Task

By default, DNS query logging is disabled in CoreDNS, this article details the steps to enable query logging for CoreDNS in a Kubernetes cluster provisioned by the Rancher Kubernetes Engine (RKE) CLI or Rancher v2.x.

Pre-requisites

• A Kubernetes cluster provisioned by the Rancher Kubernetes Engine (RKE) CLI or Rancher v2.x, using the CoreDNS dns add-on.

Steps

To enable DNS query logging the log plugin needs to be configured, by addition of log to the Corefile in the coredns ConfigMap of the kube-system Namespace.

For example, to use the default log plugin configuration and log all queries, the Corefile definition would be updated as follows:

.:53 {
    log
    errors
    health
    ready
    kubernetes cluster.local in-addr.arpa ip6.arpa {
      pods insecure
      fallthrough in-addr.arpa ip6.arpa
    }
    prometheus :9153
    forward . "/etc/resolv.conf" {
      policy random
    }
    cache 30
    loop
    reload
    loadbalance
}

Steps to update the CoreDNS ConfigMap and persist these changes can be found in the article "How to update the CoreDNS ConfigMap in a Rancher Kubernetes Engine (RKE) CLI or Rancher v2.x provisioned Kubernetes cluster".

For the full list of available options when configuring the log plugin refer to the plugin documentation.

Further reading

• CoreDNS log plugin documentation