ClusterMBean

Overview

This bean represents a cluster in the domain. Servers join a cluster by calling ServerMBean.setCluster with the logical name of the cluster. A configuration may define zero or more clusters. They may be looked up by logical name. The name of a cluster denotes its logical cluster name.

Related MBeans

This section describes attributes that provide access to other MBeans. For more information about the MBean hierarchy, refer to WebLogic Server MBean Data Model.

CandidateMachinesForMigratableServers

The set of machines (and order of preference) on which Node Manager will restart failed servers. (Requires you to enable each server for automatic migration.)

Each server can specify a subset of these cluster-wide candidates, which limits the machines on which the server can be restarted. Servers can also specify their own order of preference.

For more information, see:

• ServerMBean#getCandidateMachinesForMigratableServers

DataSourceForAutomaticMigration

The data source used by servers in the cluster during migration. (You must configure each Migratable Server within the cluster to use this data source.)

DataSourceForSessionPersistence

To support HTTP Session failover across data centers, requires a datasource to dump session state on disk.

OverloadProtection

Get attributes related to server overload protection. The default values for all cluster members are set here. Individual servers can override them as needed.

Servers

The servers which have declared membership in this cluster.

Attributes

This section describes the following attributes:

AdditionalAutoMigrationAttempts

A migratable server could fail to come up on every possible configured machine. This attribute controls how many further attempts, after the first one, should be tried. Note that each attempt specified here indicates another full circut of migrations amongst all the configured machines. So for a 3-server cluster, and the default value of 3, a total of 9 migrations will be attempted. If it is set to -1, migrations will go on forever until the server starts.

AutoMigrationTableName

Return the name of the table to be used for server migration.

ClientCertProxyEnabled

Specifies whether to honor the WL-Proxy-Client-Cert header coming with the request or not.

For more information, see:

• WebAppContainerMBean#isClientCertProxyEnabled()
• ServerMBean#isClientCertProxyEnabled()

ClusterAddress

The address that forms a portion of the URL a client uses to connect to this cluster, and that is used for generating EJB handles and entity EJB failover addresses. (This address may be either a DNS host name that maps to multiple IP addresses or a comma-separated list of single address host names or IP addresses.)

Defines the address to be used by clients to connect to this cluster. This address may be either a DNS host name that maps to multiple IP addresses or a comma separated list of single address host names or IP addresses. If network channels are configured, it is possible to set the cluster address on a per channel basis.

For more information, see:

• NetworkChannelMBean#getClusterAddress

ClusterType

Optimizes cross-cluster replication for the type of network that servers in the clusters use for administrative communication.

To enhance the reliability of HTTP sessions, you can configure servers in one cluster to replicate the session data to servers in a different cluster. In such an environment, configure the clusters to be one of the following types:

• man

  if the clustered servers can send their data through a metro area network (man) in which latency is negligible. With this ClusterType value, servers replicate session state synchronously and in memory only. For example, when serverA in cluster1 starts an HTTP session, its backup server, serverB in cluster2, immediately replicates this session in memory to Server B.

• wan

  if the clusters are far apart or send their data through a wide area network (wan) that experiences significant network latency. With this ClusterType value, a server replicates session state synchronously to the backup server in the same cluster and asynchronously to a server in the remote cluster. For example, when serverA in cluster1 starts an HTTP session, it sends the data to serverB in cluster1 and then asynchronously sends data to serverX in cluster 2. ServerX will persist the session state in the database.

  If you persist session data in a replicating database, and if you prefer to use the database to replicate the data instead of WebLogic Server, choose a cluster type of wan and leave the remote cluster address undefined. WebLogic Server saves the session data to the local database and assumes that the database replicates data as needed.

DefaultLoadAlgorithm

The algorithm to be used for load-balancing between replicated services if none is specified for a particular service. The round-robin algorithm cycles through a list of WebLogic Server instances in order. Weight-based load balancing improves on the round-robin algorithm by taking into account a pre-assigned weight for each server. In random load balancing, requests are routed to servers at random.

Defines the algorithm to be used for load-balancing between replicated services if none is specified for a particular service.

