https://github.com/apache/pulsar/issues/13304
Pasted below for quoting convenience. ------- ## Motivation After all the work done for PIP-45 that was already included in 2.8 and 2.9 releases, it enabled the concept of re-acquirable resource locks and leader election. Another important change was to avoid doing any deferrable metadata operation when we know that we are not currently connected to the metadata service. Finally, that enabled stabilization in 2.9 the configuration setting that allows brokers to continue operating in a safe mode when the session with ZooKeeper expires. The way it works is that, when we lose a ZooKeeper session, the data plane will continue to work undisturbed, relying on the BookKeeper fencing to avoid any inconsistencies. New topics are not able to get started, but existing topics will see no impact. The original intention for shutting down the brokers was to ensure that we would automatically go back to a consistent state, with respect to which resources are "owned" in ZooKeeper by a given broker. With the re-acquirable resource locks, that problem was solved and thoroughly tested to be robust. ## Proposed changes In 2.10 release, for the setting: ```properties # There are two policies to apply when a broker metadata session expires: session expired happens, "shutdown" or "reconnect". # With "shutdown", the broker will be restarted. # With "reconnect", the broker will keep serving the topics, while attempting to recreate a new session. zookeeperSessionExpiredPolicy=shutdown ``` Change its default value to `reconnect`. -- Matteo Merli <mme...@apache.org>
