Update the cmn-external-dns value post-installation

By default, the services/cray-dns-powerdns-cmn-tcp and services/cray-dns-powerdns-cmn-udp services both share the same Customer Management Network (CMN) external IP address. This is defined by the cmn-external-dns value, which is specified during the csi config init input.

The IP address must be in the static range reserved in MetalLB’s cmn-static-pool subnet. Currently, this is the only CMN IP address that must be known external to the system, in order for external DNS to delegate the system-name.site-domain zone to services/cray-dns-powerdns deployment.

Changing this value after install is relatively straightforward, and only requires the external IP address for services/cray-dns-powerdns-cmn-tcp and services/cray-dns-powerdns-cmn-udp services to be changed. This procedure will update the IP addresses that DNS queries.

Prerequisites

The system is installed.

Procedure

Update the LoadBalancer IP address

  1. Find the external IP address for the services/cray-dns-powerdns-cmn-tcp and services/cray-dns-powerdns-cmn-tcp services.

    ncn-m001# kubectl -n services get svc | grep cray-dns-powerdns-cmn-

    Example output:

    cray-dns-powerdns-cmn-tcp                     LoadBalancer   10.25.211.48    10.102.14.113   53:31111/TCP                 2d2h
cray-dns-powerdns-cmn-udp                     LoadBalancer   10.25.156.88    10.102.14.113   53:32674/UDP                 2d2h

  2. Edit the services and change spec.loadBalancerIP to the desired CMN IP address.

    1. Edit the cray-dns-powerdns-cmn-tcp service.

      ncn-m001# kubectl -n services edit svc cray-dns-powerdns-cmn-tcp

    2. Edit the cray-dns-powerdns-cmn-udp service.

      ncn-m001# kubectl -n services edit svc cray-dns-powerdns-cmn-udp

Update SLS

The external-dns IP address reservation in the SLS CMN cmn_metallb_static_pool subnet should be updated to the desired CMN IP address.

  1. Retrieve the SLS data for CMN.

    ncn-m001# export TOKEN=$(curl -s -k -S -d grant_type=client_credentials \
              -d client_id=admin-client -d client_secret=`kubectl get secrets admin-client-auth \
              -o jsonpath='{.data.client-secret}' | base64 -d` \
              https://api-gw-service-nmn.local/keycloak/realms/shasta/protocol/openid-connect/token \
            | jq -r '.access_token')

ncn-m001# curl -s -k -H "Authorization: Bearer ${TOKEN}" \
              https://api-gw-service-nmn.local/apis/sls/v1/networks/CMN|jq > CMN.json

ncn-m001# cp CMN.json CMN.json.bak

  2. Update the external-dns IP address in CMN.json to the desired CMN IP address.

    {
  "Comment": "site to system lookups",
  "IPAddress": "x.x.x.x",
  "Name": "external-dns"
}

  3. Upload the updated CMN.json file to SLS.

    ncn-m001# curl -s -k -H "Authorization: Bearer ${TOKEN}" --header \
              "Content-Type: application/json" --request PUT --data @CMN.json \
              https://api-gw-service-nmn.local/apis/sls/v1/networks/CMN

Update customizations.yaml

IMPORTANT: If this step is not performed, then the PowerDNS configuration will be overwritten with the previous value the next time CSM or the cray-dns-powerdns Helm chart is upgraded.

  1. Extract customizations.yaml from the site-init secret in the loftsman namespace.

    ncn-m001# kubectl -n loftsman get secret site-init -o json | jq -r '.data."customizations.yaml"' | base64 -d > customizations.yaml

  2. Update system_to_site_lookups in customizations.yaml to the desired CMN IP address.

    spec:
  network:
    netstaticips:
      site_to_system_lookups: x.x.x.x

  3. Update the site-init secret in the loftsman namespace.

    ncn-m001# kubectl delete secret -n loftsman site-init
ncn-m001# kubectl create secret -n loftsman generic site-init --from-file=customizations.yaml