feat: add scripts and examples how to configure clusterbench for sing…

…leton deployment (resolvs clusterbench#504)

README.adoc

@@ -232,14 +232,78 @@ These scripts can be combined to achieve a desired resulting configuration.
 |===
 | Script | Description
 
-| infinispan-session-management-attribute.cli
+| `infinispan-session-management-attribute.cli`
 | Reconfigures the default session manager to use `ATTRIBUTE` granularity.
 
-| infinispan-session-management-offload.cli
+| `infinispan-session-management-offload.cli`
 | Reconfigures the default session manager to use cache `offload`.
 
+| `singleton-deployment-overlay-add.cli`
+| Adds a deployment overlay for the ClusterBench deployment which configures it for singleton deployment.
+
+| `singleton-deployment-overlay-remove.cli`
+| Removes the previously added deployment overlay so that it will no longer operate as a singleton deployment.
+
 |===
 
+.Example: singleton deployment
+[%collapsible]
+====
+Following is a singleton deployment walk-through.
+Start with two local servers already started and with `clusterbench-ee10.ear` deployed.
+First run the provided scripts against both servers:
+
+[code,shell]
+----
+[rhusar@puglia scripts]$ $JBOSS_HOME/bin/jboss-cli.sh --connect --file=singleton-deployment-overlay-add.cli
+[rhusar@puglia scripts]$ $JBOSS_HOME/bin/jboss-cli.sh --connect --controller=localhost:10090 --file=singleton-deployment-overlay-add.cli
+----
+
+The provided script adds a deployment overlay, which configures existing deployment for singleton deployment.
+This is achieved by overlaying a `META-INF/singleton-deployment.xml` file.
+Note that the script automatically redeploys the deployments affected by this overlay.
+
+Now that these have configured both deployments for singleton deployment, observe the server log:
+
+[code]
+----
+10:39:16,287 INFO  [org.wildfly.clustering.singleton.server] (main - 1) WFLYCLSN0003: node2 elected as the singleton provider of the jboss.deployment.unit."clusterbench-ee10.ear".installer service
+10:39:16,287 INFO  [org.wildfly.clustering.singleton.server] (main - 1) WFLYCLSN0001: This node will now operate as the singleton provider of the jboss.deployment.unit."clusterbench-ee10.ear".installer service
+----
+
+We can now verify that only one of the contexts is available:
+
+[code]
+----
+[rhusar@puglia x]$ curl --head http://localhost:8080/clusterbench/
+HTTP/1.1 404 Not Found
+Connection: keep-alive
+Content-Length: 74
+Content-Type: text/html
+Date: Mon, 23 Sep 2024 08:50:28 GMT
+
+[rhusar@puglia x]$ curl --head http://localhost:8180/clusterbench/
+HTTP/1.1 200 OK
+Connection: keep-alive
+Last-Modified: Fri, 03 May 2024 14:27:54 GMT
+Content-Type: text/html
+Content-Length: 1335
+Accept-Ranges: bytes
+Date: Mon, 23 Sep 2024 08:50:29 GMT
+----
+
+Notice that only one of the servers has returned a valid answer.
+
+To undo the changes, run the 'remove' variant of the scripts:
+
+[code,shell]
+----
+[rhusar@puglia scripts]$ $JBOSS_HOME/bin/jboss-cli.sh --connect --file=singleton-deployment-overlay-remove.cli
+[rhusar@puglia scripts]$ $JBOSS_HOME/bin/jboss-cli.sh --connect --controller=localhost:10090 --file=singleton-deployment-overlay-remove.cli
+----
+
+====
+
 == Custom Build Profiles
 
 There a several profiles to test specific scenarios where the standard build needs to be modified.

scripts/singleton-deployment-overlay-add.cli

@@ -0,0 +1,7 @@
+#
+# Copyright The ClusterBench Authors
+# SPDX-License-Identifier: Apache-2.0
+#
+
+# Adds a deployment overlay for the ClusterBench deployment and redeploys
+deployment-overlay add --name=clusterbench-ee10 --deployments=clusterbench-ee10.ear --content=META-INF/singleton-deployment.xml=singleton-deployment.xml --redeploy-affected

scripts/singleton-deployment-overlay-remove.cli

@@ -0,0 +1,7 @@
+#
+# Copyright The ClusterBench Authors
+# SPDX-License-Identifier: Apache-2.0
+#
+
+# Removes the previously added deployment overlay and redeploys
+deployment-overlay remove --name=clusterbench-ee10 --redeploy-affected

scripts/singleton-deployment.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright The ClusterBench Authors
+  ~ SPDX-License-Identifier: Apache-2.0
+  -->
+<singleton-deployment xmlns="urn:jboss:singleton-deployment:1.0"/>