dns

Documentation

Index

• func ListenAndServe(config *server.Config, client *client.Client, etcdclient *etcd.Client) error
• func NewServerDefaults() (*server.Config, error)
• type FallbackFunc
• type ServiceAccessor
  • func NewCachedServiceAccessor(client *client.Client, stopCh <-chan struct{}) ServiceAccessor
• type ServiceResolver
  • func NewServiceResolver(config *server.Config, accessor ServiceAccessor, ...) *ServiceResolver
  • func (b *ServiceResolver) Records(dnsName string, exact bool) ([]msg.Service, error)
  • func (b *ServiceResolver) ReverseRecord(name string) (*msg.Service, error)

Functions

func ListenAndServe

func ListenAndServe(config *server.Config, client *client.Client, etcdclient *etcd.Client) 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. TODO: hoist the service accessor out of this package so it can be reused.

func NewServerDefaults

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

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

Types

type FallbackFunc

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

type ServiceAccessor

type ServiceAccessor interface {
	client.ServicesNamespacer
	ServiceByPortalIP(ip string) (*api.Service, error)
}

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

func NewCachedServiceAccessor

func NewCachedServiceAccessor(client *client.Client, stopCh <-chan struct{}) ServiceAccessor

NewCachedServiceAccessor returns a service accessor that can answer queries about services. It uses a backing cache to make PortalIP 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 kclient.EndpointsNamespacer, 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 (portalIP or endpoints as A records)

• reverse lookup of IP is only possible for portalIP
• 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.