External DNS requires the system-name, site-domain, and can-external-dns values that are defined with the csi config init command. These values are used to customize the External DNS configuration during installation.
The system-name and site-domain values specified as part of the csi config init are used together in the system-name.site-domain format, creating the external domain for external hostnames for services accessible from the Customer Access Network (CAN). Changing this value requires updating all impacted external-dns.alpha.kubernetes.io/hostname annotations, VirtualService and possibly Gateway objects, the CoreDNS configmap, Keycloak settings for valid OAuth callback URLs, Keycloak gatekeeper configuration, and generating new certificates.
Warning: Changing the system-name.site-domain value post-installation is not recommended because of the complexity of changes required.
Input for csi config init:
--system-name testsystem
--site-domain example.com
The can-external-dns value is the IP address that DNS queries under the combined system-name.site-domain values need to be delegated.
This will be the shared IP address for services/cray-externaldns-coredns-tcp and services/cray-externaldns-coredns-udp services, which must be an IP address in the customer_access_static_metallb_address_pool subnet defined in the csi config init input. See Customer Access Network (CAN) for more information.
Changing this value requires updating the loadBalancerIP value of the services/cray-externaldns-coredns-tcp and services/cray-externaldns-coredns-udp services.
Input for csi config init:
--can-external-dns 10.102.5.30
This input is the CAN IP address for resolution of system services.