JVM可以在服务运行时实时修改生效的监控参数

妖狐艹你老母 2023-06-25 08:22 34阅读 0赞

环境：java version "1.8.0\_131"

查看某个进程所有参数配置

\[root@izbp1c /\]\# jps  
15154 -- process information unavailable  
24979 jar   -- 目标进程  
17544 Jps  
16573 Logstash  
\[root@izbp1c /\]\# java -XX:+PrintFlagsFinal 24979    **-->  查看jvm所有当前服务使用的配置参数**

所有参数中只有末尾以 **\{manageable\}** 标识的参数才是可以实时修改的参数，具体参数列表如下：

<table style="width:692px;">  可动态配置的JVM参数  
 <tbody> 
  <tr> 
   <td>参数</td> 
   <td style="width:109px;">参数类型</td> 
   <td style="width:97px;">默认值</td> 
   <td style="width:242px;">可修改标志</td> 
  </tr> 
  <tr> 
   <td>CMSAbortablePrecleanWaitMillis</td> 
   <td style="width:109px;">intx</td> 
   <td style="width:97px;">= 100</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>CMSTriggerInterval</td> 
   <td style="width:109px;">intx</td> 
   <td style="width:97px;">= -1&nbsp;</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>CMSWaitDuration</td> 
   <td style="width:109px;">intx</td> 
   <td style="width:97px;">= 2000</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>HeapDumpAfterFullGC</td> 
   <td style="width:109px;">bool</td> 
   <td style="width:97px;">= false</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>HeapDumpBeforeFullGC</td> 
   <td style="width:109px;">bool</td> 
   <td style="width:97px;">= false</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>HeapDumpOnOutOfMemoryError</td> 
   <td style="width:109px;">bool</td> 
   <td style="width:97px;">= false</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>HeapDumpPath</td> 
   <td style="width:109px;">ccstr</td> 
   <td style="width:97px;">=&nbsp;</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>MaxHeapFreeRatio</td> 
   <td style="width:109px;">uintx</td> 
   <td style="width:97px;">= 70</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>MinHeapFreeRatio</td> 
   <td style="width:109px;">uintx</td> 
   <td style="width:97px;">= 40</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>PrintClassHistogram</td> 
   <td style="width:109px;">bool</td> 
   <td style="width:97px;">= false&nbsp;</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>PrintClassHistogramAfterFullGC</td> 
   <td style="width:109px;">bool</td> 
   <td style="width:97px;">= false&nbsp;</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>PrintClassHistogramBeforeFullGC</td> 
   <td style="width:109px;">bool</td> 
   <td style="width:97px;">= false&nbsp;</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>PrintConcurrentLocks</td> 
   <td style="width:109px;">bool</td> 
   <td style="width:97px;">= false&nbsp;</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>PrintGC</td> 
   <td style="width:109px;">bool</td> 
   <td style="width:97px;">= false&nbsp;</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>PrintGCDateStamps</td> 
   <td style="width:109px;">bool</td> 
   <td style="width:97px;">= false&nbsp;</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>PrintGCDetails</td> 
   <td style="width:109px;">bool</td> 
   <td style="width:97px;">= false&nbsp;</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>PrintGCID</td> 
   <td style="width:109px;">bool</td> 
   <td style="width:97px;">= false&nbsp;</td> 
   <td style="width:242px;">{manageable}</td> 
  </tr> 
  <tr> 
   <td>PrintGCTimeStamps</td> 
   <td style="width:109px;">bool</td> 
   <td style="width:97px;">= false&nbsp;</td> 
   <td style="width:242px;"> <p>{manageable}</p> </td> 
  </tr> 
 </tbody> 
</table>

修改方法：jinfo -flag  参数名=要设置参数值 $\{ service PID \}

如：

jinfo  -flag  +HeapDumpAfterFullGC  \{ java-pid \}    --- 开启HeapDumpAfterFullGC   
jinfo  -flag  -HeapDumpAfterFullGC  \{ java-pid \}     --- 关闭HeapDumpAfterFullGC

jinfo -flag +HeapDumpBeforeFullGC  \{ java--pid \}   --- 开启  
jinfo -flag -HeapDumpBeforeFullGC  \{ java--pid \}   --- 关闭

jinfo -flag HeapDumpPath=../heap.hprof  \{ java--pid \}  ---指定dump快照路径