(csdn内转载)Hadoop状态页面的Browse the filesystem链接无效的问题

NameNode '192.168.1.164:9000'

Started:	Tue Jul 06 14:37:10 CST 2010
Version:	0.20.2, r911707
Compiled:	Fri Feb 19 08:07:34 UTC 2010 by chrisdo
Upgrades:	There are no upgrades in progress.

Browse the filesystem
Namenode Logs

Cluster Summary

4 files and directories, 1 blocks = 5 total. Heap Size is 16.12 MB / 888.94 MB (1%)

Configured Capacity	:	1.59 TB
DFS Used	:	72 KB
Non DFS Used	:	120.87 GB
DFS Remaining	:	1.47 TB
DFS Used%	:	0 %
DFS Remaining%	:	92.57 %
Live Nodes	:	2
Dead Nodes	:	0

NameNode Storage:

Storage Directory	Type	State
/opt/hadoop/data/dfs.name.dir	IMAGE_AND_EDITS	Active

 

Hadoop, 2010.

 

　　以上是我们安装完成，并且正常运行后的HDFS状态页面（访问地址：http://210.66.44.88:50070/dfshealth.jsp），其中的Browse the filesystem是查看文件系统的入口，但是有可能会出现无法访问的问题，我就遇到过，上网查了很久的解决办法都无果，后来我通过firebug拦截请求发现，Browse the filesystem这个链接的页面会跳转到另外一个页面，而这个页面的地址是http://192.168.1.164:50075/browseDirectory.jsp?namenodeInfoPort=50070&dir=%2F（192.168.1.164是服务器的内网地址，在masters和slaves文件中配置的是局域网IP），但是需要通过外网才能访问（类似于http://210.66.44.88:50075/browseDirectory.jsp?namenodeInfoPort=50070&dir=%2F才行），这就是问题所在。

　　我们来看看nn_browsedfscontent.jsp的源代码：

    package org.apache.hadoop.hdfs.server.namenode;   
      
    import java.io.IOException;   
    import java.net.InetAddress;   
    import java.net.InetSocketAddress;   
    import java.net.URLEncoder;   
    import java.util.Vector;   
    import javax.servlet.ServletConfig;   
    import javax.servlet.ServletContext;   
    import javax.servlet.ServletException;   
    import javax.servlet.http.HttpServletRequest;   
    import javax.servlet.http.HttpServletResponse;   
    import javax.servlet.http.HttpSession;   
    import javax.servlet.jsp.JspFactory;   
    import javax.servlet.jsp.JspWriter;   
    import javax.servlet.jsp.PageContext;   
    import javax.servlet.jsp.SkipPageException;   
    import org.apache.hadoop.util.ServletUtil;   
    import org.apache.jasper.runtime.HttpJspBase;   
    import org.apache.jasper.runtime.JspSourceDependent;   
    import org.apache.jasper.runtime.ResourceInjector;   
      
    public final class nn_005fbrowsedfscontent_jsp extends HttpJspBase   
      implements JspSourceDependent   
    {   
      private static final JspFactory _jspxFactory = JspFactory.getDefaultFactory();   
      private static Vector _jspx_dependants;   
      private ResourceInjector _jspx_resourceInjector;   
      
      //此处是将请求随机转发到一个DataNode节点上   
      public void redirectToRandomDataNode(NameNode nn, HttpServletResponse resp)   
        throws IOException   
      {   
        String nodeToRedirect;   
        int redirectPort;   
        FSNamesystem fsn = nn.getNamesystem();   
        String datanode = fsn.randomDataNode();   
      
        if (datanode != null) {   
          redirectPort = Integer.parseInt(datanode.substring(datanode.indexOf(58) + 1));   
          nodeToRedirect = datanode.substring(0, datanode.indexOf(58));   
        }   
        else {   
          nodeToRedirect = nn.getHttpAddress().getHostName();   
          redirectPort = nn.getHttpAddress().getPort();   
        }   
        // 此处是得到服务器的名称（hostname）   
        String fqdn = InetAddress.getByName(nodeToRedirect).getCanonicalHostName();   
        String redirectLocation = "http://" + fqdn + ":" + redirectPort + "/browseDirectory.jsp?namenodeInfoPort=" + nn.getHttpAddress().getPort() + "&dir=" + URLEncoder.encode("/", "UTF-8");   
      
        resp.sendRedirect(redirectLocation);   
      }   
      
      public Object getDependants()   
      {   
        return _jspx_dependants;   
      }   
      
      public void _jspService(HttpServletRequest request, HttpServletResponse response)   
        throws IOException, ServletException   
      {   
        PageContext pageContext = null;   
        HttpSession session = null;   
        ServletContext application = null;   
        ServletConfig config = null;   
        JspWriter out = null;   
        Object page = this;   
        JspWriter _jspx_out = null;   
        PageContext _jspx_page_context = null;   
        try  
        {   
          response.setContentType("text/html; charset=UTF-8");   
          pageContext = _jspxFactory.getPageContext(this, request, response, null, true, 8192, true);   
      
          _jspx_page_context = pageContext;   
          application = pageContext.getServletContext();   
          config = pageContext.getServletConfig();   
          session = pageContext.getSession();   
          out = pageContext.getOut();   
          _jspx_out = out;   
          this._jspx_resourceInjector = ((ResourceInjector)application.getAttribute("com.sun.appserv.jsp.resource.injector"));   
      
          out.write(10);   
          out.write("\n\n<html>\n\n<title></title>\n\n<body>\n");   
      
