type=page
status=published
title=Administering GlassFish Server Clusters
next=instances.html
prev=nodes.html
~~~~~~
Administering GlassFish Server Clusters
=======================================

[[GSHAG00005]][[gjfom]]


[[administering-glassfish-server-clusters]]
4 Administering GlassFish Server Clusters
-----------------------------------------

A cluster is a collection of GlassFish Server instances that work
together as one logical entity. A cluster provides a runtime environment
for one or more Java Platform, Enterprise Edition (Java EE)
applications. A cluster provides high availability through failure
protection, scalability, and load balancing.

The Group Management Service (GMS) enables instances to participate in a
cluster by detecting changes in cluster membership and notifying
instances of the changes. To ensure that GMS can detect changes in
cluster membership, a cluster's GMS settings must be configured
correctly.

The following topics are addressed here:

* link:#gjfqp[About GlassFish Server Clusters]
* link:#gjfnl[Group Management Service]
* link:#gkqdy[Creating, Listing, and Deleting Clusters]

[[gjfqp]][[GSHAG00183]][[about-glassfish-server-clusters]]

About GlassFish Server Clusters
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

A cluster is a named collection of GlassFish Server instances that share
the same applications, resources, and configuration information. For
information about GlassFish Server instances, see
link:instances.html#gkrbv[Administering GlassFish Server Instances].

GlassFish Server enables you to administer all the instances in a
cluster as a single unit from a single host, regardless of whether the
instances reside on the same host or different hosts. You can perform
the same operations on a cluster that you can perform on an unclustered
instance, for example, deploying applications and creating resources.

A cluster provides high availability through failure protection,
scalability, and load balancing.

* Failure protection. If an instance or a host in a cluster fails,
GlassFish Server detects the failure and recovers the user session
state. If a load balancer is configured for the cluster, the load
balancer redirects requests from the failed instance to other instances
in the cluster. Because the same applications and resources are on all
instances in the cluster, an instance can fail over to any other
instance in the cluster. +
To enable the user session state to be recovered, each instance in a
cluster sends in-memory state data to another instance. As state data is
updated in any instance, the data is replicated.
* Scalability. If increased capacity is required, you can add instances
to a cluster with no disruption in service. When an instance is added or
removed, the changes are handled automatically.
* Load balancing. If instances in a cluster are distributed among
different hosts, the workload can be distributed among the hosts to
increase overall system throughput.

[[gjfnl]][[GSHAG00184]][[group-management-service]]

Group Management Service
~~~~~~~~~~~~~~~~~~~~~~~~

The Group Management Service (GMS) is an infrastructure component that
is enabled for the instances in a cluster. When GMS is enabled, if a
clustered instance fails, the cluster and the Domain Administration
Server (DAS) are aware of the failure and can take action when failure
occurs. Many features of GlassFish Server depend upon GMS. For example,
GMS is used by the in-memory session replication, transaction service,
and timer service features.

GMS is a core service of the Shoal framework. For more information about
Shoal, visit the http://shoal.dev.java.net/[Project Shoal home page]
(`https://shoal.dev.java.net/`).

The following topics are addressed here:

* link:#CHDFEGAG[Protocols and Transports for GMS]
* link:#gjfpd[GMS Configuration Settings]
* link:#gjfog[Dotted Names for GMS Settings]
* link:#gkoac[To Preconfigure Nondefault GMS Configuration Settings]
* link:#gkqqo[To Change GMS Settings After Cluster Creation]
* link:#gklhl[To Check the Health of Instances in a Cluster]
* link:#gklhd[To Validate That Multicast Transport Is Available for a
Cluster]
* link:#CHDGAIBJ[Discovering a Cluster When Multicast Transport Is
Unavailable]
* link:#gjdlw[Using the Multi-Homing Feature With GMS]

[[CHDFEGAG]][[GSHAG485]][[protocols-and-transports-for-gms]]

Protocols and Transports for GMS
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

You can specify that GMS should use one of the following combinations of
protocol and transport for broadcasting messages:

* User Datagram Protocol (UDP) multicast
* Transmission Control Protocol (TCP) without multicast

Even if GMS should use UDP multicast for broadcasting messages, you must
ensure that TCP is enabled. On Windows systems, enabling TCP involves
enabling a protocol and port for security when a firewall is enabled.

If GMS should use UDP multicast for broadcasting messages and if
GlassFish Server instances in a cluster are located on different hosts,
the following conditions must be met:

* The DAS host and all hosts for the instances must be on the same
subnet.
* UDP multicast must be enabled for the network. To test whether
multicast is enabled, use the link:../reference-manual/validate-multicast.html#GSRFM00259[`validate-multicast`(1)]
subcommand.

If GMS should use TCP without multicast, you must configure GMS to
locate the instances to use for discovering the cluster. For more
information, see link:#CHDGAIBJ[Discovering a Cluster When Multicast
Transport Is Unavailable].


[width="100%",cols="<100%",]
|=======================================================================
a|
Note:

If you do not configure GMS to locate the instances to use for
discovering a cluster, GMS uses UDP multicast by default.

|=======================================================================


[[gjfpd]][[GSHAG00264]][[gms-configuration-settings]]

GMS Configuration Settings
^^^^^^^^^^^^^^^^^^^^^^^^^^

GlassFish Server has the following types of GMS settings:

* GMS cluster settings — These are determined during cluster creation.
For more information about these settings, see link:#gkqdm[To Create a
Cluster].
* GMS configuration settings — These are determined during configuration
creation and are explained here.

