/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.mapred;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Collections;
import java.util.HashMap;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.hadoop.mapreduce.TaskType;
import org.apache.hadoop.mapred.JobHistory.JobInfo;
import org.apache.hadoop.util.StringUtils;
/**
* Servlet for displaying fair scheduler information, installed at [job tracker
* URL]/scheduler when the {@link FairScheduler} is in use.
*
* The main features are viewing each job's task count and fair share, ability
* to change job priorities and pools from the UI, and ability to switch the
* scheduler to FIFO mode without restarting the JobTracker if this is required
* for any reason.
*
* There is also an "advanced" view for debugging that can be turned on by going
* to [job tracker URL]/scheduler?advanced.
*/
public class CapacitySchedulerServlet extends HttpServlet {
private static final long serialVersionUID = 9104070533067306659L;
private transient CapacityTaskScheduler scheduler;
private transient JobTracker jobTracker;
@Override
public void init() throws ServletException {
super.init();
ServletContext servletContext = this.getServletContext();
this.scheduler = (CapacityTaskScheduler) servletContext
.getAttribute("scheduler");
this.jobTracker = (JobTracker) scheduler.taskTrackerManager;
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
doGet(req, resp); // Same handler for both GET and POST
}
@Override
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// Print out the normal response
response.setContentType("text/html");
// Because the client may read arbitrarily slow, and we hold locks while
// the servlet output, we want to write to our own buffer which we know
// won't block.
ByteArrayOutputStream baos = new ByteArrayOutputStream();
PrintWriter out = new PrintWriter(baos);
String hostname = StringUtils.simpleHostname(jobTracker
.getJobTrackerMachine());
out.print("<html><head>");
out.printf("<title>%s Job Scheduler Admininstration</title>\n", hostname);
out.print("<link rel=\"stylesheet\" type=\"text/css\" "
+ "href=\"/static/hadoop.css\">\n");
out.print("<script type=\"text/javascript\" "
+ "src=\"/static/sorttable.js\"></script> \n");
out.print("</head><body>\n");
out.printf("<h1><a href=\"/jobtracker.jsp\">%s</a> "
+ "Job Scheduler Administration</h1>\n", hostname);
showQueues(out);
out.print("</body></html>\n");
out.close();
// Flush our buffer to the real servlet output
OutputStream servletOut = response.getOutputStream();
baos.writeTo(servletOut);
servletOut.close();
}
/**
* Print a view of pools to the given output writer.
*/
private void showQueues(PrintWriter out)
throws IOException {
synchronized(scheduler) {
out.print("<h2>Queues</h2>\n");
out.print("<table border=\"2\" cellpadding=\"5\" " +
" cellspacing=\"2\" class=\"sortable\"> \n");
out.print("<tr><th>Queue</th>" +
"<th>Running Jobs</th>" +
"<th>Pending Jobs</th>" +
"<th>Capacity Percentage</th>" +
"<th>Map Task Capacity</th>" +
"<th>Map Task Used Capacity</th>" +
"<th>Running Maps</th>" +
"<th>Reduce Task Capacity</th>" +
"<th>Reduce Task Used Capacity</th>" +
"<th>Running Reduces </tr>\n");
for (CapacitySchedulerQueue queue : scheduler.getQueueInfoMap().values()) {
String queueName = queue.getQueueName();
out.print("<tr>\n");
out.printf(
"<td><a href=\"jobqueue_details.jsp?queueName=%s\">%s</a></td>\n",
queueName, queueName);
out.printf("<td>%s</td>\n",
(queue.getNumRunningJobs() + queue.getNumInitializingJobs()));
out.printf("<td>%s</td>\n", queue.getNumWaitingJobs());
out.printf("<td>%.1f%%</td>\n", queue.getCapacityPercent());
int mapCapacity = queue.getCapacity(TaskType.MAP);
int mapSlotsOccupied = queue.getNumSlotsOccupied(TaskType.MAP);
int reduceSlotsOccupied = queue.getNumSlotsOccupied(TaskType.REDUCE);
float occupiedSlotsAsPercent =
mapCapacity != 0 ? ((float) mapSlotsOccupied * 100 / mapCapacity)
: 0;
out.printf("<td>%s</td>\n", mapCapacity);
out.printf("<td>%s (%.1f%% of Capacity)</td>\n", mapSlotsOccupied,
occupiedSlotsAsPercent);
out.printf("<td>%s</td>\n", queue.getNumRunningTasks(TaskType.MAP));
int reduceCapacity = queue.getCapacity(TaskType.REDUCE);
float redOccupiedSlotsAsPercent =
(reduceCapacity != 0 ? ((float)reduceSlotsOccupied*100 / mapCapacity)
: 0);
out.printf("<td>%s</td>\n", reduceCapacity);
out.printf("<td>%s (%.1f%% of Capacity)</td>\n", reduceSlotsOccupied,
redOccupiedSlotsAsPercent);
out.printf("<td>%s</td>\n", queue.getNumRunningTasks(TaskType.REDUCE));
}
out.print("</table>\n");
}
}
}