README ¶
etcd
etcd enables reading zone data from an etcd instance. The data in etcd has to be encoded as a message like SkyDNS. It should also work just like SkyDNS.
The etcd plugin makes extensive use of the proxy plugin to forward and query other servers in the network.
Syntax
etcd [ZONES...]
- ZONES zones etcd should be authoritative for.
The path will default to /skydns
the local etcd proxy (http://localhost:2379). If no zones are
specified the block's zone will be used as the zone.
If you want to round robin
A and AAAA responses look at the loadbalance
plugin.
etcd [ZONES...] {
stubzones
fallthrough
path PATH
endpoint ENDPOINT...
upstream ADDRESS...
tls CERT KEY CACERT
}
stubzones
enables the stub zones feature. The stubzone is only done in the etcd tree located under the first zone specified.fallthrough
If zone matches but no record can be generated, pass request to the next plugin.- PATH the path inside etcd. Defaults to "/skydns".
- ENDPOINT the etcd endpoints. Defaults to "http://localhost:2397".
upstream
upstream resolvers to be used resolve external names found in etcd (think CNAMEs) pointing to external names. If you want CoreDNS to act as a proxy for clients, you'll need to add the proxy plugin. ADDRESS can be an IP address, and IP:port or a string pointing to a file that is structured as /etc/resolv.conf.tls
followed by:- no arguments, if the server certificate is signed by a system-installed CA and no client cert is needed
- a single argument that is the CA PEM file, if the server cert is not signed by a system CA and no client cert is needed
- two arguments - path to cert PEM file, the path to private key PEM file - if the server certificate is signed by a system-installed CA and a client certificate is needed
- three arguments - path to cert PEM file, path to client private key PEM file, path to CA PEM file - if the server certificate is not signed by a system-installed CA and client certificate is needed
Examples
This is the default SkyDNS setup, with everying specified in full:
. {
etcd skydns.local {
stubzones
path /skydns
endpoint http://localhost:2379
upstream 8.8.8.8:53 8.8.4.4:53
}
prometheus
cache 160 skydns.local
loadbalance
proxy . 8.8.8.8:53 8.8.4.4:53
}
Or a setup where we use /etc/resolv.conf
as the basis for the proxy and the upstream
when resolving external pointing CNAMEs.
. {
etcd skydns.local {
path /skydns
upstream /etc/resolv.conf
}
cache 160 skydns.local
proxy . /etc/resolv.conf
}
Reverse zones
Reverse zones are supported. You need to make CoreDNS aware of the fact that you are also
authoritative for the reverse. For instance if you want to add the reverse for 10.0.0.0/24, you'll
need to add the zone 0.0.10.in-addr.arpa
to the list of zones. Showing a snippet of a Corefile:
etcd skydns.local 10.0.0.0/24 {
stubzones
...
Next you'll need to populate the zone with reverse records, here we add a reverse for 10.0.0.127 pointing to reverse.skydns.local.
% curl -XPUT http://127.0.0.1:4001/v2/keys/skydns/arpa/in-addr/10/0/0/127 \
-d value='{"host":"reverse.skydns.local."}'
Querying with dig:
% dig @localhost -x 10.0.0.127 +short
reverse.skydns.local.
Documentation ¶
Overview ¶
Package etcd provides the etcd backend plugin.
Index ¶
- type Etcd
- func (e *Etcd) IsNameError(err error) bool
- func (e *Etcd) Lookup(state request.Request, name string, typ uint16) (*dns.Msg, error)
- func (e *Etcd) MinTTL(state request.Request) uint32
- func (e *Etcd) Name() string
- func (e *Etcd) Records(state request.Request, exact bool) ([]msg.Service, error)
- func (e *Etcd) Reverse(state request.Request, exact bool, opt plugin.Options) (services []msg.Service, err error)
- func (e *Etcd) Serial(state request.Request) uint32
- func (e *Etcd) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error)
- func (e *Etcd) Services(state request.Request, exact bool, opt plugin.Options) (services []msg.Service, err error)
- func (e *Etcd) TTL(node *etcdc.Node, serv *msg.Service) uint32
- func (e *Etcd) UpdateStubZones()
- type Stub
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Etcd ¶
type Etcd struct { Next plugin.Handler Fallthrough bool Zones []string PathPrefix string Proxy proxy.Proxy // Proxy for looking up names during the resolution process Client etcdc.KeysAPI Ctx context.Context Stubmap *map[string]proxy.Proxy // list of proxies for stub resolving. // contains filtered or unexported fields }
Etcd is a plugin talks to an etcd cluster.
func (*Etcd) IsNameError ¶
IsNameError implements the ServiceBackend interface.
func (*Etcd) Records ¶
Records looks up records in etcd. If exact is true, it will lookup just this name. This is used when find matches when completing SRV lookups for instance.
func (*Etcd) Reverse ¶
func (e *Etcd) Reverse(state request.Request, exact bool, opt plugin.Options) (services []msg.Service, err error)
Reverse implements the ServiceBackend interface.
func (*Etcd) Services ¶
func (e *Etcd) Services(state request.Request, exact bool, opt plugin.Options) (services []msg.Service, err error)
Services implements the ServiceBackend interface.
func (*Etcd) TTL ¶
TTL returns the smaller of the etcd TTL and the service's TTL. If neither of these are set (have a zero value), a default is used.
func (*Etcd) UpdateStubZones ¶
func (e *Etcd) UpdateStubZones()
UpdateStubZones checks etcd for an update on the stubzones.