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https://issues.apache.org/jira/browse/BOOKKEEPER-281?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13288487#comment-13288487
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Ivan Kelly commented on BOOKKEEPER-281:
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Regarding state notifications, I think this is a bad idea. A user of the api
shouldn't need to know if the client is ready to use or not. They should be
able to just submit an async request to the client, and either the client does
it and completes with success or failure due to an unrecoverable error state.
The user isn't going to check the state and, on seeing that the client isn't
connected, decide that it doesn't want to add an entry. My biggest problem with
the ZooKeeper api is that it doesn't allow a user to submit an async request
without having to ensure that its in connected state. The api is supposed to
hide these kind of details. In fact, the HBase guys wrapped the whole zookeeper
api to get around this problem[1]. I think, in 4.2 we should perhaps take a
similar approach.
[1]
https://github.com/apache/hbase/blob/trunk/hbase-server/src/main/java/org/apache/hadoop/hbase/zookeeper/RecoverableZooKeeper.java
> BKClient is failing when zkclient connection delays
> ---------------------------------------------------
>
> Key: BOOKKEEPER-281
> URL: https://issues.apache.org/jira/browse/BOOKKEEPER-281
> Project: Bookkeeper
> Issue Type: Bug
> Reporter: Ivan Kelly
> Assignee: Ivan Kelly
> Fix For: 4.1.0, 4.2.0
>
> Attachments: BOOKKEEPER-281.diff, BOOKKEEPER-281.diff,
> BOOKKEEPER-281.diff
>
>
> I have started the ZK cluster and when tries to create a BookKeeper client
> from my application, it is throwing following ZooKeeper
> ConnectionLossException and is exitting.
> 12/06/01 11:44:31 WARN client.ZooKeeperSaslClient: SecurityException:
> java.lang.SecurityException: Unable to locate a login configuration occurred
> when trying to find JAAS configuration.
> 12/06/01 11:44:31 INFO client.ZooKeeperSaslClient: Client will not
> SASL-authenticate because the default JAAS configuration section 'Client'
> could not be found. If you are not using SASL, you may ignore this. On the
> other hand, if you expected SASL to work, please fix your JAAS configuration.
> 12/06/01 11:44:31 INFO zookeeper.ClientCnxn: Client session timed out, have
> not heard from server in 4540ms for sessionid 0x0, closing socket connection
> and attempting reconnect
> 12/06/01 11:44:32 INFO zookeeper.ClientCnxn: Opening socket connection to
> server /10.18.40.91:2182
> Exception in thread "main"
> org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode
> = ConnectionLoss
> at org.apache.zookeeper.KeeperException.create(KeeperException.java:99)
> at
> org.apache.bookkeeper.client.BookieWatcher.readBookiesBlocking(BookieWatcher.java:151)
> at org.apache.bookkeeper.client.BookKeeper.<init>(BookKeeper.java:139)
> at BKClient1.main(BKClient1.java:40)
> 12/06/01 11:44:36 WARN client.ZooKeeperSaslClient: SecurityException:
> java.lang.SecurityException: Unable to locate a login configuration occurred
> when trying to find JAAS configuration.
> When analyzed more, the root cause is:
> BookKeeper.java:
> --------------------
> In the constructor of BookKeeper, immediately after creating the ZK client ,
> it is going to bookieWatcher.readBookiesBlocking() for available bookies from
> ZK server before reaching SyncConnected event.
> I think, we would properly use the existing countdown latch and wait till
> ZooKeeper client connection establishment before continue reading Bookies.
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