Error: Password file read access must be restricted: /etc/cassandra/jmxremote.password

在配置JMX远程访问的时候，设置jmxremote.password文件权限，修改该文件时添加写权限，chmod +w jmxremote.password ，放开角色信息那俩行的注释，保存，再使用chmod 0400 jmxremote.password

这样就是它正确的权限设置

jmxremote.password 在jdk/jre/lib/management/下，jmxremote.password.template复制，去掉.template后缀

转载请注明出处：http://blog.csdn.net/l1028386804/article/details/51547408

2016年5月的最后一天，今天我将和大家分享Java中如何使用JMX来监控Tomcat的各种状态。好了，不多说了，我们直接进入主题

一、激活Tomcat的JMX远程配置

要通过JMX远程监控Tomcat，首先需要激活Tomcat的JMX远程配置。

① 修改脚本

先修改Tomcat的启动脚本，windows下为bin/catalina.bat（linux下为catalina.sh），添加以下内容，8999是jmxremote使用的端口号，第二个false表示不需要鉴权：

set JMX_REMOTE_CONFIG=-Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=8999 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false
set CATALINA_OPTS=%CATALINA_OPTS% %JMX_REMOTE_CONFIG%

要注意以上语句的位置不能太后面，可以加在【if "%OS%" == "Windows_NT" setlocal】一句后的大段的注释后面。

参考官方说明：

http://tomcat.apache.org/tomcat-6.0-doc/monitoring.html#Enabling_JMX_Remote

http://tomcat.apache.org/tomcat-7.0-doc/monitoring.html#Enabling_JMX_Remote

http://tomcat.apache.org/tomcat-8.0-doc/monitoring.html#Enabling_JMX_Remote

http://tomcat.apache.org/tomcat-9.0-doc/monitoring.html#Enabling_JMX_Remote

② 鉴权

上面的配置是不需要鉴权的，如果需要鉴权则添加的内容为：

set JMX_REMOTE_CONFIG=-Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=8999 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=true -Dcom.sun.management.jmxremote.password.file=../conf/jmxremote.password -Dcom.sun.management.jmxremote.access.file=../conf/jmxremote.access
set CATALINA_OPTS=%CATALINA_OPTS% %JMX_REMOTE_CONFIG%

③ 复制并修改授权文件

$JAVA_HOME/jre/lib/management下有jmxremote.access和jmxremote.password的模板文件，将两个文件复制到$CATALINA_BASE/conf目录下
◆ 修改$CATALINA_BASE/conf/jmxremote.access 添加内容：
     monitorRole readonly
     controlRole readwrite
◆ 修改$CATALINA_BASE/conf/jmxremote.password 添加内容：
     monitorRole chenfeng
     controlRole chenfeng
注意： 如果进行了以上步骤导致Tomcat启动不了，那么很可能是密码文件的权限问题
需要修改jmxremote.password文件的访问权限，只有运行Tomcat的用户才能拥有访问权限 ：
      Windows的NTFS文件系统下，选中文件，点右键 -->“属性”-->“安全”--> 点“高级”--> 点“更改权限”--> 去掉“从父项继承....”--> 弹出窗口中选“删除”，这样就删除了所有访问权限。再选“添加”--> “高级”--> “立即查找”，选中你的用户（或用户组，如果选用户不行那就选用户组），例administrator，点“确定"，“确定"。来到权限项目窗口，勾选“完全控制”，点“确定”，OK了。
官方的提示：
      The password file should be read-only and only accessible by the operating system user Tomcat is running as.

