dns

Documentation

Index

• func NewServerDefaults() (*server.Config, error)
• type EndpointsAccessor
  • func NewCachedEndpointsAccessor(endpointsInformer kcoreinformers.EndpointsInformer) (EndpointsAccessor, error)
• type FallbackFunc
• type Server
  • func NewServer(config *server.Config, services ServiceAccessor, endpoints EndpointsAccessor, ...) *Server
  • func (s *Server) ListenAndServe() error
• type ServiceAccessor
  • func NewCachedServiceAccessor(serviceInformer kcoreinformers.ServiceInformer) (ServiceAccessor, error)
• type ServiceResolver
  • func NewServiceResolver(config *server.Config, accessor ServiceAccessor, endpoints EndpointsAccessor, ...) *ServiceResolver
  • func (b *ServiceResolver) Records(dnsName string, exact bool) ([]msg.Service, error)
  • func (b *ServiceResolver) ReverseRecord(name string) (*msg.Service, error)
• type SimpleEndpointsAccessor
  • func (a SimpleEndpointsAccessor) EndpointsByHostnameIP(_ string) ([]*api.Endpoints, error)

Functions

func NewServerDefaults

func NewServerDefaults() (*server.Config, error)

NewServerDefaults returns the default SkyDNS server configuration for a DNS server.

Types

type EndpointsAccessor

type EndpointsAccessor interface {
	kcorelisters.EndpointsLister
	// EndpointsByHostnameIP retrieves the Endpoints object containing a hostname
	// that resolves to IP. Only endpoint addresses with a hostname field will match.
	// If this returns an error, the caller should indicate that this may be a
	// deliberately ambiguous response (server decided not to support this call.
	EndpointsByHostnameIP(ip string) ([]*api.Endpoints, error)
}

EndpointsAccessor is the interface used by the ServiceResolver to access endpoints.

func NewCachedEndpointsAccessor

func NewCachedEndpointsAccessor(endpointsInformer kcoreinformers.EndpointsInformer) (EndpointsAccessor, error)

NewCachedEndpointsAccessor returns a service accessor that can answer queries about services. It uses a backing cache to make ClusterIP lookups efficient.

type FallbackFunc

type FallbackFunc func(name string, exact bool) (string, bool)

type Server

type Server struct {
	Config      *server.Config
	Services    ServiceAccessor
	Endpoints   EndpointsAccessor
	MetricsName string

	Stop chan struct{}
}

func NewServer

func NewServer(config *server.Config, services ServiceAccessor, endpoints EndpointsAccessor, metricsName string) *Server

NewServer creates a server.

func (*Server) ListenAndServe

func (s *Server) ListenAndServe() error

ListenAndServe starts a DNS server that exposes services and values stored in etcd (if etcdclient is not nil). It will block until the server exits.

type ServiceAccessor

type ServiceAccessor interface {
	kcoreclient.ServicesGetter
	ServiceByClusterIP(ip string) (*api.Service, error)
}

ServiceAccessor is the interface used by the ServiceResolver to access services.

func NewCachedServiceAccessor

func NewCachedServiceAccessor(serviceInformer kcoreinformers.ServiceInformer) (ServiceAccessor, error)

NewCachedServiceAccessor returns a service accessor that can answer queries about services. It uses a backing cache to make ClusterIP lookups efficient.

type ServiceResolver

type ServiceResolver struct {
	// contains filtered or unexported fields
}

ServiceResolver is a SkyDNS backend that will serve lookups for DNS entries based on Kubernetes service entries. The default DNS name for each service will be `<name>.<namespace>.<base>` where base can be an arbitrary depth DNS suffix. Queries not recognized within this base will return an error.

func NewServiceResolver

func NewServiceResolver(config *server.Config, accessor ServiceAccessor, endpoints EndpointsAccessor, fn FallbackFunc) *ServiceResolver

NewServiceResolver creates an object that will return DNS record entries for SkyDNS based on service names.

func (*ServiceResolver) Records

func (b *ServiceResolver) Records(dnsName string, exact bool) ([]msg.Service, error)

Records implements the SkyDNS Backend interface and returns standard records for a name.

The standard pattern is <prefix>.<service_name>.<namespace>.(svc|endpoints|pod).<base>

* prefix may be any series of prefix values

• _endpoints is a special prefix that returns the same as <service_name>.<namespace>.svc.<base>

* service_name and namespace must locate a real service

• unless a fallback is defined, in which case the fallback name will be looked up

* svc indicates standard service rules apply (clusterIP or endpoints as A records)

• reverse lookup of IP is only possible for clusterIP
• SRV records are returned for each host+port combination as: _<port_name>._<port_protocol>.<dns> _<port_name>.<endpoint_id>.<dns>

* endpoints always returns each individual endpoint as A records

• SRV records for endpoints are similar to SVC, but are prefixed with a single label that is a hash of the endpoint IP

* pods is of the form <IP_with_dashes>.<namespace>.pod.<base> and resolves to <IP>

func (*ServiceResolver) ReverseRecord

func (b *ServiceResolver) ReverseRecord(name string) (*msg.Service, error)

ReverseRecord implements the SkyDNS Backend interface and returns standard records for a name.

type SimpleEndpointsAccessor

type SimpleEndpointsAccessor struct {
	kcorelisters.EndpointsLister
}

SimpleEndpointsAccessor answers endpoint lookups but always returns an error for EndpointsByHostnameIP.

func (SimpleEndpointsAccessor) EndpointsByHostnameIP

func (a SimpleEndpointsAccessor) EndpointsByHostnameIP(_ string) ([]*api.Endpoints, error)

EndpointsByHostnameIP always returns an error.