Database Reference
In-Depth Information
Further Reading
For more in-depth information about ZooKeeper, see
ZooKeeper
by Flavio Junqueira and
Benjamin Reed (O'Reilly, 2013).
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This is the message of Jim Waldo et al. in
“A Note on Distributed Computing”
(Sun Microsystems,
November 1994). Distributed programming is fundamentally different from local programming, and the dif-
ferences cannot simply be papered over.
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Detailed benchmarks are available in the excellent paper
“ZooKeeper: Wait-free coordination for
Internet-scale systems,”
by Patrick Hunt et al. (USENIX Annual Technology Conference, 2010).
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For a replicated ZooKeeper service, this parameter is the comma-separated list of servers (host and op-
tional port) in the ensemble.
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It is conventional (but not required) to have a trailing dash on pathnames for sequential nodes, to make
their sequence numbers easy to read and parse (by the application).
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Except for callbacks for connection events, which do not need reregistration.
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Leslie Lamport,
“Paxos Made Simple,”
ACM SIGACT News December 2001.
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Zab is described in Benjamin Reed and Flavio Junqueira's
“A simple totally ordered broadcast pro-
tocol,”
LADIS '08 Proceedings of the 2nd Workshop on Large-Scale Distributed Systems and Middleware,
2008.
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Mike Burrows,
“The Chubby Lock Service for Loosely-Coupled Distributed Systems,”
November 2006.
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It is possible to configure ZooKeeper so that the leader does not accept client connections. In this case,
its only job is to coordinate updates. Do this by setting the
leaderServes
property to
no
. This is recom-
mended for ensembles of more than three servers.
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For more detail, see the excellent article
“Java theory and practice: Dealing with InterruptedException”
by Brian Goetz (IBM, May 2006).
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Another way of writing the code would be to have a single catch block, just for
KeeperException
,
and a test to see whether its code has the value
KeeperException.Code.SESSIONEXPIRED
. They
both behave in the same way, so which method you use is simply a matter of style.
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This is discussed in more detail in
“Observers: Making ZooKeeper Scale Even Further”
by Henry
Robinson (Cloudera, December 2009).
