-These release notes include new developer and user facing incompatibilities, features, and major improvements. -
- - --Changes -
-- -You should only have to read this section if you are upgrading from a previous version of ZooKeeper to version 3.0.0, otw skip down to changes - -
--A small number of changes in this release have resulted in non-backward compatible Zookeeper client user code and server instance data. The following instructions provide details on how to migrate code and date from version 2.2.1 to version 3.0.0. -
--Note: ZooKeeper increments the major version number (major.minor.fix) when backward incompatible changes are made to the source base. As part of the migration from SourceForge we changed the package structure (com.yahoo.zookeeper.* to org.apache.zookeeper.*) and felt it was a good time to incorporate some changes that we had been withholding. As a result the following will be required when migrating from 2.2.1 to 3.0.0 version of ZooKeeper. -
-- The underlying client-server protocol has changed in version 3.0.0 - of ZooKeeper. As a result clients must be upgraded along with - serving clusters to ensure proper operation of the system (old - pre-3.0.0 clients are not guaranteed to operate against upgraded - 3.0.0 servers and vice-versa). -
- --In previous releases of ZooKeeper any watches registered by clients were lost if the client lost a connection to a ZooKeeper server. -This meant that developers had to track watches they were interested in and reregister them if a session disconnect event was recieved. -In this release the client library tracks watches that a client has registered and reregisters the watches when a connection is made to a new server. -Applications that still manually reregister interest should continue working properly as long as they are able to handle unsolicited watches. -For example, an old application may register a watch for /foo and /goo, lose the connection, and reregister only /goo. -As long as the application is able to recieve a notification for /foo, (probably ignoring it) the applications does not to be changes. -One caveat to the watch management: it is possible to miss an event for the creation and deletion of a znode if watching for creation and both the create and delete happens while the client is disconnected from ZooKeeper. -
--This release also allows clients to specify call specific watch functions. -This gives the developer the ability to modularize logic in different watch functions rather than cramming everything in the watch function attached to the ZooKeeper handle. -Call specific watch functions receive all session events for as long as they are active, but will only receive the watch callbacks for which they are registered. -
- -The java package structure has changed from com.yahoo.zookeeper* to org.apache.zookeeper*. This will probably effect all of your java code which makes use of ZooKeeper APIs (typically import statements)
-A number of constants used in the client ZooKeeper API were re-specified using enums (rather than ints). See ZOOKEEPER-7, ZOOKEEPER-132 and ZOOKEEPER-139 for full details
--ZOOKEEPER-18 removed KeeperStateChanged, use KeeperStateDisconnected instead
--Also see the current java API - -
- -A number of constants used in the client ZooKeeper API were renamed in order to reduce namespace collision, see ZOOKEEPER-6 for full details
--The following issues resulted in changes to the on-disk data format (the snapshot and transaction log files contained within the ZK data directory) and require a migration utility to be run. -
--ZOOKEEPER-27 Unique DB identifiers for servers and clients -
-- -The following must be run once, and only once, when upgrading the ZooKeeper server instances to version 3.0.0. - +These release notes include new developer and user facing +incompatibilities, features, and major improvements.
-- The <dataLogDir> and <dataDir> directories referenced - below are specified by the dataLogDir - and dataDir specification in your - ZooKeeper config file - respectively. dataLogDir defaults to the - value of dataDir if not specified explicitly - in the ZooKeeper server config file (in which case provide the - same directory for both parameters to the upgrade utility). -
-Shutdown the ZooKeeper server cluster.
-Backup your <dataLogDir> and <dataDir> directories
-Run upgrade using
- --bin/zkServer.sh upgrade <dataLogDir> <dataDir> -
-or
- --java -classpath pathtolog4j:pathtozookeeper.jar UpgradeMain <dataLogDir> <dataDir> -
-where <dataLogDir> is the directory where all transaction logs (log.*) are stored. <dataDir> is the directory where all the snapshots (snapshot.*) are stored.
