使用jattach 在host 节点查看容器jvm信息

jattach是基于hostspot attach api 指南编写的轻量all in one(jmap,jstack,jcmd,jinfo) 的工具
包含了以下命令

• load 家在agent library
• properties 加载系统属性
• agentproperties 打印agent 属性信息
• datadump 显示heap 以及thread 统计信息
• threaddump dump 所有栈的追踪信息（类似jstack）
• inspectheap heap 直方图（类似jmap -histo）
• setflag 修改托管vm flag 信息
• printflag 打印vm flag 信息
• jcmd 执行jcmd 命令

安装

我们只需要jre，不需要jdk，同时支持容器的jvm 信息查看，官方提供了编译好的二进制文件，同时对于容器也支持了包

简单使用

• 启动一个tomcat 容器

 

docker run -d tomcat

• host 查看容器pid

ps -ef |grep tomcat

 

• 查看jvm 信息
  host 机器

 

jattach 22408 jcmd Thread.print

Connected to remote JVM

Response code = 0

2019-12-13 01:51:23

Full thread dump OpenJDK 64-Bit Server VM (25.232-b09 mixed mode):

​

"Attach Listener" #46 daemon prio=9 os_prio=0 tid=0x00007f49e0001000 nid=0x37 waiting on condition [0x0000000000000000]

   java.lang.Thread.State: RUNNABLE

​

"ajp-nio-8009-AsyncTimeout" #44 daemon prio=5 os_prio=0 tid=0x00007f4a106fd800 nid=0x36 waiting on condition [0x00007f49c913f000]

   java.lang.Thread.State: TIMED_WAITING (sleeping)

 at java.lang.Thread.sleep(Native Method)

 at org.apache.coyote.AbstractProtocol$AsyncTimeout.run(AbstractProtocol.java:1162)

 at java.lang.Thread.run(Thread.java:748)

​

"ajp-nio-8009-Acceptor-0" #43 daemon prio=5 os_prio=0 tid=0x00007f4a106fb800 nid=0x35 runnable [0x00007f49c9240000]

   java.lang.Thread.State: RUNNABLE

 at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method)

 at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:422)

 at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:250)

 - locked <0x00000000ee300f50> (a java.lang.Object)

 at org.apache.tomcat.util.net.NioEndpoint$Acceptor.run(NioEndpoint.java:482)

 at java.lang.Thread.run(Thread.java:748)

​

"ajp-nio-8009-ClientPoller-1" #42 daemon prio=5 os_prio=0 tid=0x00007f4a106fa000 nid=0x34 runnable [0x00007f49c9341000]

   java.lang.Thread.State: RUNNABLE

 at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method)

 at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269)

 at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93)

 at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86)

 - locked <0x00000000ec6cfbf0> (a sun.nio.ch.Util$3)

 - locked <0x00000000ec6cfbe0> (a java.util.Collections$UnmodifiableSet)

 - locked <0x00000000ec6cfac8> (a sun.nio.ch.EPollSelectorImpl)

 at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)

 at org.apache.tomcat.util.net.NioEndpoint$Poller.run(NioEndpoint.java:825)

 at java.lang.Thread.run(Thread.java:748)

.....

说明

jattach 是一个很不错的工具，我们可以用来方便的分析记基于容器的jvm 应用性能，简单方便

参考资料

https://github.com/apangin/jattach