[[_standalone-ha-mode]]

=== Standalone Clustered Mode

Standalone clustered operation mode is for when you want to run {{book.project.name}} within a cluster.  This mode
requires that you have a copy of each distribution for each node you want to run in the cluster.  While very easy to
deploy initially, this mode can become cumbersome if you end up having a large cluster because you will have to
modify the configuration in each node anytime you need to make a change.

==== Standalone Clustered Configuration

The distribution has a mostly pre-configured app server configuration file for running within a cluster.  It has all the specific
infrasture settings you need to configure networking, databases, caches, and discovery.  This file resides
in _.../standalone/configuration/standalone-ha.xml_.  There's a few things missing from this configuration.
You can't run {{book.project.name}} in a cluster without a configuring a shared database connection.  You also need to
deploy some type of load balancer in front of the cluster.  The <<fake/../../clustering.adoc#_clustering,clustering>> and
<<fake/../../database.adoc#_database,database>> sections of this guide walk you though these things.

.Standalone HA Config
image:../../{{book.images}}/standalone-ha-config-file.png[]

NOTE: Any changes you make to this file while the server is running will not take effect and may even be overwritten
      by the server.  Instead use the the command line scripting or the web console of {{book.appserver.name}}.  See
      the link:{{book.appserver.admindoc.link}}[{{book.appserver.admindoc.name}}] for more information.

==== Standalone Boot Script

You use the same boot scripts to start {{book.project.name}} as you do in standalone mode.  The difference is that
you pass in an additional flag to point to the HA config file.

.Standalone Clustered Boot Scripts
image:../../{{book.images}}/standalone-boot-files.png[]

To boot the server:

.Linux/Unix
[source]
----
$ .../bin/standalone.sh --server-config=standalone-ha.xml
----

.Windows
[source]
----
> ...\bin\standalone.bat --server-config=standalone-ha.xml
----

==== Standalone Clustered {{book.project.name}} JSON Configuration

The {{book.project.name}} specific json configure file resides in the same place as in standalone mode: _.../standalone/configuration/keycloak.json_.
Like _standalone-ha.xml_ you have to modify this file in each distribution in your cluster in order for changes to take effect.

NOTE: Any changes you make to this file while the server is running will not take effect.  You'll need to reboot the
      server.