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Author: mwlinca

modules/cnf-best-practices-application-dns-configuration-requirements.adoc

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+[id="cnf-best-practices-application-dns-configuration-requirements"]
+[id="application-dns-configuration-requirements"]
+= Application DNS configuration requirements
+
+CNFs should use the service name only as a configuration parameter for attaching to a service within your namespace, the cluster will append namespace name and kubernetes service nomenclature on behalf of the application via search string in DNS. This allows a generic name for a service that works in all clusters no matter what the namespace name is and what the cluster base FQDN is.
+
+.Example
+[source,terminal]
+----
+search clspcoykvzwcscp-y-xx-w1-001.svc.cluster.local
+svc.cluster.local cluster.local kub2-4.csp-1.vzwops.com
+nameserver 198.223.0.10
+options ndots:5
+----
+
+If an application deploys a service in the namespace `clspcoykvzwcscp-y-xx-w1-001` and is attempting to access a service named `worker`, the application should just configure the client of the service with an FQDN of `worker`.
+
+The DNS search suffix will append `clspcoykvzwcscp-y-xx-w1-001.svc.cluster.local` to the end of the name and result in a successful query for `worker.clspcoykvzwcscp-y-xx-w1-001.svc.cluster.local`. This allows an application to be less aware of the application's namespace name and genericize the configuration of the application.
+
+.VCP CNF requirement - Doors Id 94182
+[IMPORTANT]
+====
+CNFs must use the service name only as a configuration parameter for attaching to a service within your namespace
+====
+
+.VCP CNF requirement - Doors Id 94183
+[IMPORTANT]
+====
+For FQDNs that are outside of their namespace (in another cluster or in the same cluster), applications must append a . at the end of the FQDN so as not to trigger search strings for the FQDN
+====
+
+.Example
+[source,terminal]
+----
+nnrfe1-000.bbtpnj33.ne.nrf.5gc.vzims.com
+clspcoykvzwcscp-y-xx-w1-001-scp-cache-headless.clspcoykvzwcscp-y-xx-w1-001.svc.cluster.local
+----
+
+For more information, see link:https://kubernetes.io/docs/concepts/services-networking/dns-pod-service[Kubernetes upstream reference for pod/service names and DNS].