- -Restart the cluster.
-- If you have any failure during the upgrade procedure keep reading to sanitize your database. -
-This is how upgrade works in ZooKeeper. This will help you troubleshoot in case you have problems while upgrading
-Upgrade moves files from <dataLogDir> and <dataDir> to <dataLogDir>/version-1/ and <dataDir>/version-1 respectively (version-1 sub-directory is created by the upgrade utility).
-Upgrade creates a new version sub-directory <dataDir>/version-2 and <dataLogDir>/version-2
-Upgrade reads the old database from <dataDir>/version-1 and <dataLogDir>/version-1 into the memory and creates a new upgraded snapshot.
-Upgrade writes the new database in <dataDir>/version-2.
-Troubleshooting.
-In case you start ZooKeeper 3.0 without upgrading from 2.0 on a 2.0 database - the servers will start up with an empty database. - This is because the servers assume that <dataDir>/version-2 and <dataLogDir>/version-2 will have the database to start with. Since this will be empty - in case of no upgrade, the servers will start with an empty database. In such a case, shutdown the ZooKeeper servers, remove the version-2 directory (remember - this will lead to loss of updates after you started 3.0.) - and then start the upgrade procedure.
-If the upgrade fails while trying to rename files into the version-1 directory, you should try and move all the files under <dataDir>/version-1 - and <dataLogDir>/version-1 to <dataDir> and <dataLogDir> respectively. Then try upgrade again. -
- -If you do not wish to run with ZooKeeper 3.0 and prefer to run with ZooKeeper 2.0 and have already upgraded - you can run ZooKeeper 2 with - the <dataDir> and <dataLogDir> directories changed to <dataDir>/version-1 and <dataLogDir>/version-1. Remember that you will lose all the updates that you made after the upgrade. -
--There is a significant change to the ZooKeeper server configuration file. -
-The default election algorithm, specified by - the electionAlg configuration attribute, has - changed from a default of 0 to a default - of 3. See - Cluster - Options section of the administrators guide, specifically - the electionAlg - and server.X properties. -
-- You will either need to explicitly - set electionAlg to it's previous default value - of 0 or change - your server.X options to include the leader - election port. -
-See 3.0 +release notes and migration instructions if you are upgrading +from version 2 of ZooKeeper (SourceForge) to version 3 or +later.
- --Version 2.2.1 code, documentation, binaries, etc... are still accessible on SourceForge - -
| - - ZOOKEEPER-43 - | -- Server side of auto reset watches. - | - -||
| - - ZOOKEEPER-132 - | -- Create Enum to replace CreateFlag in ZooKepper.create method - | - -||
| - - ZOOKEEPER-139 - | -- Create Enums for WatcherEvent's KeeperState and EventType - | - -||
| - - ZOOKEEPER-18 - | -- keeper state inconsistency - | - -||
| - - ZOOKEEPER-38 - | -- headers in log/snap files - | - -||
| - - ZOOKEEPER-8 - | -- Stat enchaned to include num of children and size - | - -||
| - - ZOOKEEPER-6 - | -- List of problem identifiers in zookeeper.h - | - -||
| - - ZOOKEEPER-7 - | -- Use enums rather than ints for types and state - | - -||
| - - ZOOKEEPER-27 - | -- Unique DB identifiers for servers and clients - | - -||
| - - ZOOKEEPER-32 - | -- CRCs for ZooKeeper data - | - -||
| - - ZOOKEEPER-33 - | -- Better ACL management - | - -||
