EC2, for example.

sysconfig

The sysconfig method depends on ifup being available. Older versions of Rocky Linux 8 had that installed out of the box, but newer ones don't. For the newer ones you need to install NetworkManager-initscripts-updown package to get ifup.

Example usage:

class { 'resolver':
  method    => 'sysconfig',
  servers   => ['10.10.10.1', '10.10.10.2'],
  domains   => ['example.org'],
  interface => 'eth0',
}

Notes:

• The domains parameter is optional
• If interface is not defined, Puppet defaults to using the primary network interface ($facts['networking']['primary'])
• If more than one domain is defined, only the first one is used

systemd-resolved

To configure global settings:

class { 'resolver':
  method    => 'systemd-resolved',
  servers   => ['10.10.10.1', '10.10.10.2'],
  domains   => ['example.org', 'example.com'],
}

Note that global settings may not have the intended effect as per-link settings may take precedence over them.

To configure settings for an interface (this is a wrapper for resolver::systemd_resolved::interface):

class { 'resolver':
  method    => 'systemd-resolved',
  servers   => ['10.10.10.1', '10.10.10.2'],
  domains   => ['example.org', 'example.com'],
  interface => 'eth0',
}

If you need to configure resolvers for more than one interface you can use the resolver::systemd_resolved::interface define:

resolver::systemd_resolved::interface { 'eth0':
  servers   => ['10.10.10.1', '10.10.10.2'],
  domains   => ['example.org', 'example.com'],
  interface => 'eth0',
}

resolver::systemd_resolved::interface { 'eth1':
  servers   => ['10.20.20.1', '10.20.20.2'],
  domains   => ['foo.org', 'bar.com'],
  interface => 'eth1',
}

Notes:

• The domains parameter is optional
• Multiple domains are supported
• If systemd-resolved has already obtained domain information from elsewhere it does not get overwritten (yet). This can cause unexpected behavior and/or flickering on Puppet runs.

windows

Example usage:

class { 'resolver':
  method  => 'windows,
  servers => ['10.10.10.1', '10.10.10.2'],
}

Notes:

• The domains parameter is not supported

Custom facts

systemd_resolve_status

If systemd-resolved is running this fact should contain a hash with DNS settings for each interface. For example:

{
  Global => {
  }
  eth0 => {
    dns_domain => [
      "example.org"
    ],
    dns_servers => [
      "10.10.10.1",
      "10.10.10.2"
    ]
  },
  eth1 => {
    dns_domain => [
      "example.com"
    ],
    dns_servers => [
      "10.20.20.1",
      "10.20.20.2"
    ]
  },
  eth2 => {
    dns_servers => [
      "10.30.30.1",
      "10.30.30.2"
    ]
  },
  eth3 => {
  }
}

systemd_resolved_active

This fact returns true if "systemctl is-active systemd-resolve" returns 0 and false otherwise.