The following GMS configuration settings are used in GMS for group
discovery and failure detection:

`group-discovery-timeout-in-millis`::
  Indicates the amount of time (in milliseconds) an instance's GMS
  module will wait during instance startup for discovering other members
  of the group. +
  The `group-discovery-timeout-in-millis` timeout value should be set to
  the default or higher. The default is 5000.
`max-missed-heartbeats`::
  Indicates the maximum number of missed heartbeats that the health
  monitor counts before the instance can be marked as a suspected
  failure. GMS also tries to make a peer-to-peer connection with the
  suspected member. If the maximum number of missed heartbeats is
  exceeded and peer-to-peer connection fails, the member is marked as a
  suspected failure. The default is 3.
`heartbeat-frequency-in-millis`::
  Indicates the frequency (in milliseconds) at which a heartbeat is sent
  by each server instance to the cluster. +
  The failure detection interval is the `max-missed-heartbeats`
  multiplied by the `heartbeat-frequency-in-millis`. Therefore, the
  combination of defaults, 3 multiplied by 2000 milliseconds, results in
  a failure detection interval of 6 seconds. +
  Lowering the value of `heartbeat-frequency-in-millis` below the
  default would result in more frequent heartbeat messages being sent
  out from each member. This could potentially result in more heartbeat
  messages in the network than a system needs for triggering failure
  detection protocols. The effect of this varies depending on how
  quickly the deployment environment needs to have failure detection
  performed. That is, the (lower) number of retries with a lower
  heartbeat interval would make it quicker to detect failures. +
  However, lowering this value could result in false positives because
  you could potentially detect a member as failed when, in fact, the
  member's heartbeat is reflecting the network load from other parts of
  the server. Conversely, a higher timeout interval results in fewer
  heartbeats in the system because the time interval between heartbeats
  is longer. As a result, failure detection would take a longer. In
  addition, a startup by a failed member during this time results in a
  new join notification but no failure notification, because failure
  detection and verification were not completed. +
  The default is 2000.
`verify-failure-waittime-in-millis`::
  Indicates the verify suspect protocol's timeout used by the health
  monitor. After a member is marked as suspect based on missed
  heartbeats and a failed peer-to-peer connection check, the verify
  suspect protocol is activated and waits for the specified timeout to
  check for any further health state messages received in that time, and
  to see if a peer-to-peer connection can be made with the suspect
  member. If not, then the member is marked as failed and a failure
  notification is sent. The default is 1500.
`verify-failure-connect-timeout-in-millis`::
  Indicates the time it takes for the GMS to detect a hardware or
  network failure of a server instance. Be careful not to set this value
  too low. The smaller this timeout value is, the greater the chance of
  detecting false failures. That is, the instance has not failed but
  doesn't respond within the short window of time. The default is 10000.

The heartbeat frequency, maximum missed heartbeats, peer-to-peer
connection-based failure detection, and the verify timeouts are all
needed to ensure that failure detection is robust and reliable in
GlassFish Server.

For the dotted names for each of these GMS configuration settings, see
link:#gjfog[Dotted Names for GMS Settings]. For the steps to specify
these settings, see link:#gkoac[To Preconfigure Nondefault GMS
Configuration Settings].

[[gjfog]][[GSHAG00265]][[dotted-names-for-gms-settings]]

Dotted Names for GMS Settings
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Below are sample link:../reference-manual/get.html#GSRFM00139[`get`] subcommands to get all the GMS
configuration settings (attributes associated with the referenced
`mycfg` configuration) and GMS cluster settings (attributes and
properties associated with a cluster named `mycluster`).

[source,oac_no_warn]
----
asadmin> get "configs.config.mycfg.group-management-service.*"
configs.config.mycfg.group-management-service.failure-detection.heartbeat-frequency-in-millis=2000
configs.config.mycfg.group-management-service.failure-detection.max-missed-heartbeats=3
configs.config.mycfg.group-management-service.failure-detection.verify-failure-connect-timeout-in-millis=10000
configs.config.mycfg.group-management-service.failure-detection.verify-failure-waittime-in-millis=1500
configs.config.mycfg.group-management-service.group-discovery-timeout-in-millis=5000

asadmin> get clusters.cluster.mycluster
clusters.cluster.mycluster.config-ref=mycfg
clusters.cluster.mycluster.gms-bind-interface-address=${GMS-BIND-INTERFACE-ADDRESS-mycluster}
clusters.cluster.mycluster.gms-enabled=true
clusters.cluster.mycluster.gms-multicast-address=228.9.245.47
clusters.cluster.mycluster.gms-multicast-port=9833
clusters.cluster.mycluster.name=mycluster

asadmin> get "clusters.cluster.mycluster.property.*"
clusters.cluster.mycluster.property.GMS_LISTENER_PORT=${GMS_LISTENER_PORT-mycluster}
clusters.cluster.mycluster.property.GMS_MULTICAST_TIME_TO_LIVE=4
clusters.cluster.mycluster.property.GMS_LOOPBACK=false
clusters.cluster.mycluster.property.GMS_TCPSTARTPORT=9090
clusters.cluster.mycluster.property.GMS_TCPENDPORT=9200
----

The last `get` subcommand displays only the properties that have been
explicitly set.

For the steps to specify these settings, see link:#gkoac[To Preconfigure
Nondefault GMS Configuration Settings] and link:#gkqqo[To Change GMS
Settings After Cluster Creation].

[[gkoac]][[GSHAG00098]][[to-preconfigure-nondefault-gms-configuration-settings]]

To Preconfigure Nondefault GMS Configuration Settings
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

You can preconfigure GMS with values different than the defaults without
requiring a restart of the DAS and the cluster.

