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Posted to common-dev@hadoop.apache.org by "Yuri Pradkin (JIRA)" <ji...@apache.org> on 2008/04/08 21:39:24 UTC
[jira] Created: (HADOOP-3212) null pointer exception while
accessing secondaryname web interface (servlet dfshealth.jsp should not be
served from the
secondary Namenode)
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null pointer exception while accessing secondaryname web interface (servlet dfshealth.jsp should not be served from the
secondary Namenode)
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Key: HADOOP-3212
URL: https://issues.apache.org/jira/browse/HADOOP-3212
Project: Hadoop Core
Issue Type: Bug
Components: dfs
Affects Versions: 0.16.2
Environment: Hadoop 0.16.2, and before
Reporter: Yuri Pradkin
Priority: Minor
when I go to the secondary namenode HTTP (dfs.secondary.http.address) in
my browser I see something like this:
HTTP ERROR: 500
init
RequestURI=/dfshealth.jsp
Powered by Jetty://
And in secondary's log I find these lines:
2008-04-02 11:26:25,357 WARN /: /dfshealth.jsp:
java.lang.NullPointerException
at org.apache.hadoop.dfs.dfshealth_jsp.<init>(dfshealth_jsp.java:21)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:539)
at java.lang.Class.newInstance0(Class.java:373)
at java.lang.Class.newInstance(Class.java:326)
at org.mortbay.jetty.servlet.Holder.newInstance(Holder.java:199)
at org.mortbay.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:326)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:405)
at org.mortbay.jetty.servlet.WebApplicationHandler.dispatch(WebApplicationHandler.java:475)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:567)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1565)
at org.mortbay.jetty.servlet.WebApplicationContext.handle(WebApplicationContext.java:635)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1517)
at org.mortbay.http.HttpServer.service(HttpServer.java:954)
at org.mortbay.http.HttpConnection.service(HttpConnection.java:814)
at org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:981)
at org.mortbay.http.HttpConnection.handle(HttpConnection.java:831)
at org.mortbay.http.SocketListener.handleConnection(SocketListener.java:244)
at org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:357)
at org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:534)
Responses from core-user@hadoop.apache.org:
------------
"dhruba Borthakur":
The secondary Namenode uses the HTTP interface to pull the fsimage from
the primary. Similarly, the primary Namenode uses the
dfs.secondary.http.address to pull the checkpointed-fsimage back from
the secondary to the primary. So, the definition of
dfs.secondary.http.address is needed.
However, the servlet dfshealth.jsp should not be served from the
secondary Namenode. This servet should be setup in such a way that only
the primary Namenode invokes this servlet.
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Konstantin Shvachko:
We do not have any secondary nn web interface as of today.
The http server is used for transferring data between the primary and the secondary.
I don't see we can display anything useful on the secondary web UI except for the
current status, config values, and the last checkpoint date/time.
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