| - - ZOOKEEPER-203 - | -- fix datadir typo in releasenotes - | +Incompatibilities | +|
| - - ZOOKEEPER-145 - | -- write detailed release notes for users migrating from 2.x to 3.0 - | - +ZOOKEEPER-255 | zoo_set() api does not return stat datastructure. + |
| - - ZOOKEEPER-23 - | -- Auto reset of watches on reconnect - | - -||
| - - ZOOKEEPER-191 - | -- forrest docs for upgrade. - | +New Feature | +|
| - - ZOOKEEPER-201 - | -- validate magic number when reading snapshot and transaction logs - | - +ZOOKEEPER-135 | Fat jar build target + |
| - - ZOOKEEPER-200 - | -- the magic number for snapshot and log must be different - | - +ZOOKEEPER-215 | expand system test environment + |
| - - ZOOKEEPER-199 - | -- fix log messages in persistence code - | - +ZOOKEEPER-231 | Quotas in zookeeper + |
| - - ZOOKEEPER-197 - | -- create checksums for snapshots - | - +ZOOKEEPER-256 | support use of JMX to manage log4j configuration at runtime + |
| - - ZOOKEEPER-198 - | -- apache license header missing from FollowerSyncRequest.java - | - +ZOOKEEPER-276 | Bookkeeper contribution + |
| - - ZOOKEEPER-5 - | -- Upgrade Feature in Zookeeper server. - | +Task | +|
| - - ZOOKEEPER-194 - | -- Fix terminology in zookeeperAdmin.xml - | - -||
| - - ZOOKEEPER-151 - | -- Document change to server configuration - | - -||
| - - ZOOKEEPER-193 - | -- update java example doc to compile with latest zookeeper - | - -||
| - - ZOOKEEPER-187 - | -- CreateMode api docs missing - | - -||
| - - ZOOKEEPER-186 - | -- add new "releasenotes.xml" to forrest documentation - | - -||
| - - ZOOKEEPER-190 - | -- Reorg links to docs and navs to docs into related sections - | - -||
| - - ZOOKEEPER-189 - | -- forrest build not validated xml of input documents - | - -||
| - - ZOOKEEPER-188 - | -- Check that election port is present for all servers - | - -||
| - - ZOOKEEPER-185 - | -- Improved version of FLETest - | - -||
| - - ZOOKEEPER-184 - | -- tests: An explicit include derective is needed for the usage of memcpy functions - | - -||
| - - ZOOKEEPER-183 - | -- Array subscript is above array bounds in od_completion, src/cli.c. - | - -||
| - - ZOOKEEPER-182 - | -- zookeeper_init accepts empty host-port string and returns valid pointer to zhandle_t. - | - +ZOOKEEPER-210 | Require Java 6 + |
| - - ZOOKEEPER-17 - | -- zookeeper_init doc needs clarification - | +Bug | +|
| - - ZOOKEEPER-181 - | -- Some Source Forge Documents did not get moved over: javaExample, zookeeperTutorial, zookeeperInternals - | - +ZOOKEEPER-16 | Need to do path validation + |
| - - ZOOKEEPER-180 - | -- Placeholder sections needed in document for new topics that the umbrella jira discusses - | - +ZOOKEEPER-204 | SetWatches needs to be the first message after auth messages to the server + |
| - - ZOOKEEPER-179 - | -- Programmer's Guide "Basic Operations" section is missing content - | - +ZOOKEEPER-205 | Error on version-info when compiling from the tarball distribution + |
| - - ZOOKEEPER-178 - | -- FLE test. - | - +ZOOKEEPER-206 | documentation tab should contain the version number (and other small site changes) + |
| - - ZOOKEEPER-159 - | -- Cover two corner cases of leader election - | - +ZOOKEEPER-208 | Zookeeper C client uses API that are not thread safe, causing crashes when multiple instances are active + |
| - - ZOOKEEPER-156 - | -- update programmer guide with acl details from old wiki page - | - +ZOOKEEPER-209 | nullpointerexception if election port is not specified. + |