1.  Create a configuration using the link:../reference-manual/copy-config.html#GSRFM00011[`copy-config`]
subcommand. +
For example: +
[source,oac_no_warn]
----
asadmin> copy-config default-config mycfg
----
For more information, see link:named-configurations.html#abdjr[To Create
a Named Configuration].
2.  Set the values for the new configuration's GMS configuration
settings. +
For example: +
[source,oac_no_warn]
----
asadmin> set configs.config.mycfg.group-management-service.group-discovery-timeout-in-millis=8000
asadmin> set configs.config.mycfg.group-management-service.failure-detection.max-missed-heartbeats=5
----
For a complete list of the dotted names for these settings, see
link:#gjfog[Dotted Names for GMS Settings].
3.  Create the cluster so it uses the previously created configuration. +
For example: +
[source,oac_no_warn]
----
asadmin> create-cluster --config mycfg mycluster
----
You can also set GMS cluster settings during this step. For more
information, see link:#gkqdm[To Create a Cluster].
4.  Create server instances for the cluster. +
For example: +
[source,oac_no_warn]
----
asadmin> create-instance --node localhost --cluster mycluster instance01

asadmin> create-instance --node localhost --cluster mycluster instance02
----
5.  Start the cluster. +
For example: +
[source,oac_no_warn]
----
asadmin> start-cluster mycluster
----

[[GSHAG367]]

See Also

You can also view the full syntax and options of a subcommand by typing
`asadmin help` subcommand at the command line.

[[gkqqo]][[GSHAG00099]][[to-change-gms-settings-after-cluster-creation]]

To Change GMS Settings After Cluster Creation
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

To avoid the need to restart the DAS and the cluster, configure GMS
configuration settings before cluster creation as explained in
link:#gkoac[To Preconfigure Nondefault GMS Configuration Settings].

To avoid the need to restart the DAS and the cluster, configure the GMS
cluster settings during cluster creation as explained in link:#gkqdm[To
Create a Cluster].

Changing any GMS settings using the `set` subcommand after cluster
creation requires a domain administration server (DAS) and cluster
restart as explained here.

1.  Ensure that the DAS and cluster are running. +
Remote subcommands require a running server.
2.  Use the link:../reference-manual/get.html#GSRFM00139[`get`] subcommand to determine the settings
to change. +
For example: +
[source,oac_no_warn]
----
asadmin> get "configs.config.mycfg.group-management-service.*"
configs.config.mycfg.group-management-service.failure-detection.heartbeat-frequency-in-millis=2000
configs.config.mycfg.group-management-service.failure-detection.max-missed-heartbeats=3
configs.config.mycfg.group-management-service.failure-detection.verify-failure-connect-timeout-in-millis=10000
configs.config.mycfg.group-management-service.failure-detection.verify-failure-waittime-in-millis=1500
configs.config.mycfg.group-management-service.group-discovery-timeout-in-millis=5000
----
For a complete list of the dotted names for these settings, see
link:#gjfog[Dotted Names for GMS Settings].
3.  Use the link:../reference-manual/set.html#GSRFM00226[`set`] subcommand to change the settings. +
For example: +
[source,oac_no_warn]
----
asadmin> set configs.config.mycfg.group-management-service.group-discovery-timeout-in-millis=6000
----
4.  Use the `get` subcommand again to confirm that the changes were
made. +
For example: +
[source,oac_no_warn]
----
asadmin> get configs.config.mycfg.group-management-service.group-discovery-timeout-in-millis
----
5.  Restart the DAS. +
For example: +
[source,oac_no_warn]
----
asadmin> stop-domain domain1

asadmin> start-domain domain1
----
6.  Restart the cluster. +
For example: +
[source,oac_no_warn]
----
asadmin> stop-cluster mycluster

asadmin> start-cluster mycluster
----

[[GSHAG368]]

See Also

You can also view the full syntax and options of a subcommand by typing
`asadmin help` subcommand at the command line.

[[gklhl]][[GSHAG00100]][[to-check-the-health-of-instances-in-a-cluster]]

To Check the Health of Instances in a Cluster
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The `get-health` subcommand only works when GMS is enabled. This is the
quickest way to evaluate the health of a cluster and to detect if
cluster is properly operating; that is, all members of the cluster are
running and visible to DAS.

If multicast is not enabled for the network, all instances could be
running (as shown by the link:../reference-manual/list-instances.html#GSRFM00170[`list-instances`] subcommand),
yet isolated from each other. The `get-health` subcommand does not show
the instances if they are running but cannot discover each other due to
multicast not being configured properly. See link:#gklhd[To Validate
That Multicast Transport Is Available for a Cluster].

1.  Ensure that the DAS and cluster are running. +
Remote subcommands require a running server.
2.  Check whether server instances in a cluster are running by using the
link:../reference-manual/get-health.html#GSRFM00141[`get-health`] subcommand.

[[GSHAG00032]][[gklgw]]


Example 4-1 Checking the Health of Instances in a Cluster

This example checks the health of a cluster named `cluster1`.

[source,oac_no_warn]
----
asadmin> get-health cluster1
instance1 started since Wed Sep 29 16:32:46 EDT 2010
instance2 started since Wed Sep 29 16:32:45 EDT 2010
Command get-health executed successfully.
----

[[GSHAG369]]

See Also

You can also view the full syntax and options of the subcommand by
typing `asadmin help get-health` at the command line.

[[gklhd]][[GSHAG00101]][[to-validate-that-multicast-transport-is-available-for-a-cluster]]

To Validate That Multicast Transport Is Available for a Cluster
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[[GSHAG370]]

Before You Begin

To test a specific multicast address, multicast port, or bind interface
address, get this information beforehand using the `get` subcommand. Use
the following subcommand to get the multicast address and port for a
cluster named `c1`:

[source,oac_no_warn]
----
asadmin> get clusters.cluster.c1
clusters.cluster.c1.config-ref=mycfg
clusters.cluster.c1.gms-bind-interface-address=${GMS-BIND-INTERFACE-ADDRESS-c1}
clusters.cluster.c1.gms-enabled=true
clusters.cluster.c1.gms-multicast-address=228.9.174.162
clusters.cluster.c1.gms-multicast-port=5383
clusters.cluster.c1.name=c1
----

Use the following subcommand to get the bind interface address of a
server instance named `i1`that belongs to a cluster named `c1`, if this
system property has been set:

[source,oac_no_warn]
----
asadmin> get servers.server.i1.system-property.GMS-BIND-INTERFACE-ADDRESS-c1
servers.server.i1.system-property.GMS-BIND-INTERFACE-ADDRESS-c1.name=GMS-BIND-INTERFACE-ADDRESS-c1
servers.server.i1.system-property.GMS-BIND-INTERFACE-ADDRESS-c1.value=10.12.152.30
----

For information on how to set this system property, see
link:#gjdlw[Using the Multi-Homing Feature With GMS].


