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| Oracle Solaris Cluster Data Service for Oracle WebLogic Server Guide Oracle Solaris Cluster 4.1

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## Operation of the Oracle Solaris Cluster HA for WebLogic Server Fault Monitor

This section describes the Oracle Solaris Cluster HA for WebLogic Server Fault Monitor.

### Probing Algorithm and Functionality

The Fault Monitor detects failures and takes action. If the monitor detects a failure in a WebLogic Server, it first restarts the WebLogic Server. If the WebLogic Server fails a certain number of times (configurable by the administrator) within a certain time window (configurable by the administrator), the resource group containing the WebLogic Server is failed over to another surviving cluster node and restarted.

The Fault Monitor method, by default, probes the server URL set in the extension property `Server_url`. The probe connects to the hostname and the port and then sends an `HTTP GET` request on the URL. If the connection fails, it is considered a complete failure and the resource group containing the WebLogic Server is restarted or failed over to another surviving cluster node and restarted. If the connection succeeds, but the HTTP response code is 500 (internal server error), it is also considered a complete failure and the resource group is restarted or failed over. All other HTTP response codes are considered a success.

If the `monitor_uri_list` extension property is set, the probe method connects to the URIs mentioned in the list and takes action if a failure occurs. The probe sends an `HTTP GET` on the specified URI or URIs.

In a multi-master configuration, the managed server resources have per-node resource dependencies set on the logical host resources. If the `monitor_uri_list` extension property is set, the probing algorithm iterates through the list of URIs and probes only those URIs that match the logical hostname that is online on that particular node. Probing on the rest of the URIs is ignored on that particular node.

For example, if `Monitor_Uri_list=http://log-host-1:7003/abc.asp,http://log-host-2:7003/abc.asp`, and the property `resource_dependencies=log-host-1@node1,log-host-2@node2`, the probe method on Node1 connects to the URI `http://log-host-1:7003/abc.asp` and ignores the URI `http://log-host-2:7003/abc.asp`. The probe method on Node2 connects to the URI `http://log-host-2:7003/abc.asp` and ignores the other URI. The probe method running on each node takes appropriate action if a failure occurs.

Note - The `Monitor_Uri_List` extension property supports HTTP requests only. It does not support HTTPS requests.

If a complete failure (URL or URI probe) of the WebLogic Server instance is detected by the probe, and if a database probe script is specified in the extension property `db_probe_script`, the probe method will probe the database before taking any action on the WebLogic Server resource. If the database probe script returns success (database is up), action is taken on the WebLogic Server resource. If the database probe script returns a failure (database is down), the WebLogic Server probe will not take any action (restart or failover) until the database is up.

#### START Method

Before starting the WebLogic Server that is configured in the resource, the WebLogic Server configuration and the resource extension properties are validated. If the `db_probe_script` extension property is set, the database is probed by running the script that is set in the extension property. If the database is up, the WebLogic Server is started by running the START script that is configured in the extension property `Start_script` under `pmf`. If the database is not up, the START method returns success and lets the probe method handle the starting of the WebLogic Server. The probe method waits until the database is up to start the WebLogic Server, as explained in Probing Algorithm and Functionality.

After starting the START script under `pmf`, the START method waits until the WebLogic Server is in RUNNING mode before declaring the START method successful. While waiting for the WebLogic Server to start, the probe method tries to connect to the server to check if it is up. Some messages are displayed on the console during startup. The message “Failed to connect to host logical-host-1 and port 7001: Connection refused” will continue to be displayed until the WebLogic Server starts completely. After the WebLogic Server is in the RUNNING mode, the START method sets the status to “Started Successfully.”

WebLogic Server console messages are stored at `/var/cluster/logs/hawls/wls-resource-name` on the cluster node where the resource is started. You can check this log file for startup messages of WebLogic Server instances.

#### STOP Method

The STOP method stops the WebLogic Server that is configured in the resource. By default, the STOP method kills the WebLogic Server by sending a `SIGKILL` to the WebLogic Server process. If the `smooth_shutdown` extension property is set to TRUE, the STOP method tries to bring down the WebLogic Server instance by running the following command:

    java weblogic.Admin -url hostname:port -username $WLS_USER
    -password $WLS_PW SHUTDOWN

If this command fails, the WebLogic Server is shut down by using `SIGKILL`. Even if the command succeeds, the STOP method sends `SIGKILL` to ensure that the WebLogic Server process is stopped.

If the `smooth_shutdown` extension property is set to TRUE, ensure that the `boot.properties` file with valid user name and password is present in the `DOMAIN` directory. The WebLogic Server variables, `WLS_USER` and `WLS_PW` do not need to be set in the START script for smooth shutdown. This waiver applies only to WebLogic Server 8.1 or later versions.

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