server/src/com/cloud/ha/HighAvailabilityManagerExtImpl.java

/**
 * *  Copyright (C) 2011 Citrix Systems, Inc.  All rights reserved
*
 *
 * This software is licensed under the GNU General Public License v3 or later.
 *
 * It is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

package com.cloud.ha;

import java.util.Date;
import java.util.Map;
import java.util.concurrent.TimeUnit;

import javax.ejb.Local;
import javax.naming.ConfigurationException;

import com.cloud.alert.AlertManager;
import com.cloud.configuration.dao.ConfigurationDao;
import com.cloud.server.ManagementServer;
import com.cloud.usage.dao.UsageJobDao;
import com.cloud.utils.component.ComponentLocator;
import com.cloud.utils.component.Inject;
import com.cloud.utils.db.Transaction;

@Local(value={HighAvailabilityManager.class})
public class HighAvailabilityManagerExtImpl extends HighAvailabilityManagerImpl {
	
    @Inject
	UsageJobDao _usageJobDao;
    ConfigurationDao configDao;
    
	@Override
	public boolean configure(final String name, final Map<String, Object> xmlParams) throws ConfigurationException {
		super.configure(name, xmlParams);

		ComponentLocator locator = ComponentLocator.getLocator(ManagementServer.Name);
        
        configDao = locator.getDao(ConfigurationDao.class);
        if (configDao == null) 
        {
        	s_logger.warn("Unable to get a configuration dao to check config value for enableUsageServer");
        	return false;
        }

        return true;
	}

	@Override
    public boolean start() 
	{
		super.start();
		
	        
        boolean enableUsage = new Boolean(configDao.getValue("enable.usage.server"));
        
        //By default, usage is enabled for production
        //Devs might override this value to disable usage in their setup
        if(enableUsage)
        {
        	_executor.scheduleAtFixedRate(new UsageServerMonitorTask(), 60*60, 10*60, TimeUnit.SECONDS); // schedule starting in one hour to execute every 10 minutes
        }
        
        return true;
    }
	
	protected class UsageServerMonitorTask implements Runnable {
        @Override
        public void run() {
            if (s_logger.isInfoEnabled()) {
                s_logger.info("checking health of usage server");
            }

            try {
                boolean isRunning = false;
                Transaction txn = Transaction.open(Transaction.USAGE_DB);
                try {
                    Date lastHeartbeat = _usageJobDao.getLastHeartbeat();
                    if (lastHeartbeat != null) {
                        long sinceLastHeartbeat = System.currentTimeMillis() - lastHeartbeat.getTime();
                        if (sinceLastHeartbeat <= (10 * 60 * 1000)) {
                            // if it's been less than 10 minutes since the last heartbeat, then it appears to be running, otherwise send an alert
                            isRunning = true;
                        }
                    }
                    if (s_logger.isDebugEnabled()) {
                        s_logger.debug("usage server running? " + isRunning + ", heartbeat: " + lastHeartbeat);
                    }
                } finally {
                    txn.close();

                    // switch back to VMOPS db
                    Transaction swap = Transaction.open(Transaction.CLOUD_DB);
                    swap.close();
                }

                if (!isRunning) {
                    _alertMgr.sendAlert(AlertManager.ALERT_TYPE_USAGE_SERVER, 0, new Long(0), "No usage server process running", "No usage server process has been detected, some attention is required");
                } else {
                    _alertMgr.clearAlert(AlertManager.ALERT_TYPE_USAGE_SERVER, 0, 0);
                }
            } catch (Exception ex) {
                s_logger.warn("Error while monitoring usage job", ex);
            }
        }
    }
}