7.5. Troubleshooting CoreDNS

This section offers troubleshooting information related to DNS resolution in the K3s cluster.

If both /etc/resolv.conf and /run/systemd/resolve/resolv.conf (files used to list the IP address of DNS servers) contain loopback addresses, CoreDNS (a component of the K3s Kubernetes cluster that handles DNS resolution) will not work properly 1. If configure-dns (a script called by install-k3s) detects this situation, you will see a warning message and the following prompt 2:

IP address(es) of DNS resolvers, separated by ';'

Enter a semicolon-separated list of DNS server IP addresses that are not loopback addresses. A suggested default will be offered to you in square brackets, consisting of non-loopback addresses collected from your machine's resolv.conf files; you can simply hit Enter to accept the suggested default.


If the DNS settings of your system change after K3s is initially installed (for example if DNS servers are added or removed), run this command in the lockss user's lockss-installer directory as a privileged user who can become root via sudo 3:






See Installing K3s.


See Running Commands as a Privileged User.