[alibaba/arthas]两个容器，同一个namespace下，arthask可以attach吗？目前测试不行

• Arthas 版本: 3.5.6
• 操作系统版本: ubuntu20.04
• 目标进程的JVM版本: 1.8
• 执行arthas-boot的版本: 3.5.6

1. 主容器启动业务进程
2. 新启动容器加入注入器namespace
3. 在新启动容器中 java -jar arthas-boot.jar PID

可以正常attach

attach失败

pp@sktest-vm-demo-79f784bd99-jxvv5:/$ java -jar /opt/arthas/arthas-boot.jar 7
[INFO] arthas-boot version: 3.5.6
[INFO] arthas home: /opt/arthas
[INFO] Try to attach process 7
[ERROR] Start arthas failed, exception stack trace: 
com.sun.tools.attach.AttachNotSupportedException: Unable to open socket file: target process not responding or HotSpot VM not loaded
        at sun.tools.attach.LinuxVirtualMachine.<init>(LinuxVirtualMachine.java:106)
        at sun.tools.attach.LinuxAttachProvider.attachVirtualMachine(LinuxAttachProvider.java:63)
        at com.sun.tools.attach.VirtualMachine.attach(VirtualMachine.java:208)
        at com.taobao.arthas.core.Arthas.attachAgent(Arthas.java:100)
        at com.taobao.arthas.core.Arthas.<init>(Arthas.java:27)
        at com.taobao.arthas.core.Arthas.main(Arthas.java:151)
[INFO] Attach process 7 success.
[INFO] arthas-client connect 127.0.0.1 3658
Connect to telnet server error: 127.0.0.1 3658
java.net.ConnectException: Connection refused (Connection refused)
        at java.net.PlainSocketImpl.socketConnect(Native Method)
        at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
        at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
        at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
        at java.net.Socket.connect(Socket.java:607)
        at org.apache.commons.net.SocketClient.connect(SocketClient.java:188)
        at org.apache.commons.net.SocketClient.connect(SocketClient.java:209)
        at com.taobao.arthas.client.TelnetConsole.process(TelnetConsole.java:306)
        at com.taobao.arthas.client.TelnetConsole.main(TelnetConsole.java:166)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at com.taobao.arthas.boot.Bootstrap.main(Bootstrap.java:615)
Usage: arthas-client [--help] [-c <value>] [-f <value>] [-w <value>] [-t
       <value>] [-h <value>] [target-ip] [port]