[width="100%",cols="<100%",]
|=======================================================================
a|
Note:

Do not run the `validate-multicast` subcommand using the DAS and
cluster's multicast address and port values while the DAS and cluster
are running. Doing so results in an error.

The `validate-multicast` subcommand must be run at the same time on two
or more machines to validate whether multicast messages are being
received between the machines.

|=======================================================================


Check whether multicast transport is available for a cluster by using
the link:../reference-manual/validate-multicast.html#GSRFM00259[`validate-multicast`] subcommand.

[[GSHAG00033]][[gklhv]]


Example 4-2 Validating That Multicast Transport Is Available for a
Cluster

This example checks whether multicast transport is available for a
cluster named `c1`.

Run from host `sr1`:

[source,oac_no_warn]
----
asadmin> validate-multicast
Will use port 2048
Will use address 228.9.3.1
Will use bind interface null
Will use wait period 2,000 (in milliseconds)

Listening for data...
Sending message with content "sr1" every 2,000 milliseconds
Received data from sr1 (loopback)
Received data from sr2
Exiting after 20 seconds. To change this timeout, use the --timeout command line option.
Command validate-multicast executed successfully.
----

Run from host `sr2`:

[source,oac_no_warn]
----
asadmin> validate-multicast
Will use port 2048
Will use address 228.9.3.1
Will use bind interface null
Will use wait period 2,000 (in milliseconds)

Listening for data...
Sending message with content "sr2" every 2,000 milliseconds
Received data from sr2 (loopback)
Received data from sr1
Exiting after 20 seconds. To change this timeout, use the --timeout command line option.
Command validate-multicast executed successfully.
----

[[GSHAG371]]

Next Steps

As long as all machines see each other, multicast is validated to be
working properly across the machines. If the machines are not seeing
each other, set the `--bindaddress` option explicitly to ensure that all
machines are using interface on same subnet, or increase the
`--timetolive` option from the default of `4`. If these changes fail to
resolve the multicast issues, ask the network administrator to verify
that the network is configured so the multicast messages can be seen
between all the machines used to run the cluster.

[[GSHAG372]]

See Also

You can also view the full syntax and options of the subcommand by
typing `asadmin help get-health` at the command line.

[[CHDGAIBJ]][[GSHAG00373]][[discovering-a-cluster-when-multicast-transport-is-unavailable]]

Discovering a Cluster When Multicast Transport Is Unavailable
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

When multicast transport is unavailable, GlassFish Server instances that
are joining a cluster cannot rely on broadcast messages from GMS to
discover the cluster. Instead, an instance that is joining a cluster
uses a running instance or the DAS in the cluster to discover the
cluster.

Therefore, when multicast transport is unavailable, you must provide the
locations of instances in the cluster to use for discovering the
cluster. You are not required to provide the locations of all instances
in the cluster. However, for an instance to discover the cluster, at
least one instance whose location you provide must be running. To
increase the probability of finding a running instance, provide the
locations of several instances.

If the DAS will be left running after the cluster is started, provide
the location of the DAS first in the list of instances. When a cluster
is started, the DAS is running before any of the instances in the
cluster are started.

The locations of the instances to use for discovering a cluster are part
of the configuration data that you provide when creating the cluster.
How to provide this data depends on how instances are distributed, as
explained in the following subsections:

* link:#CHDCGIFF[To Discover a Cluster When Multiple Instances in a
Cluster are Running on a Host]
* link:#CHDIGFCG[To Discover a Cluster When Each Instance in a Cluster
Is Running on a Different Host]

[[CHDCGIFF]][[GSHAG486]][[to-discover-a-cluster-when-multiple-instances-in-a-cluster-are-running-on-a-host]]

To Discover a Cluster When Multiple Instances in a Cluster are Running on a Host
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

If multiple instances in the same cluster are running on a host, you
must provide a list of uniform resource indicators (URIs). Each URI must
locate a GlassFish Server instance or the DAS in the cluster.

1.  Ensure that the DAS is running. +
Remote subcommands require a running server.
2.  Create a system property to represent the port number of the port on
which the DAS listens for messages from GMS for the cluster. +
Use the link:../reference-manual/create-system-properties.html#GSRFM00059[`create-system-properties`] subcommand for this
purpose. +
[source,oac_no_warn]
----
asadmin> create-system-properties GMS_LISTENER_PORT-cluster-name=gms-port
----
cluster-name::
  The name of the cluster to which the messages from GMS apply.
gms-port::
  The port number of the port on which the DAS listens for messages from
  GMS.
3.  Restart the DAS.
4.  When creating the cluster, set the `GMS_DISCOVERY_URI_LIST` property
to a comma-separated list of URIs that locate instances to use for
discovering the cluster. +
[source,oac_no_warn]
----
asadmin> create-cluster --properties GMS_DISCOVERY_URI_LIST=uri-list cluster-name
----
uri-list::
  A comma-separated list of URIs that locate a GlassFish Server instance
  or the DAS in the cluster. +
  The format of each URI in the list is as follows: +
  scheme`://`host-name-or -IP-address`:`port +
  * scheme is the URI scheme, which is `tcp`.
  * host-name-or -IP-address is the host name or IP address of the host
  on which the instance is running.
  * port is the port number of the port on which the instance will
  listen for messages from GMS.
cluster-name::
  The name of the cluster that you are creating. +

[width="100%",cols="<100%",]
|=======================================================================
a|
Note:

For complete instructions for creating a cluster, see link:#gkqdm[To
Create a Cluster].

