[DOCS] Enroll additional nodes on Docker (#81787)

* [DOCS] Enroll additional nodes on Docker

* Remove -p option for second node

Co-authored-by: Fabio Busatto <52658645+bytebilly@users.noreply.github.com>

* Rename nodes to align with other Docker docs

* Add elastic network to first node docker run command

* Remove hyphen from node names

Co-authored-by: Fabio Busatto <52658645+bytebilly@users.noreply.github.com>

docs/reference/setup/install/docker.asciidoc

@@ -82,7 +82,7 @@ output to the terminal, plus an enrollment token for enrolling {kib}.
 ifeval::["{release-state}"!="unreleased"]
 [source,sh,subs="attributes"]
 ----
-docker run --name es-node01 -p 9200:9200 -p 9300:9300 -it {docker-image}
+docker run --name es01 --net elastic -p 9200:9200 -p 9300:9300 -it {docker-image}
 ----
 
 endif::[]
@@ -103,7 +103,7 @@ For example:
 
 [source,sh]
 ----
-docker exec -it es-node01 /usr/share/elasticsearch/bin/elasticsearch-reset-password
+docker exec -it es01 /usr/share/elasticsearch/bin/elasticsearch-reset-password
 ----
 ====
 
@@ -112,7 +112,7 @@ your local machine.
 +
 [source,sh]
 ----
-docker cp es-node01:/usr/share/elasticsearch/config/tls_auto_config_*/http_ca.crt .
+docker cp es01:/usr/share/elasticsearch/config/tls_auto_config_*/http_ca.crt .
 ----
 
 . Open a new terminal and verify that you can connect to your {es} cluster by
@@ -125,6 +125,55 @@ curl --cacert http_ca.crt -u elastic https://localhost:9200
 ----
 // NOTCONSOLE
 
+==== Enroll additional nodes
+
+When you start {es} for the first time, the installation process configures a single-node cluster by default. This process also generates an enrollment token
+and prints it to your terminal. If you want a node to join an existing cluster,
+start the new node with the generated enrollment token.
+
+--
+.Generating enrollment tokens
+****
+The enrollment token is valid for 30 minutes. If you need to generate a 
+new enrollment token, run the
+<<create-enrollment-token,`elasticsearch-create-enrollment-token`>> tool on your
+existing node. This tool is available in the {es} `bin` directory of the Docker 
+container.
+
+For example, run the following command on the existing `es01` node to
+generate an enrollment token for new {es} nodes:
+
+[source,sh]
+----
+docker exec -it es01 /usr/share/elasticsearch/bin/elasticsearch-create-enrollment-token -s node
+----
+****
+--
+
+. In the terminal where you started your first node, copy the generated
+enrollment token for adding new {es} nodes. 
+
+. On your new node, start {es} and include the generated enrollment token.
++
+[source,sh,subs="attributes"]
+----
+docker run -e ENROLLMENT_TOKEN="<token>" --name es02 --net elastic -it docker.elastic.co/elasticsearch/elasticsearch:{docker-image}
+----
++
+{es} is now configured to join the existing cluster.
+
+If you experience issues where the container where your first node is running
+exits when your second node starts, explicitly set values for the JVM heap size.
+To <<set-jvm-heap-size,manually configure the heap size>>, include the
+`ES_JAVA_OPTS` variable and set values for `-Xms` and `-Xmx` when starting each
+node. For example, the following command starts node `es02` and sets the
+minimum and maximum JVM heap size to 1 GB:
+
+[source,sh,subs="attributes"]
+----
+docker run -e ES_JAVA_OPTS="-Xms1g -Xmx1g" -e ENROLLMENT_TOKEN="<token>" --name es02 -p 9201:9200 --net elastic -it docker.elastic.co/elasticsearch/elasticsearch:{docker-image}
+----
+
 ===== Next steps
 
 You now have a test {es} environment set up. Before you start