FencingGracePeriodMillis

During automatic migration, if the Cluster Master determines a server to be dead, it waits for this period of time (in milliseconds) before the Cluster Master migrates the service to another server in the cluster.

FrontendHost

The name of the host to which all redirected URLs will be sent.

Sets the HTTP FrontendHost for the default webserver (not virtual hosts) for all the servers in the cluster. Provides a method to ensure that the webapp will always have the correct HOST information, even when the request is coming through a firewall or a proxy. If this parameter is configured, the HOST header will be ignored and the information in this parameter will be used in its place, when constructing the absolute urls for redirects.

For more information, see:

• WebServerMBean#getFrontendHost

FrontendHTTPPort

The name of the HTTP port to which all redirected URLs will be sent.

Sets the FrontendHTTPPort for the default webserver (not virtual hosts) for all the servers in the cluster. Provides a method to ensure that the webapp will always have the correct PORT information, even when the request is coming through a firewall or a proxy. If this parameter is configured, the HOST header will be ignored and the information in this parameter will be used in its place, when constructing the absolute urls for redirects.

For more information, see:

• WebServerMBean#getFrontendHTTPPort

FrontendHTTPSPort

The name of the secure HTTP port to which all redirected URLs will be sent.

Sets the FrontendHTTPSPort for the default webserver (not virtual hosts) for all the servers in the cluster. Provides a method to ensure that the webapp will always have the correct PORT information, even when the request is coming through a firewall or a proxy. If this parameter is configured, the HOST header will be ignored and the information in this parameter will be used in its place, when constructing the absolute urls for redirects.

For more information, see:

• WebServerMBean#getFrontendHTTPSPort

HealthCheckIntervalMillis

Interval in milliseconds at which Migratable Servers and Cluster Masters prove their liveness via the database.

HealthCheckPeriodsUntilFencing

Maximum number of periods that a cluster member will wait before timing out a Cluster Master and also the maximum number of periods the Cluster Master will wait before timing out a Migratable Server.

HttpTraceSupportEnabled

Returns the value of HttpTraceSupportEnabled.

For more information, see:

• WebAppContainerMBean#isHttpTraceSupportEnabled
• ServerMBean#isHttpTraceSupportEnabled

IdlePeriodsUntilTimeout

Maximum number of periods that a cluster member will wait before timing out a member of a cluster.

Maximum number of periods that a cluster member will wait before timing out a member of a cluster.

InterClusterCommLinkHealthCheckInterval

If the cluster link between two clusters goes down, a trigger will run to periodically to see if the link is restored. The duration is specified in milliseconds.

MemberWarmupTimeoutSeconds

Maximum number of seconds that a cluster member will wait to discover and synchronize with other servers in the cluster. Normally, the member will be able to sync in 30 seconds. If the value of this attribute is higher, that does not necessarily mean that it will take longer for the member to warmup. Instead it defines an upper bound on the time that a server will wait to sync with the servers that it has discoverred. If the value is set 0, servers will not attempt to discover other running server in the cluster during server initialization

MillisToSleepBetweenAutoMigrationAttempts

Controls how long of a pause there should be between the migration attempts described in getAdditionalAutoMigrationAttempts(). Note that this delay only happens when the server has failed to come up on every machine.

For more information, see:

• getAdditionalAutoMigrationAttempts

MulticastAddress

The multicast address used by cluster members to communicate with each other.

The valid range is from from 224.0.0.0 to 239.255.255.255. The default value used by WebLogic Server is 239.192.0.0. You should avoid using multicast addresses in the range x.0.0.1

This address should be unique to this cluster and should not be shared by other applications.

For more information, see:

• ServerMBean#getInterfaceAddress
• getMulticastPort

MulticastBufferSize

The multicast socket send/receive buffer size (at least 64 kilobytes).

Returns the multicast socket send/receive buffer size.

MulticastDataEncryption

Enables multicast data to be incrypted. Only the multicast data is encrypted. Multicast header information is not encrypted.

MulticastPort

The multicast port (between 1 and 65535) used by cluster members to communicate with each other.

Defines the multicast port used by cluster members to communicate with each other.

