Column Display Related Tasks Related Topics
This page summarizes the clusters that have been configured in the current WebLogic Server domain.
A cluster defines groups of WebLogic Server servers that work together to increase scalability and reliability.
A cluster appears to clients to be a single WebLogic Server instance. The servers that constitute a cluster can run on the same machine, or be located on different machines.
You can show fewer or additional data points on this page by expanding Customize this table and modifying the Column Display list. Each data point displays in its own table column.
The following table lists all of the data points that you can display in columns on this page.
Name Description Name
The name that you specified when you created the cluster.
The servers which have declared membership in this cluster.
Cluster Messaging Mode
Specifies the messaging type used in the cluster.
Multicast messaging is provided for backwards compatibility.
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:
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.
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
wanand 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.
Controls the mechanism used for server and service migration.
-- Requires the availability of a high-availability database, such as Oracle RAC, to store leasing information.
-- Stores the leasing information in-memory within a cluster member. This option requires Node Manager to be configured and running.
Note: Within a WebLogic Server installation, you can only use one type of leasing. Although it is possible to implement multiple features that use leasing within your environment, each must use the same kind of leasing.
Default Load Algorithm
Defines the algorithm to be used for load-balancing between replicated services if none is specified for a particular service. The
round-robinalgorithm cycles through a list of WebLogic Server instances in order.
Weight-basedload balancing improves on the round-robin algorithm by taking into account a pre-assigned weight for each server. In
randomload balancing, requests are routed to servers at random.
Cluster Broadcast Channel
Specifies the channel used to handle communications within a cluster. If no channel is specified the default channel is used.
ClusterBroadcastChannel is only are supported if the unicast messaging type is used.
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.
The multicast address used by cluster members to communicate with each other.
The valid range is from from 184.108.40.206 to 220.127.116.11. The default value used by WebLogic Server is 18.104.22.168. 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.
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.
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.
Multicast Buffer Size
The multicast socket send/receive buffer size (at least 64 kilobytes).
Returns the multicast socket send/receive buffer size.
Multicast Send Delay
The amount of time (between 0 and 250 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.
Service Age Threshold Seconds
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.
Client Cert Proxy Enabled
Specifies whether to honor the WL-Proxy-Client-Cert header coming with the request or not.
Weblogic Plugin Enabled
Specifies if this cluster will receive requests from a proxy plug-in or
Set this attribute to
trueif the cluster will receive requests from a proxy plug-in or
HttpClusterServlet. A call to
getRemoteAddrwill return the address of the browser client from the proprietary
WL-Proxy-Client-IPheader instead of the Web server.
Set this attribute to
falseto disable the
weblogic-plugin-enabled=false, in the
Note: If you are using Oracle HTTP Server, the WebLogic Proxy Plug-In, or Oracle Traffic Director to distribute client requests to a Managed Server or a cluster, Oracle recommends setting this attribute to
Member Warmup Timeout Seconds
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 discovered. If the value is set 0, servers will not attempt to discover other running server in the cluster during server initialization
Http Trace Support Enabled
Returns the value of HttpTraceSupportEnabled.
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.
Frontend HTTP Port
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.
Frontend HTTPS Port
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.
Idle Periods Until Timeout
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.
Remote Cluster Address
Set the foreign cluster. Cluster infrastructure uses this address to connect to foreign cluster for HTTP Session WAN/MAN failover.
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.
Inter Cluster Comm Link Health Check Interval
If the cluster link between two clusters goes down, a trigger will run periodically to see if the link is restored. The duration is specified in milliseconds.
Job Scheduler Table Name
The table name to use for storing timers active with the job scheduler
Persist Sessions On Shutdown
When shutting down servers, sessions are not updated. If the primary and secondary servers of a session are shut down with no session updates, the session will be lost. Turning on PersistSessionsOnShutdown will save any active sessions to the database specified in ClusterMBean#getDataSourceForSessionPersistence() when a server is shutdown. The sessions will not be written at any other time. (For example, they are not saved via this mechanism if there is a server crash.)
This attribute is applicable both to session persistence on server shutdown or session persistence across a WAN.
Rolling upgrade can potentially have a bad interaction with traditional in-memory session replication. As managed servers are shutdown and upgraded, in-memory servlet sessions will be lost if both primary and secondary are rebooted before a new request arrives for the session.
Session Flush Interval
Interval in seconds until HTTP Sessions are periodically flushed to the backup cluster to dump session state on disk.
Session Flush Threshold
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.
Health Check Interval Millis
Interval in milliseconds at which Migratable Servers and Cluster Masters prove their liveness via the database.
Health Check Periods Until Fencing
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.
Fencing Grace Period Millis
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.
Multicast Data Encryption
Enables multicast data to be encrypted. Only the multicast data is encrypted. Multicast header information is not encrypted.
Additional Auto Migration Attempts
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 circuit 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.
Time To Sleep Between Auto Migration Attempts
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.
Replication Timeout Enabled
Indicates if timeout should be applied to session replication calls.
Unicast Discovery Period Millis
The timer period that determines how often other members in the cluster are discovered in unicast messaging scheme. This is not applicable to multicast mode. It applies only to unicast mode.
- Configure clusters
- Assign server instances to clusters
- Configure server migration in a cluster
- Configure cross-cluster replication
- Create dynamic clusters
- Configure elasticity for a dynamic cluster
- Perform on-demand scaling for a dynamic cluster