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Steve Rowe commented on ZOOKEEPER-2383: --------------------------------------- FWIW, I was able to work around the problem in Solr tests by subclassing ZooKeeperServer and ordering server JMX registration before setting up its request processing pipeline, like so: {code:java} private class TestZooKeeperServer extends ZooKeeperServer { @Override protected void registerJMX() { // no-op - super.registerJMX() is called in overridden startup() } /** Register in JMX before starting the request processors. */ @Override public void startup() { super.registerJMX(); super.startup(); } public TestZooKeeperServer(FileTxnSnapLog txnLogFactory, int tickTime, int minSessionTimeout, int maxSessionTimeout, DataTreeBuilder treeBuilder, ZKDatabase zkDb) { super(txnLogFactory, tickTime, minSessionTimeout, maxSessionTimeout, treeBuilder, zkDb); } } {code} > Startup race in ZooKeeperServer > ------------------------------- > > Key: ZOOKEEPER-2383 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2383 > Project: ZooKeeper > Issue Type: Bug > Components: jmx, server > Affects Versions: 3.4.8 > Reporter: Steve Rowe > Priority: Blocker > Fix For: 3.4.9 > > Attachments: TestZkStandaloneJMXRegistrationRaceConcurrent.java, > release-3.4.8-extra-logging.patch, zk-3.4.8-MBeanRegistry.log, > zk-3.4.8-NPE.log > > > In attempting to upgrade Solr's ZooKeeper dependency from 3.4.6 to 3.4.8 > (SOLR-8724) I ran into test failures where attempts to create a node in a > newly started standalone ZooKeeperServer were failing because of an assertion > in MBeanRegistry. > ZooKeeperServer.startup() first sets up its request processor chain then > registers itself in JMX, but if a connection comes in before the server's JMX > registration happens, registration of the connection will fail because it > trips the assertion that (effectively) its parent (the server) has already > registered itself. > {code:java|title=ZooKeeperServer.java} > public synchronized void startup() { > if (sessionTracker == null) { > createSessionTracker(); > } > startSessionTracker(); > setupRequestProcessors(); > registerJMX(); > state = State.RUNNING; > notifyAll(); > } > {code} > {code:java|title=MBeanRegistry.java} > public void register(ZKMBeanInfo bean, ZKMBeanInfo parent) > throws JMException > { > assert bean != null; > String path = null; > if (parent != null) { > path = mapBean2Path.get(parent); > assert path != null; > } > {code} > This problem appears to be new with ZK 3.4.8 - AFAIK Solr never had this > issue with ZK 3.4.6. -- This message was sent by Atlassian JIRA (v6.3.4#6332)