Leasing and Automatic Migration
WebLogic Server ensures that singleton services such as JMS services run only on a single server in a cluster any time by using the concept of leasing, which ensures that only one instance in the cluster owns a service. The key point about a lease is that the owner must periodically renew the lease. Failure to renew the lease allows someone else to “take it over.” When the original owner comes back on line, it will in turn try to “renew” the lease but will find that someone else now owns it. This is how leasing ensures that only one virtual machine (JVM) is running the service at a time.
There can only be a single lease owner for a resource, and the lease can fail over during a failure, ensuring that the pinned ...
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