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https://issues.apache.org/jira/browse/CURATOR-392?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16083584#comment-16083584
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ASF GitHub Bot commented on CURATOR-392:
----------------------------------------
Github user Vile2539 commented on the issue:
https://github.com/apache/curator/pull/205
It's been about 4 months, so I'm a bit fuzzy on the exact details.
> The spec of server address is server. = ::[:role];[:], and if
server.clientAddr is null then it means the client port address is not present.
The client port address is optional, so the address is still a valid address.
The problem is that EnsembleTracker is getting the connection string for
itself to Zookeeper. If it receives a config without a valid client port, then
it can't create a new connection string to that client. Since Zookeeper isn't
sending the clientPort configured outside of that string (in this case), we
can't use any of the connection string.
> I think you can just use server.addr which is guaranteed not null, and
then use getHostAddress to get the hostAddress.
I'm not entirely sure about that. We want to use the server.clientAddr
ideally - unless it's a wildcard, in which case we use the server.addr. It's
not about one of them being null, but the clientAddr should be favoured over
the server.addr (for example - we might have clientAddr set to localhost to
accept only local connections).
> Zookeeper Ensemble Get Incorrect Address
> ----------------------------------------
>
> Key: CURATOR-392
> URL: https://issues.apache.org/jira/browse/CURATOR-392
> Project: Apache Curator
> Issue Type: Bug
> Components: Framework
> Affects Versions: 3.2.1
> Environment: ZooKeeper 3.5.1-alpha
> Reporter: Alex Rankin
>
> I've noticed an issue with Curator 3.2.1 which relates to the fix from
> CURATOR-345 (also reported by me).
> When we would reconnect after losing connection to Zookeeper (due to network
> issues), our services would always have the wrong connection string, and
> never manage to reconnect to the Zookeeper cluster. Assuming that 10.1.2.3 is
> our zookeeper server, and we have two scenarios (with different zoo.cfg
> files) we were seeing the following results when a reconnection was
> established:
> {quote}
> *Scenario 1:* ClientCnxn - Opening socket connection to server
> 0.0.0.0/0.0.0.0:2181.
> *Scenario 2:* ClientCnxn - Opening socket connection to server
> 10.1.2.3/10.1.2.3:2888.
> {quote}
> Obviously these are both undesirable connection strings, as both are wrong.
> The issue arises in the EnsembleTracker.processConfigData() when we reconnect
> to Zookeeper. The config coming from zookeeper is in [the
> format|https://zookeeper.apache.org/doc/trunk/zookeeperReconfig.html#sc_reconfig_clientport]:
> {quote}
> server.<positive id> = <address1>:<port1>:<port2>\[:role\];\[<client port
> address>:\]<client port>
> {quote}
> As we can see, both \[:role\] and \[<client port address>:\] are optional.
> Hence, the following string is perfectly valid:
> {quote}
> server.1=10.1.2.3:2888:3888:participant;2181
> {quote}
> When Zookeeper sends this, it defaults the clientAddress to 0.0.0.0, so we
> retrieve the following value in EnsembleTracker:
> {quote}
> server.1=10.1.2.3:2888:3888:participant;0.0.0.0:2181
> {quote}
> The resulting connection string, therefore, turns in to 0.0.0.0:2181 instead
> of 10.1.2.3:2181, and Curator creates a new ZooKeeper to connect to that IP -
> which obviously never works.
> In the second scenario, our connection string looks a bit different. It is
> wrong according to the docs, but is valid:
> {quote}
> server.1=10.1.2.3:2888:3888:participant
> {quote}
> Now, this is missing the client port and address. That means that the
> resulting string from the EnsembleTracker is 10.1.2.3:2888 - which isn't
> desired. Including the port would just lead to the above scenario.
> From what I can see, the EnsembleTracker.configToConnectionString() method is
> the issue here:
> {code}
> InetSocketAddress address = Objects.firstNonNull(server.clientAddr,
> server.addr);
>
> sb.append(address.getAddress().getHostAddress()).append(":").append(address.getPort());
> {code}
> In the above cases, both the server.Addr and server.clientAddr values are
> wrong. We also prefer the value of clientAddr for some reason, which doesn't
> look right to me (given that it can be 0.0.0.0 or 127.0.0.1).
> It seems to me that Curator should use server.Addr.getHostAddress() with
> server.clientAddr.getPort(). When the clientAddr is missing, however, I'm not
> sure what should be done.
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