|=======================================================================

5.  When you add each instance to the cluster, set the system property
`GMS_LISTENER_PORT-`clustername for the instance.
* To create the instance centrally, run the following command: +
[source,oac_no_warn]
----
asadmin> create-instance --node node-name
--systemproperties GMS_LISTENER_PORT-cluster-name=gms-port --cluster  cluster-name instance-name
----
* To create the instance locally, run the following command: +
[source,oac_no_warn]
----
asadmin> create-local-instance
--systemproperties GMS_LISTENER_PORT-cluster-name=gms-port --cluster  cluster-name instance-name
----
node-name::
  The name of an existing GlassFish Server node on which the instance is
  to reside. For more information about nodes, see
  link:nodes.html#gkrle[Administering GlassFish Server Nodes].
cluster-name::
  The name of the cluster to which the you are adding the instance.
gms-port::
  The port number of the port on which the instance listens for messages
  from GMS.
instance-name::
  The name of the instance that you are creating. +

[width="100%",cols="<100%",]
|=======================================================================
a|
Note:

For full instructions for adding an instance to a cluster, see the
following sections:

* link:instances.html#gkqch[To Create an Instance Centrally]
* link:instances.html#gkqbl[To Create an Instance Locally]

|=======================================================================


[[GSHAG487]][[sthref19]]


Example 4-3 Discovering a Cluster When Multiple Instances are Running on
a Host

This example creates a cluster that is named `tcpcluster` for which GMS
is not using multicast for broadcasting messages.

The cluster contains the instances `instance101` and `instance102`.
These instances reside on the host whose IP address is `10.152.23.224`
and listen for GMS events on ports 9091 and 9092. The DAS is also
running on this host and listens for GMS events on port 9090.

Instances that are joining the cluster will use the DAS and the
instances `instance101` and `instance102` to discover the cluster.

[source,oac_no_warn]
----
asadmin> create-system-properties GMS_LISTENER_PORT-tcpcluster=9090
Command create-system-properties executed successfully.
asadmin> restart-domain
Successfully restarted the domain
Command restart-domain executed successfully.
asadmin> create-cluster --properties GMS_DISCOVERY_URI_LIST=
tcp'\\:'//10.152.23.224'\\:'9090,
tcp'\\:'//10.152.23.224'\\:'9091,
tcp'\\:'//10.152.23.224'\\:'9092 tcpcluster
Command create-cluster executed successfully.
asadmin> create-local-instance
--systemproperties GMS_LISTENER_PORT-tcpcluster=9091 --cluster tcpcluster
instance101
Rendezvoused with DAS on localhost:4848.
Port Assignments for server instance instance101:
JMX_SYSTEM_CONNECTOR_PORT=28686
JMS_PROVIDER_PORT=27676
HTTP_LISTENER_PORT=28080
ASADMIN_LISTENER_PORT=24848
JAVA_DEBUGGER_PORT=29009
IIOP_SSL_LISTENER_PORT=23820
IIOP_LISTENER_PORT=23700
OSGI_SHELL_TELNET_PORT=26666
HTTP_SSL_LISTENER_PORT=28181
IIOP_SSL_MUTUALAUTH_PORT=23920
Command create-local-instance executed successfully.
asadmin> create-local-instance
--systemproperties GMS_LISTENER_PORT-tcpcluster=9092 --cluster tcpcluster
instance102
Rendezvoused with DAS on localhost:4848.
Using DAS host localhost and port 4848 from existing das.properties for node
localhost-domain1. To use a different DAS, create a new node using
create-node-ssh or create-node-config. Create the instance with the new node and
correct host and port:
asadmin --host das_host --port das_port create-local-instance --node node_name
instance_name.
Port Assignments for server instance instance102:
JMX_SYSTEM_CONNECTOR_PORT=28687
JMS_PROVIDER_PORT=27677
HTTP_LISTENER_PORT=28081
ASADMIN_LISTENER_PORT=24849
JAVA_DEBUGGER_PORT=29010
IIOP_SSL_LISTENER_PORT=23821
IIOP_LISTENER_PORT=23701
OSGI_SHELL_TELNET_PORT=26667
HTTP_SSL_LISTENER_PORT=28182
IIOP_SSL_MUTUALAUTH_PORT=23921
Command create-local-instance executed successfully.
----

[[GSHAG488]]

See Also

* link:../reference-manual/create-system-properties.html#GSRFM00059[`create-system-properties`(1)]
* link:#gkqdm[To Create a Cluster]
* link:instances.html#gkqch[To Create an Instance Centrally]
* link:instances.html#gkqbl[To Create an Instance Locally]

[[CHDIGFCG]][[GSHAG489]][[to-discover-a-cluster-when-each-instance-in-a-cluster-is-running-on-a-different-host]]

To Discover a Cluster When Each Instance in a Cluster Is Running on a Different Host
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

If all instances in a cluster and the DAS are running on different
hosts, you can specify the locations of instances to use for discovering
the cluster as follows:

* By specifying a list of host names or Internet Protocol (IP)
addresses. Each host name or IP address must locate a host on which the
DAS or a GlassFish Server instance in the cluster is running. Instances
that are joining the cluster will use the DAS or the instances to
discover the cluster.
* By generating the list of locations automatically. The generated list
contains the locations of the DAS and all instances in the cluster.

Multiple instances on the same host cannot be members of the same
cluster.

1.  Ensure that the DAS is running. +
Remote subcommands require a running server.
2.  When creating the cluster, set the properties of the cluster as
follows:
* Set the `GMS_DISCOVERY_URI_LIST` property to one of the following
values:

** A comma-separated list of IP addresses or host names on which the DAS
or the instances to use for discovering the cluster are running. +
The list can contain a mixture of IP addresses and host names.