④验证配置

重新启动Tomcat，在Windows命令行输入“netstat -a”查看配置的端口号是否已打开，如果打开，说明上面的配置成功了。

⑤ 使用jconsole测试JMX

运行$JAVA_HOME/bin目录下的jconsole.exe，打开J2SE监视和管理控制台，然后建立连接，如果是本地的Tomcat则直接选择然后点击连接，如果是远程的，则进入远程选项卡，填写地址、端口号、用户名、口令即可连接。。Mbean属性页中给出了相应的数据，Catalina中是tomcat的，java.lang是jvm的。对于加粗的黑体属性值，需双击一下才可看内容。

二、使用JMX监控Tomcat示例代码

String jmxURL = "service:jmx:rmi:///jndi/rmi://192.168.10.93:8999/jmxrmi";
JMXServiceURL serviceURL = new JMXServiceURL(jmxURL);

Map map = new HashMap();
// 用户名密码，在jmxremote.password文件中查看
String[] credentials = new String[] { "monitorRole", "tomcat" };
map.put("jmx.remote.credentials", credentials);
JMXConnector connector = JMXConnectorFactory.connect(serviceURL, map);
MBeanServerConnection mbsc = connector.getMBeanServerConnection();

// 端口最好是动态取得
ObjectName threadObjName = new ObjectName("Catalina:type=ThreadPool,name=http-8080");
MBeanInfo mbInfo = mbsc.getMBeanInfo(threadObjName);

// tomcat的线程数对应的属性值
String attrName = "currentThreadCount";
MBeanAttributeInfo[] mbAttributes = mbInfo.getAttributes();
System.out.println("currentThreadCount:" + mbsc.getAttribute(threadObjName, attrName));

三、完整的示例代码文件

import java.lang.management.MemoryUsage;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Formatter;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import javax.management.MBeanAttributeInfo;
import javax.management.MBeanInfo;
import javax.management.MBeanServerConnection;
import javax.management.ObjectInstance;
import javax.management.ObjectName;
import javax.management.openmbean.CompositeDataSupport;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXServiceURL;
/**
 * @author liuyazhuang
 * @date 2016-05-31
 */
public class JMXTest {

    /**
     * main方法
     * @param args
     */
    public static void main(String[] args) {
        try {

            String jmxURL = "service:jmx:rmi:///jndi/rmi://127.0.0.1:8999/jmxrmi";

            JMXServiceURL serviceURL = new JMXServiceURL(jmxURL);

            Map map = new HashMap();
            String[] credentials = new String[] { "monitorRole", "tomcat" };
            map.put("jmx.remote.credentials", credentials);
            JMXConnector connector = JMXConnectorFactory.connect(serviceURL,
                    map);
            MBeanServerConnection mbsc = connector.getMBeanServerConnection();

            // 端口最好是动态取得
            ObjectName threadObjName = new ObjectName(
                    "Catalina:type=ThreadPool,name=http-8080");
            MBeanInfo mbInfo = mbsc.getMBeanInfo(threadObjName);

            String attrName = "currentThreadCount";// tomcat的线程数对应的属性值
            MBeanAttributeInfo[] mbAttributes = mbInfo.getAttributes();
            System.out.println("currentThreadCount:"
                    + mbsc.getAttribute(threadObjName, attrName));

            // heap
            for (int j = 0; j < mbsc.getDomains().length; j++) {
                System.out.println("###########" + mbsc.getDomains()[j]);
            }
            Set MBeanset = mbsc.queryMBeans(null, null);
            System.out.println("MBeanset.size() : " + MBeanset.size());
            Iterator MBeansetIterator = MBeanset.iterator();
            while (MBeansetIterator.hasNext()) {
                ObjectInstance objectInstance = (ObjectInstance) MBeansetIterator
                        .next();
                ObjectName objectName = objectInstance.getObjectName();
                String canonicalName = objectName.getCanonicalName();
                System.out.println("canonicalName : " + canonicalName);
                if (canonicalName
                        .equals("Catalina:host=localhost,type=Cluster")) {
                    // Get details of cluster MBeans
                    System.out.println("Cluster MBeans Details:");
                    System.out
                            .println("=========================================");
                    // getMBeansDetails(canonicalName);
                    String canonicalKeyPropList = objectName
                            .getCanonicalKeyPropertyListString();
                }
            }
            // ------------------------- system ----------------------
            ObjectName runtimeObjName = new ObjectName("java.lang:type=Runtime");
            System.out.println("厂商:"
                    + (String) mbsc.getAttribute(runtimeObjName, "VmVendor"));
            System.out.println("程序:"
                    + (String) mbsc.getAttribute(runtimeObjName, "VmName"));
            System.out.println("版本:"
                    + (String) mbsc.getAttribute(runtimeObjName, "VmVersion"));
            Date starttime = new Date((Long) mbsc.getAttribute(runtimeObjName,
                    "StartTime"));
            SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            System.out.println("启动时间:" + df.format(starttime));

