Operator can add and remove ES nodes

Author: mburke5678

logging/efk-logging-elasticsearch.adoc

@@ -29,5 +29,7 @@ include::modules/efk-logging-elasticsearch-persistent-storage-local.adoc[levelof
 
 include::modules/efk-logging-elasticsearch-persistent-storage-empty.adoc[leveloffset=+2]
 
+include::modules/efk-logging-elasticsearch-add-remove.adoc[leveloffset=+1]
+
 include::modules/efk-logging-elasticsearch-exposing.adoc[leveloffset=+1]
 

modules/efk-logging-elasticsearch-add-remove.adoc

@@ -0,0 +1,118 @@
+// Module included in the following assemblies:
+//
+// * logging/efk-logging-elasticsearch.adoc
+
+[id='efk-logging-elasticsearch-add-remove_{context}']
+= Changing the number of Elasticsearch nodes
+
+You can scale the number of nodes in Elasticsearch.
+
+For example, if you want to increase redundancy, and use the `FullRedundancy` or `MultipleRedundancy` policy, you can add additional data nodes to increase the number of shard replicas in your cluster.  
+
+A {product-title} Elasticsearch cluster can contain three node types, or roles:
+
+* *Master*. A master node performs actions across the cluster, such as creating or deleting an index, tracking which nodes are part of the cluster, and deciding which shards to allocate to which nodes. The master node must have access to the the *_data/_* directory. You can create 1 or 3 master nodes.
+* *Data*. A data node is where {product-title} stores Elasticsearch shards.
+* *Client*. A client node routes requests, handles the Elasticsearch reduce phase, and distributes bulk indexing. 
+
+A node can have any combination of these roles.
+
+.Procedure
+
+. To add a node, create a Cluster Logging Custom Resource (CR) to add a number of modes of a specific type:
++
+[source,yaml]
+----
+apiVersion: "logging.openshift.io/v1alpha1"
+kind: "ClusterLogging"
+metadata:
+  name: "clusterlogging"
+...
+nodes:
+  - nodeCount: 2 <1>
+    nodeSpec:
+      resources: {}
+    roles:  <2>
+    - client
+    - data
+    - master
+----
+<1> Specify the number of nodes of this type.
+<2> Specify the type of node.
++
+[NOTE]
+====
+You can create 1 or 3 master nodes.
+====
++
+For example, to scale the data and master nodes:
++
+----
+nodes:
+  - nodeCount: 1
+    nodeSpec:
+      resources: {}
+    roles:
+    - client
+    - data
+    - master
+    storage: {}
+  - nodeCount: 2
+    nodeSpec:
+      resources: {}
+    roles:
+    - data
+    storage: {}
+  - nodeCount: 3
+    nodeSpec:
+      resources: {}
+    roles:
+    - master
+    storage: {}
+----
+
+. To remove a node, create a Cluster Logging Custom Resource (CR) to reduce the number of modes of a specific type:
++
+[source,yaml]
+----
+apiVersion: "logging.openshift.io/v1alpha1"
+kind: "ClusterLogging"
+metadata:
+  name: "clusterlogging"
+...
+nodes:
+  - nodeCount: 2 <1>
+    nodeSpec:
+      resources: {}
+    roles: 
+    - client
+    - data
+    - master
+----
+<1> Specify the number of nodes of this type.
++
+For example, to remove the master nodes added in the previous example, change the `nodeCount` variable for the master node to `1`:
++
+----
+nodes:
+  - nodeCount: 1
+    nodeSpec:
+      resources: {}
+    roles:
+    - client
+    - data
+    - master
+    storage: {}
+  - nodeCount: 2
+    nodeSpec:
+      resources: {}
+    roles:
+    - data
+    storage: {}
+  - nodeCount: 1
+    nodeSpec:
+      resources: {}
+    roles:
+    - master
+    storage: {}
+----