** The keyword `generate`.
* Set the `GMS_LISTENER_PORT` property to a port number that is unique
for the cluster in the domain. +
If you are specifying a list of IP addresses or host names, type the
following command: +
[source,oac_no_warn]
----
asadmin> create-cluster --properties GMS_DISCOVERY_URI_LIST=host-list:
GMS_LISTENER_PORT=gms-port cluster-name
----
If you are specifying the keyword `generate`, type the following
command: +
[source,oac_no_warn]
----
asadmin> create-cluster --properties GMS_DISCOVERY_URI_LIST=generate:
GMS_LISTENER_PORT=gms-port cluster-name
----
host-list::
  A comma-separated list of IP addresses or host names on which the DAS
  or the instances to use for discovering the cluster are running.
gms-port::
  The port number of the port on which the cluster listens for messages
  from GMS.
cluster-name::
  The name of the cluster that you are creating. +

[width="100%",cols="<100%",]
|=======================================================================
a|
Note:

For complete instructions for creating a cluster, see link:#gkqdm[To
Create a Cluster].

|=======================================================================


[[GSHAG490]][[sthref20]]


Example 4-4 Discovering a Cluster by Specifying a List of IP Addresses

This example creates a cluster that is named `ipcluster` for which GMS
is not using multicast for broadcasting messages. The instances to use
for discovering the cluster are located through a list of IP addresses.
In this example, one instance in the cluster is running on each host and
the DAS is running on a separate host. The cluster listens for messages
from GMS on port 9090.

[source,oac_no_warn]
----
asadmin> create-cluster --properties 'GMS_DISCOVERY_URI_LIST=
10.152.23.225,10.152.23.226,10.152.23.227,10.152.23.228:
GMS_LISTENER_PORT=9090' ipcluster
Command create-cluster executed successfully.
----

[[GSHAG491]][[sthref21]]


Example 4-5 Discovering a Cluster by Generating a List of Locations of
Instances

This example creates a cluster that is named `gencluster` for which GMS
is not using multicast for broadcasting messages. The list of locations
of instances to use for discovering the cluster is generated
automatically. In this example, one instance in the cluster is running
on each host and the DAS is running on a separate host. The cluster
listens for messages from GMS on port 9090.

[source,oac_no_warn]
----
asadmin> create-cluster --properties 'GMS_DISCOVERY_URI_LIST=generate:
GMS_LISTENER_PORT=9090' gencluster
Command create-cluster executed successfully.
----

[[GSHAG492]]

Next Steps

After creating the cluster, add instances to the cluster as explained in
the following sections:

* link:instances.html#gkqch[To Create an Instance Centrally]
* link:instances.html#gkqbl[To Create an Instance Locally]

[[GSHAG493]]

See Also

* link:#gkqdm[To Create a Cluster]
* link:instances.html#gkqch[To Create an Instance Centrally]
* link:instances.html#gkqbl[To Create an Instance Locally]

[[gjdlw]][[GSHAG00266]][[using-the-multi-homing-feature-with-gms]]

Using the Multi-Homing Feature With GMS
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Multi-homing enables GlassFish Server clusters to be used in an
environment that uses multiple Network Interface Cards (NICs). A
multi-homed host has multiple network connections, of which the
connections may or may not be the on same network. Multi-homing provides
the following benefits:

* Provides redundant network connections within the same subnet. Having
multiple NICs ensures that one or more network connections are available
for communication.
* Supports communication across two or more different subnets. The DAS
and all server instances in the same cluster must be on the same subnet
for GMS communication, however.
* Binds to a specific IPv4 address and receives GMS messages in a system
that has multiple IP addresses configured. The responses for GMS
messages received on a particular interface will also go out through
that interface.
* Supports separation of external and internal traffic.

[[gjdoo]][[GSHAG00224]][[traffic-separation-using-multi-homing]]

Traffic Separation Using Multi-Homing
+++++++++++++++++++++++++++++++++++++

You can separate the internal traffic resulting from GMS from the
external traffic. Traffic separation enables you plan a network better
and augment certain parts of the network, as required.

Consider a simple cluster, `c1`, with three instances, `i101`, `i102`,
and `i103`. Each instance runs on a different machine. In order to
separate the traffic, the multi-homed machine should have at least two
IP addresses belonging to different networks. The first IP as the
external IP and the second one as internal IP. The objective is to
expose the external IP to user requests, so that all the traffic from
the user requests would be through them. The internal IP is used only by
the cluster instances for internal communication through GMS. The
following procedure describes how to set up traffic separation.

To configure multi-homed machines for GMS without traffic separation,
skip the steps or commands that configure the `EXTERNAL-ADDR` system
property, but perform the others.

To avoid having to restart the DAS or cluster, perform the following
steps in the specified order.

To set up traffic separation, follow these steps:

1.  Create the system properties `EXTERNAL-ADDR` and
`GMS-BIND-INTERFACE-ADDRESS-c1` for the DAS.
* `asadmin create-system-properties` `target`
`server EXTERNAL-ADDR=192.155.35.4`
* `asadmin create-system-properties` `target`
`server GMS-BIND-INTERFACE-ADDRESS-c1=10.12.152.20`
2.  Create the cluster with the default settings. +
Use the following command: +
[source,oac_no_warn]
----
asadmin create-cluster c1
----
A reference to a system property for GMS traffic is already set up by
default in the `gms-bind-interface-address` cluster setting. The default
value of this setting is `${GMS-BIND-INTERFACE-ADDRESS-`cluster-name`}`.
3.  When creating the clustered instances, configure the external and
GMS IP addresses. +
Use the following commands:
* `asadmin create-instance` `node` `localhost` `cluster` `c1`
`systemproperties`
`EXTERNAL-ADDR=192.155.35.5:GMS-BIND-INTERFACE-ADDRESS-c1=10.12.152.30 i101`
* `asadmin create-instance` `node` `localhost` `cluster` `c1`
`systemproperties`
`EXTERNAL-ADDR=192.155.35.6:GMS-BIND-INTERFACE-ADDRESS-c1=10.12.152.40 i102`
* `asadmin create-instance` `node` `localhost` `cluster` `c1`
`systemproperties`
`EXTERNAL-ADDR=192.155.35.7:GMS-BIND-INTERFACE-ADDRESS-c1=10.12.152.50 i103`
4.  Set the address attribute of HTTP listeners to refer to the
`EXTERNAL-ADDR` system properties. +
Use the following commands: +
[source,oac_no_warn]
----
asadmin set c1-config.network-config.network-listeners.network-listener.http-1.address=\${EXTERNAL-ADDR}
asadmin set c1-config.network-config.network-listeners.network-listener.http-2.address=\${EXTERNAL-ADDR}
----

