+1 Thanks, Hang
PengHui Li <peng...@apache.org> 于2021年12月22日周三 19:34写道： > > +1 > > Penghui > > On Wed, Dec 22, 2021 at 7:22 AM Matteo Merli <mme...@apache.org> wrote: > > > https://github.com/apache/pulsar/issues/13304 > > > > Following the discussion, I have updated the proposal to also include > > the deprecation and renaming of the config setting name to > > `metadataSessionExpiredPolicy`. > > > > > > > > ------- > > ## 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 to stabilize 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 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 > > ``` > > > > Deprecate the old setting and rename it to > > `metadataSessionExpiredPolicy`, with default value set to `reconnect`. > >
