Add notes on disabling persistent storage to kafka and logging chart
docs

Change-Id: I1cb6e6af61e664264b99789c6f9b5baf36593077
diff --git a/charts/kafka.md b/charts/kafka.md
index 30d43ea..5d9b35e 100644
--- a/charts/kafka.md
+++ b/charts/kafka.md
@@ -1,12 +1,38 @@
 # Kafka Helm chart
 
-The *kafka* helm chart is not maintained by CORD, but it is available online at: <https://github.com/kubernetes/charts/tree/master/incubator/kafka>
+The *kafka* helm chart is not maintained by CORD, but it is available online
+at: <https://github.com/kubernetes/charts/tree/master/incubator/kafka>
 
-To install kafka using the *cord-kafka* name, run the following commands:
+To install kafka using the `cord-kafka` name, create a YAML values file to
+configure Kafka (for developers, this is in
+`helm-charts/example/kafka-single.yaml`):
+
+```yaml
+---
+# Deploy a single replica of Kafka during development
+
+# configuration ref: https://kafka.apache.org/documentation/#configuration
+configurationOverrides:
+  "offsets.topic.replication.factor": 1
+  "log.retention.hours": 4
+  "log.message.timestamp.type": "LogAppendTime"
+
+replicas: 1
+
+persistence:
+  enabled: false
+
+zookeeper:
+  replicaCount: 1
+  persistence:
+    enabled: false
+```
+
+Then run the following commands to start Kafka:
 
 ```shell
 helm repo add incubator http://storage.googleapis.com/kubernetes-charts-incubator
-helm install -f examples/kafka-single.yaml --version 0.8.8 -n cord-kafka incubator/kafka
+helm install -f kafka-single.yaml --version 0.8.8 -n cord-kafka incubator/kafka
 ```
 
 > NOTE: Historically there were two kafka busses deployed (another one named
@@ -18,8 +44,7 @@
 that to listen for events:
 
 ```shell
-cd helm-charts
-helm install -n kafkacat xos-tools/kafkacat
+helm install -n kafkacat cord/kafkacat
 ```
 
 Once the container is up and running you can exec into the pod and run kafkacat
diff --git a/charts/logging-monitoring.md b/charts/logging-monitoring.md
index a051500..ad30bb3 100644
--- a/charts/logging-monitoring.md
+++ b/charts/logging-monitoring.md
@@ -29,13 +29,50 @@
 
 ## logging charts
 
+By default, the logging charts rely on the [Persistent Storage](storage.md)
+charts to provide a persistent ElasticSearch database.  You must install those
+first before running the `logging` chart.
+
+In development scenarios where persistence isn't required, it can be disabled
+by using the following values file (if developing, this is located in
+`helm-charts/examples/logging-single.yaml`):
+
+```yaml
+---
+# For development and testing logging, don't persist data and
+# run a minimum number of instances of elasticsearch components
+
+elasticsearch:
+
+  cluster:
+    env:
+      MINIMUM_MASTER_NODES: "1"
+
+  client:
+    replicas: 1
+
+  master:
+    replicas: 2
+    persistence:
+      enabled: false
+
+  data:
+    replicas: 1
+    persistence:
+      enabled: false
+```
+
+Then either install the logging chart with persistent storage:
+
 ```shell
 helm install -n logging cord/logging
 ```
 
-For smaller developer/test environments without persistent storage, please use
-the *examples/logging-single.yaml* file to run the logging chart, which doesn't
-create PVC's.
+Or without:
+
+```shell
+helm install -f logging-single.yaml -n logging cord/logging
+```
 
 ### Logging Dashboard