kubeLoadBalancer

README

kubeloadbalancer

Name

kubeloadbalancer - create records for Kubernetes LoadBalancer type Services.

Description

kubeloadbalancer synthesizes A, AAAA records for LoadBalancer type Services' LoadBalance addresses.

By default, this plugin requires ...

• The kubeapi plugin to make a connection to the Kubernetes API.
• CoreDNS's Service Account has list/watch permission to the Serivces API.

This plugin can only be used once per Server Block.

Syntax

kubeloadbalancer [ZONES...] {
    ttl TTL
    fallthrough [ZONES...]
}

• ttl allows you to set a custom TTL for responses. The default is 5 seconds. The minimum TTL allowed is 0 seconds, and the maximum is capped at 3600 seconds. Setting TTL to 0 will prevent records from being cached. All endpoint queries and headless service queries will result in an NXDOMAIN.
• fallthrough [ZONES...] If a query for a record in the zones for which the plugin is authoritative results in NXDOMAIN, normally that is what the response will be. However, if you specify this option, the query will instead be passed on down the plugin chain, which can include another plugin to handle the query. If [ZONES...] is omitted, then fallthrough happens for all zones for which the plugin is authoritative. If specific zones are listed (for example in-addr.arpa and ip6.arpa), then only queries for those zones will be subject to fallthrough.

External Plugin

To use this plugin, compile CoreDNS with this plugin added to the plugin.cfg. This plugin also requires the kubeapi plugin, which should be added to the end of plugin.cfg.

Compile Notice:

• Compile CoreDNS with the Dockerfile this project provided. Modify CoreDNS project's .dockerignore file if use this Dockerfile
• Add two plugins in the end of plugin.cfg

  kubeloadbalancer:github.com/chenwyi2/kubeloadbalancer
  kubeapi:github.com/coredns/kubeapi
  

  Can't got get from Bitbucket which is not a valid go pacakge repository

Ready

This plugin reports that it is ready to the ready plugin once it has received the complete list of Pods from the Kubernetes API.

Examples

Use Service's Status.loadbalancer.ingress.ip to answer ServiceName lookups in the zone md-pv.saicmotortest.com..

md-pv.saicmotortest.com:53 {
  ...
  kubeapi {
    kubeconfig kube.config
  }
  kubeloadbalancer 
  ...
}

Documentation

Index

• type KubeLoadBalancer
  • func New(zones []string) *KubeLoadBalancer
  • func (k *KubeLoadBalancer) Name() string
  • func (k *KubeLoadBalancer) Ready() bool
  • func (k *KubeLoadBalancer) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error)

Types

type KubeLoadBalancer

type KubeLoadBalancer struct {
	Next  plugin.Handler
	Zones []string

	Fall fall.F
	// contains filtered or unexported fields
}

func New

func New(zones []string) *KubeLoadBalancer

func (*KubeLoadBalancer) Name

func (k *KubeLoadBalancer) Name() string

Name implements the Handler interface.

func (*KubeLoadBalancer) Ready

func (k *KubeLoadBalancer) Ready() bool

Ready implements the ready.Readiness interface.

func (*KubeLoadBalancer) ServeDNS

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

ServeDNS implements the plugin.Handler interface.