kubenodes

Name

kubenodes - creates records for Kubernetes nodes.

Description

kubenodes watches the Kubernetes API and synthesizes A, AAAA, and PTR records for InternalIPs of Nodes.

This plugin can only be used once per Server Block.

Syntax

kubenodes [ZONES...] {
    endpoint URL
    tls CERT KEY CACERT
    kubeconfig KUBECONFIG [CONTEXT]
    ttl TTL
    fallthrough [ZONES...]
}

• endpoint specifies the URL for a remote k8s API endpoint. If omitted, it will connect to k8s in-cluster using the cluster service account.
• tls CERT KEY CACERT are the TLS cert, key and the CA cert file names for remote k8s connection. This option is ignored if connecting in-cluster (i.e. endpoint is not specified).
• kubeconfig KUBECONFIG [CONTEXT] authenticates the connection to a remote k8s cluster using a kubeconfig file. [CONTEXT] is optional, if not set, then the current context specified in kubeconfig will be used. It supports TLS, username and password, or token-based authentication. This option is ignored if connecting in-cluster (i.e., the endpoint is not specified).
• 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. It will need to be positioned before the kubernetes plugin if kubenode is using the same zone or a superzone of kubernetes.

Ready

This plugin reports that it is ready to the ready plugin once it has synced to the Kubernetes API.

Examples

Answer forward and reverse lookups for nodes under the zone node.cluster.local.. Fallthrough to next plugin for reverse lookups that don't match any Nodes' InternalIPs.

kubenodes node.cluster.local in-addr.arpa ip6.arpa {
  fallthrough in-addr.arpa ip6.arpa
}