          NameNode nn = (NameNode)application.getAttribute("name.node");   
          redirectToRandomDataNode(nn, response);   
      
          out.write("\n<hr>\n\n<h2>Local logs</h2>\n<a href=\"/logs/\">Log</a> directory\n\n");   
      
          out.println(ServletUtil.htmlFooter());   
      
          out.write(10);   
        } catch (Throwable t) {   
          if (!(t instanceof SkipPageException)) {   
            out = _jspx_out;   
            if ((out != null) && (out.getBufferSize() != 0))   
              out.clearBuffer();   
            if (_jspx_page_context != null) _jspx_page_context.handlePageException(t);   
          }   
        } finally {   
          _jspxFactory.releasePageContext(_jspx_page_context);   
        }   
      }   
    }  

[java] view plaincopyprint?

    package org.apache.hadoop.hdfs.server.namenode;  
      
    import java.io.IOException;  
    import java.net.InetAddress;  
    import java.net.InetSocketAddress;  
    import java.net.URLEncoder;  
    import java.util.Vector;  
    import javax.servlet.ServletConfig;  
    import javax.servlet.ServletContext;  
    import javax.servlet.ServletException;  
    import javax.servlet.http.HttpServletRequest;  
    import javax.servlet.http.HttpServletResponse;  
    import javax.servlet.http.HttpSession;  
    import javax.servlet.jsp.JspFactory;  
    import javax.servlet.jsp.JspWriter;  
    import javax.servlet.jsp.PageContext;  
    import javax.servlet.jsp.SkipPageException;  
    import org.apache.hadoop.util.ServletUtil;  
    import org.apache.jasper.runtime.HttpJspBase;  
    import org.apache.jasper.runtime.JspSourceDependent;  
    import org.apache.jasper.runtime.ResourceInjector;  
      
    public final class nn_005fbrowsedfscontent_jsp extends HttpJspBase  
      implements JspSourceDependent  
    {  
      private static final JspFactory _jspxFactory = JspFactory.getDefaultFactory();  
      private static Vector _jspx_dependants;  
      private ResourceInjector _jspx_resourceInjector;  
      
      //此处是将请求随机转发到一个DataNode节点上  
      public void redirectToRandomDataNode(NameNode nn, HttpServletResponse resp)  
        throws IOException  
      {  
        String nodeToRedirect;  
        int redirectPort;  
        FSNamesystem fsn = nn.getNamesystem();  
        String datanode = fsn.randomDataNode();  
      
        if (datanode != null) {  
          redirectPort = Integer.parseInt(datanode.substring(datanode.indexOf(58) + 1));  
          nodeToRedirect = datanode.substring(0, datanode.indexOf(58));  
        }  
        else {  
          nodeToRedirect = nn.getHttpAddress().getHostName();  
          redirectPort = nn.getHttpAddress().getPort();  
        }  
        // 此处是得到服务器的名称（hostname）  
        String fqdn = InetAddress.getByName(nodeToRedirect).getCanonicalHostName();  
        String redirectLocation = "http://" + fqdn + ":" + redirectPort + "/browseDirectory.jsp?namenodeInfoPort=" + nn.getHttpAddress().getPort() + "&dir=" + URLEncoder.encode("/", "UTF-8");  
      
        resp.sendRedirect(redirectLocation);  
      }  
      
      public Object getDependants()  
      {  
        return _jspx_dependants;  
      }  
      
      public void _jspService(HttpServletRequest request, HttpServletResponse response)  
        throws IOException, ServletException  
      {  
        PageContext pageContext = null;  
        HttpSession session = null;  
        ServletContext application = null;  
        ServletConfig config = null;  
        JspWriter out = null;  
        Object page = this;  
        JspWriter _jspx_out = null;  
        PageContext _jspx_page_context = null;  
        try  
        {  
          response.setContentType("text/html; charset=UTF-8");  
          pageContext = _jspxFactory.getPageContext(this, request, response, null, true, 8192, true);  
      
          _jspx_page_context = pageContext;  
          application = pageContext.getServletContext();  
          config = pageContext.getServletConfig();  
          session = pageContext.getSession();  
          out = pageContext.getOut();  
          _jspx_out = out;  
          this._jspx_resourceInjector = ((ResourceInjector)application.getAttribute("com.sun.appserv.jsp.resource.injector"));  
      
          out.write(10);  
          out.write("\n\n<html>\n\n<title></title>\n\n<body>\n");  
      
          NameNode nn = (NameNode)application.getAttribute("name.node");  
          redirectToRandomDataNode(nn, response);  
      
          out.write("\n<hr>\n\n<h2>Local logs</h2>\n<a href=\"/logs/\">Log</a> directory\n\n");  
      
          out.println(ServletUtil.htmlFooter());  
      
          out.write(10);  
        } catch (Throwable t) {  
          if (!(t instanceof SkipPageException)) {  
            out = _jspx_out;  
            if ((out != null) && (out.getBufferSize() != 0))  
              out.clearBuffer();  
            if (_jspx_page_context != null) _jspx_page_context.handlePageException(t);  
          }  
        } finally {  
          _jspxFactory.releasePageContext(_jspx_page_context);  
        }  
      }  
    }  

从代码可以看出，当我们点击 Browse the filesystem时后台会将请求随机转发到一台DataNode节点，使用的是slaves文件中配置的服务器列表所反解的域名或主机名，而通过局域网IP未能反解出域名和主机名，所以用的是IP，这样就出问题了，解决办法有两个：视redirectToRandomDataNode方法内生成的URL而定，如果反转域名是主机名的话，你只需要修改本地HOSTS映射就可以了（推荐使用Windows Hosts Editor，软件地址： http://yymmiinngg.iteye.com/blog/360779）；如果反转出的域名是主机局域网IP的话，那就需要配置slaves和masters使用域名或外网IP。

该文章转载自http://blog.csdn.net/cnbird2008/article/details/8298259#