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https://issues.apache.org/jira/browse/HADOOP-2185?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Konstantin Shvachko updated HADOOP-2185:
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Attachment: FixedPorts3.patch
Dhruba, thanks for the feedback. I finally realized why the new tests were
sometimes failing.
The problem is with the clients.
Example 1: The name-node instantiates Trash, which creates a DFSClient (even if
trash is disabled).
When the name-node stops this DFSClient remains up and the Secondary name-node
would not start,
because it cannot create a client. Namely the secondary nn just hangs trying to
connect to the
main name-node (RPC.waitForProxy()).
Example 2: Similar thing happens with the JobTracker, which also creates a
DFSClient in order
to remove a file. But never closes it. So the next start of the JobTracker
would hang the same
way as in the previous example.
In both cases if you wait long enough the clients eventually dies, that is why
the failure is
not stable.
I am closing the clients inside my tests now. Closing clients within Trash or
JobTracker breaks
other unit tests, because the clients are static object, and closing a client
once would destroy
that object for everybody else, who opened the client inside the same JVM.
Fixing that is beyond the scope of this patch, I'll open another issue related
to the problem.
All tests pass now.
As I mentioned before, the findBugs warning about assigning to static fields
will remain unfixed.
> Server ports: to roll or not to roll.
> -------------------------------------
>
> Key: HADOOP-2185
> URL: https://issues.apache.org/jira/browse/HADOOP-2185
> Project: Hadoop
> Issue Type: Improvement
> Components: conf, dfs, mapred
> Affects Versions: 0.15.0
> Reporter: Konstantin Shvachko
> Assignee: Konstantin Shvachko
> Fix For: 0.16.0
>
> Attachments: FixedPorts2.patch, FixedPorts3.patch, port.stack
>
>
> Looked at the issues related to port rolling. My impression is that port
> rolling is required only for the unit tests to run.
> Even the name-node port should roll there, which we don't have now, in order
> to be able to start 2 cluster for testing say dist cp.
> For real clusters on the contrary port rolling is not desired and some times
> even prohibited.
> So we should have a way of to ban port rolling. My proposition is to
> # use ephemeral port 0 if port rolling is desired
> # if a specific port is specified then port rolling should not happen at all,
> meaning that a
> server is either able or not able to start on that particular port.
> The desired port is specified via configuration parameters.
> - Name-node: fs.default.name = host:port
> - Data-node: dfs.datanode.port
> - Job-tracker: mapred.job.tracker = host:port
> - Task-tracker: mapred.task.tracker.report.bindAddress = host
> Task-tracker currently does not have an option to specify port, it always
> uses the ephemeral port 0,
> and therefore I propose to add one.
> - Secondary node does not need a port to listen on.
> For info servers we have two sets of config variables *.info.bindAddress and
> *.info.port
> except for the task tracker, which calls them *.http.bindAddress and
> *.http.port instead of "info".
> With respect to the info servers I propose to completely eliminate the port
> parameters, and form
> *.info.bindAddress = host:port
> Info servers should do the same thing, namely start or fail on the specified
> port if it is not 0,
> and start on any free port if it is ephemeral.
> For the task-tracker I would rename tasktracker.http.bindAddress to
> mapred.task.tracker.info.bindAddress
> For the data-node the info dfs.datanode.info.bindAddress should be included
> into the default config.
> Is there a reason why it is not there?
> This is the summary of proposed changes:
> || Server || current name = value || proposed name = value ||
> | NameNode | fs.default.name = host:port | same |
> | | dfs.info.bindAddress = host | dfs.http.bindAddress = host:port |
> | DataNode | dfs.datanode.bindAddress = host | dfs.datanode.bindAddress =
> host:port |
> | | dfs.datanode.port = port | eliminate |
> | | dfs.datanode.info.bindAddress = host | dfs.datanode.http.bindAddress =
> host:port |
> | | dfs.datanode.info.port = port | eliminate |
> | JobTracker | mapred.job.tracker = host:port | same |
> | | mapred.job.tracker.info.bindAddress = host |
> mapred.job.tracker.http.bindAddress = host:port |
> | | mapred.job.tracker.info.port = port | eliminate |
> | TaskTracker | mapred.task.tracker.report.bindAddress = host |
> mapred.task.tracker.report.bindAddress = host:port |
> | | tasktracker.http.bindAddress = host |
> mapred.task.tracker.http.bindAddress = host:port |
> | | tasktracker.http.port = port | eliminate |
> | SecondaryNameNode | dfs.secondary.info.bindAddress = host |
> dfs.secondary.http.bindAddress = host:port |
> | | dfs.secondary.info.port = port | eliminate |
> Do we also want to set some uniform naming convention for the configuration
> variables?
> Like having hdfs instead of dfs, or info instead of http, or systematically
> using either datanode
> or data.node would make that look better in my opinion.
> So these are all +*api*+ changes. I would +*really*+ like some feedback on
> this, especially from
> people who deal with configuration issues on practice.
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