[[gkqdy]][[GSHAG00185]][[creating-listing-and-deleting-clusters]]

Creating, Listing, and Deleting Clusters
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

GlassFish Server enables you to create clusters, obtain information
about clusters, and delete clusters that are no longer required.

The following topics are addressed here:

* link:#gkqdm[To Create a Cluster]
* link:#gkqdn[To List All Clusters in a Domain]
* link:#gkqcp[To Delete a Cluster]

[[gkqdm]][[GSHAG00103]][[to-create-a-cluster]]

To Create a Cluster
^^^^^^^^^^^^^^^^^^^

Use the `create-cluster` subcommand in remote mode to create a cluster.

To ensure that the GMS can detect changes in cluster membership, a
cluster's GMS settings must be configured correctly. To avoid the need
to restart the DAS and the cluster, configure a cluster's GMS settings
when you create the cluster. If you change GMS settings for an existing
cluster, the DAS and the cluster must be restarted to apply the changes.

When you create a cluster, GlassFish Server automatically creates a
Message Queue cluster for the GlassFish Server cluster. For more
information about Message Queue clusters, see link:jms.html#abdbx[Using
Message Queue Broker Clusters With GlassFish Server].

[[GSHAG374]]

Before You Begin

If the cluster is to reference an existing named configuration, ensure
that the configuration exists. For more information, see
link:named-configurations.html#abdjr[To Create a Named Configuration]. If
you are using a named configuration to preconfigure GMS settings, ensure
that these settings have the required values in the named configuration.
For more information, see link:#gkoac[To Preconfigure Nondefault GMS
Configuration Settings].

If you are configuring the cluster's GMS settings when you create the
cluster, ensure that you have the following information:

* The address on which GMS listens for group events
* The port number of the communication port on which GMS listens for
group events
* The maximum number of iterations or transmissions that a multicast
message for GMS events can experience before the message is discarded
* The lowest port number in the range of ports from which GMS selects a
TCP port on which to listen
* The highest port number in the range of ports from which GMS selects a
TCP port on which to listen

If the DAS is running on a multihome host, ensure that you have the
Internet Protocol (IP) address of the network interface on the DAS host
to which GMS binds.

1.  Ensure that the DAS is running. +
Remote subcommands require a running server.
2.  [[gkrco]]
Run the `create-cluster` subcommand.


[width="100%",cols="<100%",]
|=======================================================================
a|
Note:

Only the options that are required to complete this task are provided in
this step. For information about all the options for configuring the
cluster, see the link:../reference-manual/create-cluster.html#GSRFM00017[`create-cluster`(1)] help page.

|=======================================================================


* If multicast transport is available, run the `create-cluster`
subcommand as follows: +
[source,oac_no_warn]
----
asadmin> create-cluster --config configuration
--multicastaddress multicast-address --multicastport multicast-port
--properties GMS_MULTICAST_TIME_TO_LIVE=max-iterations:
GMS_TCPSTARTPORT=start-port:GMS_TCPENDPORT=end-port cluster-name
----
* If multicast transport is not available, run the `create-cluster`
subcommand as follows: +
[source,oac_no_warn]
----
asadmin> create-cluster --config configuration
--properties GMS_DISCOVERY_URI_LIST=discovery-instances:
GMS_LISTENER_PORT=gms-port
cluster-name
----

configuration::
  An existing named configuration that the cluster is to reference.
multicast-address::
  The address on which GMS listens for group events.
multicast-port::
  The port number of the communication port on which GMS listens for
  group events.
max-iterations::
  The maximum number of iterations or transmissions that a multicast
  message for GMS events can experience before the message is discarded.
discovery-instances::
  Instances to use for discovering the cluster. For more information,
  see link:#CHDGAIBJ[Discovering a Cluster When Multicast Transport Is
  Unavailable].
gms-port::
  The port number of the port on which the cluster listens for messages
  from GMS.
start-port::
  The lowest port number in the range of ports from which GMS selects a
  TCP port on which to listen. The default is 9090.
end-port::
  The highest port number in the range of ports from which GMS selects a
  TCP port on which to listen. The default is 9200.
cluster-name::
  Your choice of name for the cluster that you are creating.
3.  If necessary, create a system property to represent the IP address
of the network interface on the DAS host to which GMS binds. +
This step is necessary only if the DAS is running on a multihome host. +
[source,oac_no_warn]
----
asadmin> create-system-properties
GMS-BIND-INTERFACE-ADDRESS-cluster-name=das-bind-address
----
cluster-name::
  The name that you assigned to the cluster in Step link:#gkrco[2].
das-bind-address::
  The IP address of the network interface on the DAS host to which GMS
  binds.

[[GSHAG00034]][[gkqaz]]


Example 4-6 Creating a Cluster for a Network in Which Multicast
Transport Is Available

This example creates a cluster that is named `ltscluster` for which port
1169 is to be used for secure IIOP connections. Because the `--config`
option is not specified, the cluster references a copy of the named
configuration `default-config` that is named `ltscluster-config`. This
example assumes that multicast transport is available.

