Add a page on how to remove a server from the cluster on AWS

modules/ROOT/content-nav.adoc

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 ** xref:cloud-deployments/neo4j-aws.adoc[]
 ** xref:cloud-deployments/neo4j-gcp.adoc[]
 ** xref:cloud-deployments/neo4j-azure.adoc[]
+** xref:cloud-deployments/neo4j-cluster-cloud.adoc[]
 
 * xref:docker/index.adoc[]
 ** xref:docker/introduction.adoc[]

modules/ROOT/pages/cloud-deployments/neo4j-cluster-cloud.adoc

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+:description: Tha page describes how to manage the Neo4j cluster on AWS.
+:page-role: enterprise-edition
+
+[[neo4j-cluster-cloud-deployments]]
+= Neo4j cluster in self-managed cloud deployments
+
+Before diving into the topic, it is important to understand basics about Neo4j's clustering.
+
+Neo4j cluster consists of a homogenous pool of servers that collectively run a number of databases.
+The servers can operate in two different database-hosting modes: _primary_ and _secondary_.
+A server can simultaneously act as a primary host for one or more databases and as a secondary host for other databases.
+
+For more details on operational and application aspects of Neo4j's clustering, refer to the xref::clustering/index.adoc[Clustering in Neo4j].
+
+For information on how to manage databases and servers in a cluster, see respectively xref::clustering/databases.adoc[] and xref::clustering/servers.adoc[].
+
+
+== Neo4j cluster on AWS
+
+Neo4j does not provide Amazon Machine Images (AMIs) with a pre-installed version of the product.
+The Neo4j AWS Marketplace listings (and listings on GitHub) use CloudFormation templates that deploy and configure Neo4j dynamically with a shell script.
+
+
+// === Neo4j cluster and auto-scaling groups on AWS
+
+
+=== Remove a server from the Neo4j cluster
+
+Rolling updates on Amazon Machine Images (AMIs) often involve their rotating.
+However, simply removing Neo4j servers from the target Network Load Balancer (NLB) one by one does not prevent requests from being routed to them.
+This occurs because the NLB and Neo4j server-side routing operate independently and do not share awareness of a server availability.
+
+To correctly remove a server from the cluster and reintroduce it after the update, follow the steps outlined below:
+
+. Remove the server from the AWS NLB.
+ This prevents external clients from sending requests to the server.
+
+. Since Neo4j's cluster routing (server-side routing) does not use the NLB, you need to ensure that queries are not routed to the server.
+To do this, you have to cleanly shut down the server.
+
+.. Run the following query to check servers are hosting all their assigned databases.
+The query should return no results:
++
+[source, cypher, role=noplay]
+----
+SHOW SERVERS YIELD name, hosting, requestedHosting, serverId WHERE requestedHosting <> hosting
+----
+
+.. Use the following query to check all databases are in their expected state.
+The query should return no results:
++
+[source, cypher, role=noplay]
+----
+SHOW DATABASES YIELD name, address, currentStatus, requestedStatus, statusMessage WHERE currentStatus <> requestedStatus RETURN name, address, currentStatus, requestedStatus, statusMessage
+----
+
+.. To stop the Neo4j service, run the following command:
++
+[source, shell, role=copy]
+----
+sudo systemctl stop neo4j
+----
++
+To configure the timeout period for waiting on active transactions to either complete or be terminated before the shutdown, modify the setting xref::configuration/configuration-settings.adoc#config_db.shutdown_transaction_end_timeout[`db.shutdown_transaction_end_timeout`] in the _neo4j.conf_ file.
+`db.shutdown_transaction_end_timeout` defaults to 10 seconds.
++
+The environment variable `NEO4J_SHUTDOWN_TIMEOUT` determines how long the system will wait for Neo4j to stop before forcefully terminating the process.
+You can change this using `systemctl edit neo4j.service`.
+By default, `NEO4J_SHUTDOWN_TIMEOUT` is set to 120 seconds.
+If the shutdown process exceeds this limit, it is considered failed.
+You may need to increase the value if the system serves long-running transactions.
+
+.. Verify that the shutdown process has finished successfully by checking the _neo4j.log_ for relevant log messages confirming the shutdown.
+
+
+. When everything is updated or fixed, start the servers one by one again.
+.. Run `systemctl start neo4j`.
+.. Once the server has been restarted, confirm it is running successfully.
++
+Run the following command and check the server has state `Enabled` and health `Available`.
++
+[source, cypher, role=noplay]
+----
+SHOW SERVERS WHERE name = [server-id];
+----
+
+.. Confirm that the server has started all the databases that it should.
++
+This command shows any databases that are not in their expected state:
++
+[source, cypher, role=noplay]
+----
+SHOW DATABASES YIELD name, address, currentStatus, requestedStatus, serverID WHERE currentStatus <> requestedStatus AND serverID = [server-id] RETURN name, address, currentStatus, requestedStatus
+----
+
+. Reattach the server to the NLB.
+Once the server is stable and caught up, add it back to the AWS NLB target group.
+
+