| - - ZOOKEEPER-154 - | -- reliability graph diagram in overview doc needs context - | - +ZOOKEEPER-212 | snapshot is synchronous in 3.0 + |
| - - ZOOKEEPER-157 - | -- Peer can't find existing leader - | - +ZOOKEEPER-213 | programmer guide C api docs are out of sync with latest zookeeper.h + |
| - - ZOOKEEPER-155 - | -- improve "the zookeeper project" section of overview doc - | - +ZOOKEEPER-218 | error in barrier recipe example code + |
| - - ZOOKEEPER-140 - | -- Deadlock in QuorumCnxManager - | - +ZOOKEEPER-219 | events.poll timeout in watcher test too short + |
| - - ZOOKEEPER-147 - | -- This is version of the documents with most of the [tbd...] scrubbed out - | - +ZOOKEEPER-221 | log message in ZkWatchManager.materialize missing conditional + |
| - - ZOOKEEPER-150 - | -- zookeeper build broken - | - +ZOOKEEPER-226 | exists calls fails on server if node has null data + |
| - - ZOOKEEPER-136 - | -- sync causes hang in all followers of quorum. - | - +ZOOKEEPER-227 | gcc warning from recordio.h + |
| - - ZOOKEEPER-134 - | -- findbugs cleanup - | - +ZOOKEEPER-228 | apache header missing in DBtest + |
| - - ZOOKEEPER-133 - | -- hudson tests failing intermittently - | - +ZOOKEEPER-232 | testablezookeeper file is missing apache licence headers. + |
| - - ZOOKEEPER-144 - | -- add tostring support for watcher event, and enums for event type/state - | - +ZOOKEEPER-240 | Yet another npe + |
| - - ZOOKEEPER-21 - | -- Improve zk ctor/watcher - | - +ZOOKEEPER-241 | Build of a distro fails after clean target is run + |
| - - ZOOKEEPER-142 - | -- Provide Javadoc as to the maximum size of the data byte array that may be stored within a znode - | - +ZOOKEEPER-242 | zookeeper c tests are faliling.. + |
| - - ZOOKEEPER-93 - | -- Create Documentation for Zookeeper - | - +ZOOKEEPER-245 | update readme/quickstart to be release tar, rather than source, based + |
| - - ZOOKEEPER-117 - | -- threading issues in Leader election - | - +ZOOKEEPER-247 | fix formatting of C API in ACL section of programmer guide + |
| - - ZOOKEEPER-137 - | -- client watcher objects can lose events - | - +ZOOKEEPER-249 | QuorumPeer.getClientPort() always returns -1 + |
| - - ZOOKEEPER-131 - | -- Old leader election can elect a dead leader over and over again - | - +ZOOKEEPER-250 | isvalidsnapshot should handle the case of 0 snapshot files better. + |
| - - ZOOKEEPER-130 - | -- update build.xml to support apache release process - | - +ZOOKEEPER-251 | NullPointerException stopping and starting Zookeeper servers + |
| - - ZOOKEEPER-118 - | -- findbugs flagged switch statement in followerrequestprocessor.run - | - +ZOOKEEPER-252 | PurgeTxnLog is not handling the new dataDir directory structure + |
| - - ZOOKEEPER-115 - | -- Potential NPE in QuorumCnxManager - | - +ZOOKEEPER-253 | documentation of DataWatcher state transition is misleading regarding auto watch reset on reconnect + |
| - - ZOOKEEPER-114 - | -- cleanup ugly event messages in zookeeper client - | - +ZOOKEEPER-254 | there is currently no way for a user to test session expiration in their code + |
| - - ZOOKEEPER-112 - | -- src/java/main ZooKeeper.java has test code embedded into it. - | - +ZOOKEEPER-257 | Review logging level for WARN/ERROR log messages, some misclassified + |
