+1 sounds like a great improvement. > With the re-acquirable resource locks, that problem was solved and thoroughly > tested to be robust.
I haven't been able to follow the PIP 45 work, so I have some high level questions. Do we have documentation on the implementation of these re-acquirable resource locks? I'd like to understand how these work. Also, are you able to describe the thorough testing? Were these tests manual or are they already part of our GitHub CI or both? Thanks, Michael On Tue, Dec 14, 2021 at 12:03 PM Matteo Merli <mme...@apache.org> wrote: > > 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>