            Long timespan = (Long) mbsc.getAttribute(runtimeObjName, "Uptime");
            System.out.println("连续工作时间:" + JMXTest.formatTimeSpan(timespan));
            // ------------------------ JVM -------------------------
            // 堆使用率
            ObjectName heapObjName = new ObjectName("java.lang:type=Memory");
            MemoryUsage heapMemoryUsage = MemoryUsage
                    .from((CompositeDataSupport) mbsc.getAttribute(heapObjName,
                            "HeapMemoryUsage"));
            long maxMemory = heapMemoryUsage.getMax();// 堆最大
            long commitMemory = heapMemoryUsage.getCommitted();// 堆当前分配
            long usedMemory = heapMemoryUsage.getUsed();
            System.out.println("heap:" + (double) usedMemory * 100
                    / commitMemory + "%");// 堆使用率

            MemoryUsage nonheapMemoryUsage = MemoryUsage
                    .from((CompositeDataSupport) mbsc.getAttribute(heapObjName,
                            "NonHeapMemoryUsage"));
            long noncommitMemory = nonheapMemoryUsage.getCommitted();
            long nonusedMemory = heapMemoryUsage.getUsed();
            System.out.println("nonheap:" + (double) nonusedMemory * 100
                    / noncommitMemory + "%");

            ObjectName permObjName = new ObjectName(
                    "java.lang:type=MemoryPool,name=Perm Gen");
            MemoryUsage permGenUsage = MemoryUsage
                    .from((CompositeDataSupport) mbsc.getAttribute(permObjName,
                            "Usage"));
            long committed = permGenUsage.getCommitted();// 持久堆大小
            long used = heapMemoryUsage.getUsed();//
            System.out.println("perm gen:" + (double) used * 100 / committed
                    + "%");// 持久堆使用率

            // -------------------- Session ---------------
            ObjectName managerObjName = new ObjectName(
                    "Catalina:type=Manager,*");
            Set<ObjectName> s = mbsc.queryNames(managerObjName, null);
            for (ObjectName obj : s) {
                System.out.println("应用名:" + obj.getKeyProperty("path"));
                ObjectName objname = new ObjectName(obj.getCanonicalName());
                System.out.println("最大会话数:"
                        + mbsc.getAttribute(objname, "maxActiveSessions"));
                System.out.println("会话数:"
                        + mbsc.getAttribute(objname, "activeSessions"));
                System.out.println("活动会话数:"
                        + mbsc.getAttribute(objname, "sessionCounter"));
            }

            // ----------------- Thread Pool ----------------
            ObjectName threadpoolObjName = new ObjectName(
                    "Catalina:type=ThreadPool,*");
            Set<ObjectName> s2 = mbsc.queryNames(threadpoolObjName, null);
            for (ObjectName obj : s2) {
                System.out.println("端口名:" + obj.getKeyProperty("name"));
                ObjectName objname = new ObjectName(obj.getCanonicalName());
                System.out.println("最大线程数:"
                        + mbsc.getAttribute(objname, "maxThreads"));
                System.out.println("当前线程数:"
                        + mbsc.getAttribute(objname, "currentThreadCount"));
                System.out.println("繁忙线程数:"
                        + mbsc.getAttribute(objname, "currentThreadsBusy"));
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static String formatTimeSpan(long span) {
        long minseconds = span % 1000;

        span = span / 1000;
        long seconds = span % 60;

        span = span / 60;
        long mins = span % 60;

        span = span / 60;
        long hours = span % 24;

        span = span / 24;
        long days = span;
        return (new Formatter()).format("%1$d天 %2$02d:%3$02d:%4$02d.%5$03d",
                days, hours, mins, seconds, minseconds).toString();
    }
}