Linux系统及应用问题分析排查工具

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摘要： Linux服务器上经常遇到一些系统和应用上的问题，如何分析排查，需要利器，下面总结列表了一些常用工具、trace tool；最后也列举了最近hadoop社区在开发发展的分布式系统的trace tool。 概览： 引用linux-performance-analysis-and-tools中图片，

Linux服务器上经常遇到一些系统和应用上的问题，如何分析排查，需要利器，下面总结列表了一些常用工具、trace tool；最后也列举了最近hadoop社区在开发发展的分布式系统的trace tool。

概览：

引用 中图片，说明这些tool试用层次位置

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OS系统命令

系统信息（RHEL/Fedora）

• uname -a 或 cat /proc/version #print system information

• Linux hadoopst2.cm6 2.6.18-164.el5 #1 SMP Tue Aug 18 15:51:48 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

• uptime

• 15:42:46 up 674 days, 6 min, 35 users, load average: 1.30, 5.97, 11.53

• cat /etc/redhat-release

• Red Hat Enterprise Linux Server release 5.4 (Tikanga)

• lsb_release

• LSB Version:  :core-3.1-amd64:core-3.1-ia32:core-3.1-noarch:graphics-3.1-amd64:graphics-3.1-ia32:graphics-3.1-noarch

• cat /proc/cpuinfo
• cat /proc/meminfo
• lspci - list all PCI devices
• lsusb - list USB devices
• last, lastb - show listing of last logged in users
• lsmod — show the status of modules in the Linux Kernel
• modprobe - add and remove modules from the Linux Kernel

常用命令/工具

• ps

• To print a process tree: ps -ejH / ps axjf
• To get info about threads: ps -eLf / ps axms

• ulimit -a
• lsof - list open files, UNIX一切皆文件

• lsof -p PID

• rpm/yum

• rpm -qf FILE #文件所属rpm包
• rpm -ql RPM #rpm包含文件
• /var/log/yum.log #yum 更新包日志

• /etc/XXX #系统级程序配置目录， 如

• /etc/yum.repos.d/ yum源配置

• /var/log/XXX #日志目录， 如

• /var/log/cron #crontab日志，可以查看调度执行情况

• ntpd - Network Time Protocol (NTP) daemon，同步集群中机器时间
• squid - proxy caching server，集群WebUI的代理

系统监控

• mpstat - Report processors related statistics. 注意%sys %iowait值
• vmstat - Report virtual memory statistics
• iostat - Report Central Processing Unit (CPU) statistics and input/output statistics for devices and partitions.
• netstat - Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships

• netstat -atpn | grep PID

• - a scalable distributed monitoring system for high-performance computing systems such as clusters and Grids.
• sar/tsar - Collect, report, or save system activity information; tsar是淘宝自己改进的版本

• 定时采样（每分钟），可查历史记录（默认5分钟），可弥补ganglia显示更详细信息

• iftop - the "top" bandwidth consumers shown.  ​
• Portable file system cache diagnostics and control

网络相关

• telnet/nc IP PORT - 确认目标端口是否可访问，只ping通不一定端口可访问，可能防火墙等禁止
• ifconfig/ifup/ifdown - configure a network interface
• traceroute - print the route packets trace to network host
• nslookup - query Internet name servers interactively
• tcpdump - dump traffic on a network， 类似开源工具 ​​
• lynx - a general purpose distributed information browser for the World Wide Web
• - allows cooperating applications to pass ownership of TCP connection endpoints from one Linux host to another one.

程序/进程相关

静态信息

• ldconfig - configure dynamic linker run time bindings

• ldconfig -p | grep SO 查看so是否在link cache中

• ldd - print shared library dependencies， 查看exe或so依赖的so
• nm - list symbols from object files，可grep查找是否存在相关的symbol，是否Undefined.
• readelf - Displays information about ELF files. 可现实elf相关信息，如32/64位，适用的OS，处理器

动态信息

• gdb
• cat /proc/$PID/[cmdline|environ|limits|status|...] - 进程相关信息
• pstack - print a stack trace of a running process
• pmap - report memory map of a process

java相关

• ​
  
• jinfo - print java process information, 如classpath，java.libary.path（jni so目录）
• jstack - print a stack trace of a running java process，可查看死锁情况
• jmap - report memory map of a java process

• jmap -histo:live 可触发full gc
• jmap -dump:live,file=$FILE 可dump heap内存，用于jhat等工具debug分析object在heap的占用情况

• jhat - Heap Dump Browser - Starts a web server on a heap dump file (eg, produced by jmap -dump), allowing the heap to be browsed.

• 起http服务，浏览器访问查看
• -J-mxXXXm ，分析大文件时需要加大heap大小
• 若有对象数据超大或内存占用过多，极有可能memory leak

• - eclipse plugin，Java heap analyzer

• 可视化工具，但受到机器内存的限制，无法分析太大的heap dump file

• jdb - 可起服务做server，eclipse等工具远程连接调试
• jstat - Java Virtual Machine Statistics Monitoring Tool
• jstatd - Virtual Machine jstat Daemon，可配合jvisualvm
• jvisualvm - Java Virtual Machine Monitoring, Troubleshooting, and Profiling Tool；可远程连接jstatd/jmx, 可视化展示工具：演示
• ​ - In a top-like manner, displays JVM internal metrics (e.g. memory information) of running java processes.

1. ​

• HPROF - Heap Profiler： java -agentlib:hprof

Trace/Debug/Profiling工具

通用工具

• 写log，但系统在线或无法源码时
• strace - trace system calls and signals

• ​
• 示例：可跟踪系统调用时间，如机器cpu:%sys高的问题

% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
 67.90 3966.320849         496   7992161   3050250 futex
 25.80 1507.326693      127093     11860           epoll_wait
....................

• generate traces of the i/o traffic on block devices
• ​
  
• a performance analysis tool, sampling and call-graph profiling
• ​​ - an instrumentation framework for building dynamic analysis tools. automatically a simple command line interface and scripting language for writing instrumentation for a live running kernel plus user-space applications for complex tasks that may require live analysis, programmable on-line response, and whole-system symbolic access.

• Linux版DTrace（SUN在Solaris上开发的）
• 功能强大，kernel， user-space app，cross language（java perl python ruby），build-in markers（pg mysql）
• can write and reuse simple scripts to deeply examine the activities of a live system
• Data can be extracted, filtered, and summarized quickly and safely, to enable diagnoses of complex performance or functional problems
• 丰富的 "tapset" script library

java trace工具

• - dynamic tracing tool for the Java platform. ​​

• 基于动态字节码修改技术(Hotswap)来实现运行时java程序的跟踪和替换, ​​ ​
• ​
•  - simplifies tracing and testing of Java programs. Can modify a running application without needing to stop and restart it.

• define rules specifying the side effects you want to inject 而 BTrace类java语法

Distributed Tracing Tools

 

• , a Large-Scale Distributed Systems Tracing Infrastructure
• , a network diagnostic tool designed to provide users and network operators with better  a tracing framework intended for use with distributed systems written in java