Use the Liberty profile server command
to start and stop WebSphere® eXtreme Scale servers
in the Liberty profile.
Before you begin
The Liberty profile is
the Java virtual machine (JVM) process that starts in OSGi and provides
a flexible framework for serving applications. The eXtreme Scale server is the mechanism
that provides grid services. The main two services are the catalog
service and the container service. A Liberty profile is started from
the command line with the server start server_name or server
run server_name commands. When the Liberty profile starts, it reads
the server.xml file to determine what Liberty profile features to start.
WebSphere eXtreme Scale has three features:
server, client, and web. If you add the server feature to the feature
manager, then the Liberty profile starts
the eXtreme Scale server bundles.
However, adding the server feature does not necessarily start any eXtreme Scale servers.
The eXtreme Scale servers start only
when a valid service is configured. For example, if you want to configure
a catalog service, then the isCatalog="true" attribute
must be set on the xsServer ... element in the server.xml file.
The
following options are available to configure a container service:
- Copy a valid objectgrid.xml file (with or
without an accompanying objectGridDeployment.xml file)
into the wlp_home/usr/servers/server_name/grids directory.
This grids directory is a monitored directory,
and changes to files in this directory initiate events in the Liberty profile runtime environment. For example, when
new objectgrid.xml, objectGridDeployment.xml, or both
files are found, eXtreme Scale creates
and starts a new container. When one of these files are deleted, eXtreme Scale stops that container.
When files are modified, eXtreme Scale stops
and restarts the container. Multiple containers can exist in the same eXtreme Scale server, which requires
that subdirectories exist inside the grids directory.
- Install an OSGi bundle.
This bundle must reference a blueprint.xml file
that contains server metadata. This method of starting a server is
similar to how you can start servers OSGi environments without the Liberty profile in WebSphere eXtreme Scale Version 7.1.1. In Version
8.5, the server element is no longer required in the blueprint.xml file.
Therefore, you must define the server metadata in the server.xml file.
Additionally, bundles are simple to install and start by dropping
them into the grids directory in a similar way
that you drop XML files in the grids directory.
- Use the embedded server API.
This option is similar to the process for starting the server in a
stand-alone environment. With the Liberty profile, however, you
must ensure that you run your code to start the eXtreme Scale server.
About this task
Use this task to start
eXtreme Scale servers with the
Liberty profile server command.
The
wlp/bin directory contains a script called
server to
help control the server process. The following syntax for this command
is supported:
server <task> [server] [options]
Procedure