[source,oac_no_warn]
----
asadmin> create-cluster
--systemproperties IIOP_SSL_LISTENER_PORT=1169
ltscluster
Command create-cluster executed successfully.
----

[[GSHAG00035]][[gkqiq]]


Example 4-7 Creating a Cluster and Setting GMS Options for a Network in
Which Multicast Transport Is Available

This example creates a cluster that is named `pmdcluster`, which
references the existing configuration `clusterpresets` and for which the
cluster's GMS settings are configured as follows:

* GMS listens for group events on address 228.9.3.1 and port 2048.
* A multicast message for GMS events is discarded after 3 iterations or
transmissions.
* GMS selects a TCP port on which to listen from ports in the range
10000-10100.

This example assumes that multicast transport is available.

[source,oac_no_warn]
----
asadmin> create-cluster --config clusterpresets
--multicastaddress 228.9.3.1 --multicastport 2048
--properties GMS_MULTICAST_TIME_TO_LIVE=3:
GMS_TCPSTARTPORT=10000:GMS_TCPENDPORT=10100 pmdcluster
Command create-cluster executed successfully.
----

[[GSHAG375]]

Next Steps

After creating a cluster, you can add GlassFish Server instances to the
cluster as explained in the following sections:

* link:instances.html#gkqch[To Create an Instance Centrally]
* link:instances.html#gkqbl[To Create an Instance Locally]

[[GSHAG376]]

See Also

* link:named-configurations.html#abdjr[To Create a Named Configuration]
* link:#gkoac[To Preconfigure Nondefault GMS Configuration Settings]
* link:jms.html#abdbx[Using Message Queue Broker Clusters With GlassFish
Server]
* link:../reference-manual/create-cluster.html#GSRFM00017[`create-cluster`(1)]
* link:../reference-manual/create-system-properties.html#GSRFM00059[`create-system-properties`(1)]

You can also view the full syntax and options of the subcommands by
typing the following commands at the command line:

* `asadmin help create-cluster`
* `asadmin help create-system-properties`

[[gkqdn]][[GSHAG00104]][[to-list-all-clusters-in-a-domain]]

To List All Clusters in a Domain
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Use the `list-clusters` subcommand in remote mode to obtain information
about existing clusters in a domain.

1.  Ensure that the DAS is running. +
Remote subcommands require a running server.
2.  Run the link:../reference-manual/list-clusters.html#GSRFM00153[`list-clusters`] subcommand. +
[source,oac_no_warn]
----
asadmin> list-clusters
----

[[GSHAG00036]][[gksfc]]


Example 4-8 Listing All Clusters in a Domain

This example lists all clusters in the current domain.

[source,oac_no_warn]
----
asadmin> list-clusters
pmdclust not running
ymlclust not running
Command list-clusters executed successfully.
----

[[GSHAG00037]][[gkhsp]]


Example 4-9 Listing All Clusters That Are Associated With a Node

This example lists the clusters that contain an instance that resides on
the node `sj01`.

[source,oac_no_warn]
----
asadmin> list-clusters sj01
ymlclust not running
Command list-clusters executed successfully.
----

[[GSHAG377]]

See Also

link:../reference-manual/list-clusters.html#GSRFM00153[`list-clusters`(1)]

You can also view the full syntax and options of the subcommand by
typing `asadmin help list-clusters` at the command line.

[[gkqcp]][[GSHAG00105]][[to-delete-a-cluster]]

To Delete a Cluster
^^^^^^^^^^^^^^^^^^^

Use the `delete-cluster` subcommand in remote mode to remove a cluster
from the DAS configuration.

If the cluster's named configuration was created automatically for the
cluster and no other clusters or unclustered instances refer to the
configuration, the configuration is deleted when the cluster is deleted.

[[GSHAG378]]

Before You Begin

Ensure that following prerequisites are met:

* The cluster that you are deleting is stopped. For information about
how to stop a cluster, see link:instances.html#gkqcl[To Stop a Cluster].
* The cluster that you are deleting contains no GlassFish Server
instances. For information about how to remove instances from a cluster,
see the following sections:

** link:instances.html#gkqcw[To Delete an Instance Centrally]

** link:instances.html#gkqed[To Delete an Instance Locally]

1.  Ensure that the DAS is running. +
Remote subcommands require a running server.
2.  Confirm that the cluster is stopped. +
[source,oac_no_warn]
----
asadmin> list-clusters cluster-name
----
cluster-name::
  The name of the cluster that you are deleting.
3.  Confirm that the cluster contains no instances. +
[source,oac_no_warn]
----
asadmin> list-instances cluster-name
----
cluster-name::
  The name of the cluster that you are deleting.
4.  Run the link:../reference-manual/delete-cluster.html#GSRFM00068[`delete-cluster`] subcommand. +
[source,oac_no_warn]
----
asadmin> delete-cluster cluster-name
----
cluster-name::
  The name of the cluster that you are deleting.

[[GSHAG00038]][[gkqkr]]


Example 4-10 Deleting a Cluster

This example confirms that the cluster `adccluster` is stopped and
contains no instances and deletes the cluster `adccluster`.

[source,oac_no_warn]
----
asadmin> list-clusters adccluster
adccluster not running
Command list-clusters executed successfully.
asadmin> list-instances adccluster
Nothing to list.
Command list-instances executed successfully.
asadmin> delete-cluster adccluster
Command delete-cluster executed successfully.
----

[[GSHAG379]]

See Also

* link:instances.html#gkqcl[To Stop a Cluster]
* link:instances.html#gkqcw[To Delete an Instance Centrally]
* link:instances.html#gkqed[To Delete an Instance Locally]
* link:../reference-manual/delete-cluster.html#GSRFM00068[`delete-cluster`(1)]
* link:../reference-manual/list-clusters.html#GSRFM00153[`list-clusters`(1)]
* link:../reference-manual/list-instances.html#GSRFM00170[`list-instances`(1)]

You can also view the full syntax and options of the subcommands by
typing the following commands at the command line:

* `asadmin help delete-cluster`
* `asadmin help list-clusters`
* `asadmin help list-instances`