For more information, see:

• setMulticastPort
• getMulticastAddress

MulticastSendDelay

The amount of time (between 0 and 100 milliseconds) to delay sending message fragments over multicast in order to avoid OS-level buffer overflow.

Defines the number of milliseconds to delay sending message fragments over multicast in order to avoid OS-level buffer overflow.

MulticastTTL

The number of network hops (between 1 and 255) that a cluster multicast message is allowed to travel.

Defines the number of network hops that a cluster multicast message is allowed to travel. 1 restricts the cluster to one subnet.

Name

The user-specified name of this MBean instance.

This name is included as one of the key properties in the MBean's javax.management.ObjectName:
Name=user-specified-name

Notes

Optional information that you can include to describe this configuration.

WebLogic Sever saves this note in the domain's configuration file (config.xml) as XML PCDATA. All left angle brackets (<) are converted to the XML entity <. Carriage returns/line feeds are preserved.

Note:

If you create or edit a note from the Administration Console, the Administration Console does not preserve carriage returns/line feeds.

NumberOfServersInClusterAddress

Number of servers to be listed from this cluster when generating a cluster address automatically. This setting has no effect if Cluster Address is explicitly set.

For more information, see:

• getClusterAddress

Parent

Return the immediate parent for this MBean

RemoteClusterAddress

Set the foreign cluster. Cluster infrastructure uses this address to connect to foreign cluster for HTTP Session WAN/MAN failover.

ReplicationChannel

The channel name to be used for replication traffic. Cluster infrastructure uses this channel to send updates for HTTP sessions and stateful session beans. If none is set then the default channel will be used.

In order for this feature to work, the named channel must exist on all members of the cluster and must be configured to use the same protocol. It is valid for the selected channel to be configured to use a secure protocol.

For more information, see:

• getRemoteClusterAddress

ReplicationTimeoutEnabled

Indicates if timeout should be applied to session replication calls.

ServiceAgeThresholdSeconds

The number of seconds (between 0 and 65534) by which the age of two conflicting services must differ before one is considered older than the other.

Defines the number of seconds by which the age of two conflicting services must differ before one is considered older than the other.

SessionFlushInterval

Interval in seconds until HTTP Sessions are periodically flushed to the backup cluster to dump session state on disk.

SessionFlushThreshold

When number of sessions to be flushed reaches this threshold limit, sessions will be flushed to the backup cluster before the flush interval. This helps the server to flush sessions faster under load.

Type

Returns the type of the MBean.

WeblogicPluginEnabled

Specifies whether the proprietary WL-Proxy-Client-IP header should be used. (This needed only when WebLogic plugins are configured.)

Gets the weblogicPluginEnabled attribute of the ClusterMBean object

For more information, see:

• WebAppContainerMBean#isWeblogicPluginEnabled()
• ServerMBean#isWeblogicPluginEnabled()

Operations

This section describes the following operations:

freezeCurrentValue

If the specified attribute has not been set explicitly, and if the attribute has a default value, this operation forces the MBean to persist the default value.

Unless you use this operation, the default value is not saved and is subject to change if you update to a newer release of WebLogic Server. Invoking this operation isolates this MBean from the effects of such changes.

Note:

To insure that you are freezing the default value, invoke the restoreDefaultValue operation before you invoke this.

This operation has no effect if you invoke it on an attribute that does not provide a default value or on an attribute for which some other value has been set.

Deprecated. 9.0.0.0

isSet

Returns true if the specified attribute has been set explicitly in this MBean instance.

kill

Used to force a Shutdown of all the servers belonging to the Cluster.

restoreDefaultValue

If the specified attribute has a default value, this operation removes any value that has been set explicitly and causes the attribute to use the default value.

Default values are subject to change if you update to a newer release of WebLogic Server. To prevent the value from changing if you update to a newer release, invoke the freezeCurrentValue operation.

This operation has no effect if you invoke it on an attribute that does not provide a default value or on an attribute that is already using the default.

Deprecated. 9.0.0.0

start

Used to start all the servers belonging to the Cluster. HashMap contains references to TaskRuntimeMBeans corresponding to each server in the Cluster, keyed using the server name.

unSet

Restore the given property to its default value.