auto

README

auto

Name

auto - enables serving zone data from an RFC 1035-style master file, which is automatically picked up from disk.

Description

The auto plugin is used for an "old-style" DNS server. It serves from a preloaded file that exists on disk. If the zone file contains signatures (i.e. is signed, i.e. using DNSSEC) correct DNSSEC answers are returned. Only NSEC is supported! If you use this setup you are responsible for re-signing the zonefile. New or changed zones are automatically picked up from disk.

Syntax

auto [ZONES...] {
    directory DIR [REGEXP ORIGIN_TEMPLATE [TIMEOUT]]
    no_reload
    upstream [ADDRESS...]
}

ZONES zones it should be authoritative for. If empty, the zones from the configuration block are used.

• directory loads zones from the specified DIR. If a file name matches REGEXP it will be used to extract the origin. ORIGIN_TEMPLATE will be used as a template for the origin. Strings like {<number>} are replaced with the respective matches in the file name, e.g. {1} is the first match, {2} is the second. The default is: db\.(.*) {1} i.e. from a file with the name db.example.com, the extracted origin will be example.com. TIMEOUT specifies how often CoreDNS should scan the directory; the default is every 60 seconds. This value is in seconds. The minimum value is 1 second.
• no_reload by default CoreDNS will try to reload a zone every minute and reloads if the SOA's serial has changed. This option disables that behavior.
• upstream defines upstream resolvers to be used resolve external names found (think CNAMEs) pointing to external names. ADDRESS can be an IP address, an IP:port or a string pointing to a file that is structured as /etc/resolv.conf. If no ADDRESS is given, CoreDNS will resolve CNAMEs against itself.

All directives from the file plugin are supported. Note that auto will load all zones found, even though the directive might only receive queries for a specific zone. I.e:

. {
    auto example.org {
        directory /etc/coredns/zones
    }
}

Will happily pick up a zone for example.COM, except it will never be queried, because the auto directive only is authoritative for example.ORG.

Examples

Load org domains from /etc/coredns/zones/org and allow transfers to the internet, but send notifies to 10.240.1.1

. {
    auto org {
        directory /etc/coredns/zones/org
        transfer to *
        transfer to 10.240.1.1
    }
}

Load org domains from /etc/coredns/zones/org and looks for file names as www.db.example.org, where example.org is the origin. Scan every 45 seconds.

org {
    auto {
        directory /etc/coredns/zones/org www\.db\.(.*) {1} 45
    }
}

Documentation

Overview

Package auto implements an on-the-fly loading file backend.

Package auto implements a on-the-fly loading file backend.

Index

• type Auto
  • func (a Auto) Name() string
  • func (a Auto) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error)
  • func (a Auto) Walk() error
• type Zones
  • func (z *Zones) Add(zo *file.Zone, name string)
  • func (z *Zones) Names() []string
  • func (z *Zones) Origins() []string
  • func (z *Zones) Remove(name string)
  • func (z *Zones) Zones(name string) *file.Zone

Types

type Auto

type Auto struct {
	Next plugin.Handler
	*Zones
	// contains filtered or unexported fields
}

Auto holds the zones and the loader configuration for automatically loading zones.

func (Auto) Name

func (a Auto) Name() string

Name implements the Handler interface.

func (Auto) ServeDNS

func (a Auto) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error)

ServeDNS implements the plugin.Handler interface.

func (Auto) Walk

func (a Auto) Walk() error

Walk will recursively walk of the file under l.directory and adds the one that match l.re.

type Zones

type Zones struct {
	Z map[string]*file.Zone // A map mapping zone (origin) to the Zone's data.

	sync.RWMutex
	// contains filtered or unexported fields
}

Zones maps zone names to a *Zone. This keep track of what we zones we have loaded at any one time.

func (*Zones) Add

func (z *Zones) Add(zo *file.Zone, name string)

Add adds a new zone into z. If zo.NoReload is false, the reload goroutine is started.

func (*Zones) Names

func (z *Zones) Names() []string

Names returns the names from z.

func (*Zones) Origins

func (z *Zones) Origins() []string

Origins returns the origins from z.

func (*Zones) Remove

func (z *Zones) Remove(name string)

Remove removes the zone named name from z. It also stop the the zone's reload goroutine.

func (*Zones) Zones

func (z *Zones) Zones(name string) *file.Zone

Zones returns a zone with origin name from z, nil when not found.