How To Update CoreDNS's Resolver Policy
This document (000020186) is provided subject to the disclaimer at the end of this document.
Situation
Task
This article outlines how to change CoreDNS's forward resolver policy.
Pre-requisites
A custom cluster provisioned by Rancher or RKE with CoreDNS.
The CoreDNS docs explain the various configurations. In this case, we are concerned with the policy. Which defaults to random
.
Resolution
To change the policy to sequential
, edit your clusters yaml. For RKE provisioned clusters this will be your cluster.yaml
and for Rancher provisioned custom clusters this will be found by editing the cluster.
For RKE add the following to the end of the file, but for Rancher provisioned clusters, nest this in the rancher_kubernetes_engine_config
section.
addons: |-
---
apiVersion: v1
kind: ConfigMap
metadata:
name: coredns
namespace: kube-system
data:
Corefile: |
.:53 {
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 sequential
}
cache 30
loop
reload
loadbalance
}
The lines of note here are the following, which are changed from just forward . "/etc/resolv.conf"
.
forward . "/etc/resolv.conf" {
policy sequential
}
At this point you should be able to just hit save in Rancher or run rke up
and the change will be pushed to the cluster.
Disclaimer
This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.
- Document ID:000020186
- Creation Date: 06-May-2021
- Modified Date:06-May-2021
-
- SUSE Rancher
For questions or concerns with the SUSE Knowledgebase please contact: tidfeedback[at]suse.com