REDB info

Author: kaitlynmichael

content/operate/kubernetes/architecture/_index.md

@@ -43,10 +43,20 @@ For settings managed by the operator, any changes made outside of the CR YAML fi
 
 ## RedisEnterpriseCluster REC
 
-## RedisEnterpriseDatabase REDB
+A Redis Enterprise cluster is a set of Redis Enterprise nodes pooling resources. Each node is capable of running multiple Redis instances (shards). A Redis cluster is created an managed by the RedisEnterpriseCluster (REC) custom resource. Changes to the REC YAML configuration prompt the operator to make changes to the cluster.
 
 {{< image filename="/images/k8s/k8s-node-arch.png">}}
 
+The REC is required for both standard databases (REDB) and Active-Active databases (REAADB).
+
+## RedisEnterpriseDatabase REDB
+
+A Redis Enterprise database is a logical entity that manages your entire dataset across multiple Redis instances (shards). A Redis instance is a single-threaded database process (commonly referred to as a shard).
+
+Redis databases are created and managed by the RedisEnterpriseDatabase (REDB)custom resource. Changes to the REDB YAML configuration file prompt the operator to make changes to the database. See the [RedisEnterpriseDatabase (REDB) API Reference]({{<relref "/operate/kubernetes/reference/redis_enterprise_database_api">}}) for a full list of fields and settings.
+
+A database can be managed by an operator in the same namespace, or a different namespace. See []"Flexible deployment"]({{<relref "/operate/kubernetes/architecture/deployment-options">}}) options and []"Manage databases in multiple namespaces"]({{<relref "/operate/kubernetes/re-clusters/multi-namespace">}}) for more information.
+
 ## Active-Active databases
 
 ### RedisEnterpriseRemoteCluster RERC
@@ -63,5 +73,7 @@ secrets
 
 PVCs, network attached
 
+## Networking
+
 ## Metrics