| - - ZOOKEEPER-39 - | -- Use Watcher objects rather than boolean on read operations. - | - +ZOOKEEPER-258 | docs incorrectly state max client timeout as 60 seconds (it's based on server ticktime) + |
| - - ZOOKEEPER-97 - | -- supports optional output directory in code generator. - | - +ZOOKEEPER-266 | KeeperState missing javadoc for values + |
| - - ZOOKEEPER-101 - | -- Integrate ZooKeeper with "violations" feature on hudson - | - +ZOOKEEPER-267 | java client incorrectly generating syncdisconnected event when in disconnected state + |
| - - ZOOKEEPER-105 - | -- Catch Zookeeper exceptions and print on the stderr. - | - +ZOOKEEPER-268 | tostring on jute generated objects can cause NPE + |
| - - ZOOKEEPER-42 - | -- Change Leader Election to fast tcp. - | - +ZOOKEEPER-272 | getChildren can fail for large numbers of children + |
| - - ZOOKEEPER-48 - | -- auth_id now handled correctly when no auth ids present - | - +ZOOKEEPER-273 | Zookeeper c client build should not depend on CPPUNIT + |
| - - ZOOKEEPER-44 - | -- Create sequence flag children with prefixes of 0's so that they can be lexicographically sorted. - | - +ZOOKEEPER-275 | Bug in FastLeaderElection + |
| - - ZOOKEEPER-108 - | -- Fix sync operation reordering on a Quorum. - | - +ZOOKEEPER-284 | JMX doesn't get the clientPort correctly + |
| - - ZOOKEEPER-25 - | -- Fuse module for Zookeeper. - | - +ZOOKEEPER-285 | the stat command does not return the correct mode + |
| - - ZOOKEEPER-58 - | -- Race condition on ClientCnxn.java - | - -||
| - - ZOOKEEPER-56 - | -- Add clover support to build.xml. - | - -||
| - - ZOOKEEPER-75 - | -- register the ZooKeeper mailing lists with nabble.com - | - -||
| - - ZOOKEEPER-54 - | -- remove sleeps in the tests. - | - -||
| - - ZOOKEEPER-55 - | -- build.xml failes to retrieve a release number from SVN and the ant target "dist" fails - | - -||
| - - ZOOKEEPER-89 - | -- invoke WhenOwnerListener.whenNotOwner when the ZK connection fails - | - -||
| - - ZOOKEEPER-90 - | -- invoke WhenOwnerListener.whenNotOwner when the ZK session expires and the znode is the leader - | - -||
| - - ZOOKEEPER-82 - | -- Make the ZooKeeperServer more DI friendly. - | - -||
| - - ZOOKEEPER-110 - | -- Build script relies on svnant, which is not compatible with subversion 1.5 working copies - | - -||
| - - ZOOKEEPER-111 - | -- Significant cleanup of existing tests. - | - -||
| - - ZOOKEEPER-122 - | -- Fix NPE in jute's Utils.toCSVString. - | - -||
| - - ZOOKEEPER-123 - | -- Fix the wrong class is specified for the logger. - | - -||
| - - ZOOKEEPER-2 - | -- Fix synchronization issues in QuorumPeer and FastLeader election. - | - -||
| - - ZOOKEEPER-125 - | -- Remove unwanted class declaration in FastLeaderElection. - | - +ZOOKEEPER-211 | Not all Mock tests are working + |
| - - ZOOKEEPER-61 - | -- Address in client/server test cases. - | +Improvement | +|
| - - ZOOKEEPER-75 - | -- cleanup the library directory - | - +ZOOKEEPER-64 | We should log system env information when intializing client/server + |
| - - ZOOKEEPER-109 - | -- cleanup of NPE and Resource issue nits found by static analysis - | - +ZOOKEEPER-149 | c interface is missing tests against java server (mock only) + |
| - - ZOOKEEPER-76 - | -- Commit 677109 removed the cobertura library, but not the build targets. - | - +ZOOKEEPER-177 | needed: docs for JMX + |
| - - ZOOKEEPER-63 - | -- Race condition in client close - | - +ZOOKEEPER-214 | add new "stat reset" command to server admin port + |
