Package org.apache.hadoop.http

Class IsActiveServlet

java.lang.Object
javax.servlet.GenericServlet
javax.servlet.http.HttpServlet
org.apache.hadoop.http.IsActiveServlet
All Implemented Interfaces:
Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig
public abstract class IsActiveServlet extends javax.servlet.http.HttpServlet
Used by Load Balancers to detect the active NameNode/ResourceManager/Router.
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    PATH_SPEC
     
    static final String
    RESPONSE_ACTIVE
     
    static final String
    RESPONSE_NOT_ACTIVE
     
    static final String
    SERVLET_NAME
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    IsActiveServlet()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    doGet(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp)
    Check whether this instance is the Active one.
    protected abstract boolean
    isActive()
     

    Methods inherited from class javax.servlet.http.HttpServlet

    doDelete, doHead, doOptions, doPost, doPut, doTrace, getLastModified, service, service

    Methods inherited from class javax.servlet.GenericServlet

    destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, init, log, log

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

  • Constructor Details

    • IsActiveServlet

      public IsActiveServlet()

  • Method Details

    • doGet

      public void doGet(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp) throws IOException
      Check whether this instance is the Active one.
      Overrides:
      doGet in class javax.servlet.http.HttpServlet
      Parameters:
      req - HTTP request
      resp - HTTP response to write to
      Throws:
      IOException

    • isActive

      protected abstract boolean isActive()
      Returns:
      true if this instance is in Active HA state.