Egor Ryashin created CURATOR-385:
------------------------------------
Summary: Synchronize startup of ExhibitorEnsembleProvider and
Zookeeper connection
Key: CURATOR-385
URL: https://issues.apache.org/jira/browse/CURATOR-385
Project: Apache Curator
Issue Type: Improvement
Components: Client
Affects Versions: 2.10.0
Reporter: Egor Ryashin
Right now starting CuratorFramework with ExhibitorEnsembleProvider could cause
faulty zookeeper connection.
To check this use CuratorFrameworkFactory.Builder and specify
ExhibitorEnsembleProvider.
Call build() and start().
Internal ConnectionState.start() calls ensembleProvider.start() which should
poll for hostnames to produce connectionString.
Without waiting (for connectionString) ConnectionState calls
zooKeeper.closeAndReset() and ClientCnxn is created with empty
connectionString. That leads to lame zooKeeper sending requests to localhost.
{noformat}
2017-01-27T22:56:17,618 INFO [Agents-0]
org.apache.curator.framework.imps.CuratorFrameworkImpl - Starting
2017-01-27T22:56:17,619 INFO [Agents-0] org.apache.zookeeper.ZooKeeper -
Initiating client connection, connectString= sessionTimeout=60001
watcher=org.apache.curator.ConnectionState@4402fad2
2017-01-27T22:56:17,625 INFO [Agents-0-SendThread(127.0.0.1:2181)]
org.apache.zookeeper.ClientCnxn - Opening socket connection to server
127.0.0.1/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown
error)
2017-01-27T22:56:18,632 WARN [Agents-0-SendThread(127.0.0.1:2181)]
org.apache.zookeeper.ClientCnxn - Session 0x0 for server null, unexpected
error, closing socket connection and attempting reconnect
java.net.ConnectException: Connection refused: no further information
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
~[?:1.8.0_74]
at
sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
~[?:1.8.0_74]
at
org.apache.zookeeper.ClientCnxnSocketNIO.doTransport(ClientCnxnSocketNIO.java:350)
~[zookeeper-3.4.5.jar:3.4.5-1392090]
at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1068)
[zookeeper-3.4.5.jar:3.4.5-1392090]
2017-01-27T22:56:19,733 INFO [Agents-0-SendThread(127.0.0.1:2181)]
org.apache.zookeeper.ClientCnxn - Opening socket connection to server
127.0.0.1/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown
error)
2017-01-27T22:56:19,807 INFO [Curator-ExhibitorEnsembleProvider-0]
org.apache.curator.ensemble.exhibitor.ExhibitorEnsembleProvider - Connection
string has changed. Old value (), new value
(172.19.2.158:2181,172.19.2.15:2181,172.19.2.177:2181,172.19.2.4:2181,172.19.2.89:2181,172.19.2.72:2181)
2017-01-27T22:56:20,734 WARN [Agents-0-SendThread(127.0.0.1:2181)]
org.apache.zookeeper.ClientCnxn - Session 0x0 for server null, unexpected
error, closing socket connection and attempting reconnect
java.net.ConnectException: Connection refused: no further information
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
~[?:1.8.0_74]
at
sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
~[?:1.8.0_74]
at
org.apache.zookeeper.ClientCnxnSocketNIO.doTransport(ClientCnxnSocketNIO.java:350)
~[zookeeper-3.4.5.jar:3.4.5-1392090]
at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1068)
[zookeeper-3.4.5.jar:3.4.5-1392090]
2017-01-27T22:56:21,835 INFO [Agents-0-SendThread(127.0.0.1:2181)]
org.apache.zookeeper.ClientCnxn - Opening socket connection to server
127.0.0.1/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown
error)
{noformat}
As a workaround a user could poll for connection string using that provider
beforehand.
The goal of the improvement is to allow user to call CuratorFramework.start()
and got a working framework without an additional poll method call. Using poll
before start() actually uncovers implementation details and is a vague
technique for a general user.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