| - - ZOOKEEPER-70 - | -- Add skeleton forrest doc structure for ZooKeeper - | - +ZOOKEEPER-217 | handle errors when parsing config file, throw illegalargumentexception rather than exit() + |
| - - ZOOKEEPER-79 - | -- Document jacob's leader election on the wiki recipes page - | - +ZOOKEEPER-220 | programming guide watches section should clarify server/clientlib role in data/child watch maint. + |
| - - ZOOKEEPER-73 - | -- Move ZK wiki from SourceForge to Apache - | - +ZOOKEEPER-222 | print C client log message timestamp in human readable form + |
| - - ZOOKEEPER-72 - | -- Initial creation/setup of ZooKeeper ASF site. - | - +ZOOKEEPER-223 | default log4j root logger configuration has neg perf impact with no benefit, change default level to INFO + |
| - - ZOOKEEPER-71 - | -- Determine what to do re ZooKeeper Changelog - | - +ZOOKEEPER-225 | c client should log an info message in zookeeper_init detailing connection parameters + |
| - - ZOOKEEPER-68 - | -- parseACLs in ZooKeeper.java fails to parse elements of ACL, should be lastIndexOf rather than IndexOf - | - +ZOOKEEPER-229 | improve documentation regarding user's responsibility to cleanup datadir (snaps/logs) + |
| - - ZOOKEEPER-130 - | -- update build.xml to support apache release process. - | - +ZOOKEEPER-230 | Improvements to FLE + |
| - - ZOOKEEPER-131 - | -- Fix Old leader election can elect a dead leader over and over again. - | - +ZOOKEEPER-234 | Eliminate using statics to initialize the sever. Should allow server to be more embeddable in OSGi enviorments. + |
| - - ZOOKEEPER-137 - | -- client watcher objects can lose events - | - +ZOOKEEPER-243 | add SEQUENCE flag documentation to the programming guide + |
| - - ZOOKEEPER-117 - | -- threading issues in Leader election - | - +ZOOKEEPER-246 | review error code definition in both source and docs + |
| - - ZOOKEEPER-128 - | -- test coverage on async client operations needs to be improved - | - +ZOOKEEPER-248 | QuorumPeer should use Map interface instead of HashMap implementation. + |
| - - ZOOKEEPER-127 - | -- Use of non-standard election ports in config breaks services - | - +ZOOKEEPER-259 | cleanup the logging levels used (use the correct level) and messages generated + |
| - - ZOOKEEPER-53 - | -- tests failing on solaris. - | - -||
| - - ZOOKEEPER-172 - | -- FLE Test - | - -||
| - - ZOOKEEPER-41 - | -- Sample startup script - | - +ZOOKEEPER-260 | document the recommended values for server id's + |
| - - ZOOKEEPER-33 - | -- Better ACL management - | - +ZOOKEEPER-263 | document connection host:port as comma separated list in forrest docs + |
| - - ZOOKEEPER-49 - | -- SetACL does not work - | - +ZOOKEEPER-265 | remove (deprecate) unused NoSyncConnected from KeeperState + |
| - - ZOOKEEPER-20 - | -- Child watches are not triggered when the node is deleted - | - +ZOOKEEPER-269 | connectionloss - add more documentation to detail + |
| - - ZOOKEEPER-15 - | -- handle failure better in build.xml:test - | - +ZOOKEEPER-286 | Make GenerateLoad use InstanceContainers + |
| - - ZOOKEEPER-11 - | -- ArrayList is used instead of List - | - +ZOOKEEPER-289 | add debug messages to nioserver select loop. + |
| - - ZOOKEEPER-45 - | -- Restructure the SVN repository after initial import - | - +ZOOKEEPER-161 | Content needed: "Designing a ZooKeeper Deployment" + |
| - - ZOOKEEPER-1 - | -- Initial ZooKeeper code contribution from Yahoo! - | - +ZOOKEEPER-69 | ZooKeeper logo + |