K8s: OSS Cluster API limitation (#1670)

* OSS Cluster API limitation

* Update content/operate/kubernetes/networking/_index.md

Co-authored-by: andy-stark-redis <164213578+andy-stark-redis@users.noreply.github.com>

* Update content/operate/kubernetes/networking/_index.md

---------

Co-authored-by: andy-stark-redis <164213578+andy-stark-redis@users.noreply.github.com>

Author: kaitlynmichael

content/operate/kubernetes/networking/_index.md

@@ -26,16 +26,22 @@ Redis Enterprise supports three [types of services](https://kubernetes.io/docs/c
 
 By default, the operator creates a `ClusterIP` type service, which exposes a cluster-internal IP and that can only be accessed from within the K8s cluster. For requests to be routed from outside the K8s cluster, you need an [Ingress](https://kubernetes.io/docs/concepts/services-networking/ingress/) (or [route](https://docs.openshift.com/container-platform/4.12/networking/routes/route-configuration.html) if you are using OpenShift). See [kubernetes.io](https://kubernetes.io/docs/) for more details on [Ingress](https://kubernetes.io/docs/concepts/services-networking/ingress/) and [Ingress controllers](https://kubernetes.io/docs/concepts/services-networking/ingress-controllers/).
 
-* To use NGINX or HAProxy Ingress controllers, see [Ingress routing]({{< relref "/operate/kubernetes/networking/ingress" >}}).
-* To use OpenShift routes, see [OpenShift routes]({{< relref "/operate/kubernetes/networking/routes" >}}).
-* To use Istio as an Ingress controller, see [Istio Ingress routing]({{< relref "/operate/kubernetes/networking/istio-ingress" >}})
+- To use NGINX or HAProxy Ingress controllers, see [Ingress routing]({{< relref "/operate/kubernetes/networking/ingress" >}}).
+- To use OpenShift routes, see [OpenShift routes]({{< relref "/operate/kubernetes/networking/routes" >}}).
+- To use Istio as an Ingress controller, see [Istio Ingress routing]({{< relref "/operate/kubernetes/networking/istio-ingress" >}})
 
 ## `ingressOrRouteSpec` for Active-Active databases
 
 Versions 6.4.2 or later of Redis Enterprise for Kubernetes include a feature for ingress configuration. The `ingressOrRouteSpec` field is available in the RedisEnterpriseCluster spec to automatically create an Ingress (or route) for the API service and databases (REAADB) on that REC. See [REC external routing]({{< relref "/operate/kubernetes/networking/ingressorroutespec" >}}) for more details.
 
 This feature only supports automatic Ingress creation for Active-Active databases created and managed with the RedisEnterpriseActiveActiveDatabase (REAADB) custom resource. Use with the standard Redis Enterprise database (REDB) is not currently supported.
 
+## OSS Cluster API limitations
+
+When using [OSS Cluster API]({{< relref "/operate/rs/databases/configure/oss-cluster-api" >}}), clients must specify the IP addresses of Redis instances to perform operations. Since Pod IP addresses are internal to the Kubernetes cluster and not publicly accessible, **OSS Cluster API can only be used by clients running on pods within the same Kubernetes cluster as the Redis Enterprise pods.** Using OSS Cluster API from outside the Kubernetes cluster is not tested and currently not supported.
+
+For applications that need to access Redis databases from outside the Kubernetes cluster, use standard Redis Enterprise connectivity methods with the external routing options described above (Ingress controllers, load balancers, or OpenShift routes). These methods do not support OSS Cluster API but provide reliable external access to your Redis databases.
+
 ## REC domain name
 
 The RedisEnterpriseCluster does not support custom domain names. Domain names for the REC are in the following format: `<rec-name>.<namespace>.svc.cluster.local`.