background

The project is running , Whether it is running in the expected way , Memory and CPU The occupancy of , Thread count and so on , How to monitor and view .

At this time, ordinary people will look for operation and maintenance , Now there are open source - arthas.

Arthas Data presentation

Arthas explain

Arthas yes Alibaba Open source Java Diagnostic tools , Loved by developers .

When you encounter the following similar problems and are at a loss ,Arthas Can help you solve ：

    Where does this class come from jar Package loaded ？ Why do you report all kinds of related Exception？
    Why didn't I change the code to ？ I didn't commit？ The branch is wrong ？
    I can't get online when I have a problem debug, Can't we just add logs and redistribute them ？
    There is a problem with the data processing of a user online , But online also can't debug, It can't be reproduced offline ！
    Is there a global perspective to see the health of the system ？
    Is there any way to monitor JVM The real-time running state of ？
    How to quickly locate the hot spot of application , Generate flame chart ？
    How to directly from JVM Find an instance of a class in ？

Arthas Support JDK 6+, Support Linux/Mac/Windows, Use command line interaction mode , At the same time, it provides rich Tab Automatic completion function , Further facilitate problem location and diagnosis .

Project address ：https://gitee.com/arthas/arthas

1、 Download the package and run it

wget https://arthas.aliyun.com/arthas-boot.jar

Start command ：

java -jar arthas-boot.jar

arthas-boot yes Arthas Start up procedure for , When it starts up , Will list all Java process , The user can select the target process to be diagnosed .

Select the first process , Input 1 , Again Enter/ enter ：

If you want to select the second process , Input 2, Again Enter/ enter ：

... ...

And so on （ Monitor only one program at a time , Don't be greedy ）

Attach After success , prints Arthas LOGO. Input help You can get more help information .

2、 Kanban Dashboard

dashboard Command to view the real-time data panel of the current system .

Input Q perhaps Ctrl+C You can quit dashboard command .

3、Thread

thread 1 The command prints the thread ID 1 The stack .

Arthas Support piping , It can be used thread 1 | grep 'main(' Find the main class.

You can see main class yes demo.MathGame：

$ thread 1 | grep 'main('
    at demo.MathGame.main(MathGame.java:17)

4、Sc

Can pass sc Command to find JVM Class loaded in ：

sc -d *MathGame

5、Jad

Can pass jad Command to decompile the code ：

jad demo.MathGame

6、Watch

adopt watch Command can view the parameters of the function / Return value / Abnormal information .

watch demo.MathGame primeFactors returnObj

Input Q perhaps Ctrl+C sign out watch command .

7、Vmtool

adopt vmtool command , You can search memory objects .

vmtool --action getInstances --className java.lang.String --limit 10

bash
$ vmtool --action getInstances --className java.lang.String --limit 10
@String[][
    @String[com/taobao/arthas/core/shell/session/Session],
    @String[com.taobao.arthas.core.shell.session.Session],
    @String[com/taobao/arthas/core/shell/session/Session],
    @String[com/taobao/arthas/core/shell/session/Session],
    @String[com/taobao/arthas/core/shell/session/Session.class],
    @String[com/taobao/arthas/core/shell/session/Session.class],
    @String[com/taobao/arthas/core/shell/session/Session.class],
    @String[com/],
    @String[java/util/concurrent/ConcurrentHashMap$ValueIterator],
    @String[java/util/concurrent/locks/LockSupport],
]

8、Exit/Stop

sign out Arthas

use exit perhaps quit Command can exit Arthas.

sign out Arthas after , You can also use... Again java -jar arthas-boot.jar To connect .
To withdraw completely Arthas

exit/quit The command simply exits the current session,arthas server Still running in the target process .

Want to quit completely Arthas, It can be executed stop command .

Basically master the above common commands , You can kill a lot of development . Promotion and raise are just around the corner ！

Most of the above content comes from official documents , If you are interested, you can take a look at it yourself .

Reference resources ：Arthas User documentation — Arthas 3.6.2 file