套用一个 shell 脚本，可助你排查 Linux 系统 CPU 100% 异常问题

#!/bin/bash# @Function# Find out the highest cpu consumed threads of java, and print the stack of these threads.## @Usage#   $ ./show-busy-java-threads.sh## @author Jerry Lee
readonly PROG=`basename $0`readonly -a COMMAND_LINE=("$0" "$@")
usage() {    cat <<EOFUsage: ${PROG} [OPTION]...Find out the highest cpu consumed threads of java, and print the stack of these threads.Example: ${PROG} -c 10
Options:    -p, --pid       find out the highest cpu consumed threads from the specifed java process,                    default from all java process.    -c, --count     set the thread count to show, default is 5    -h, --help      display this help and exitEOFexit $1}
readonly ARGS=`getopt -n "$PROG" -a -o c:p:h -l count:,pid:,help -- "$@"`[ $? -ne 0 ] && usage 1eval set -- "${ARGS}"
while true; docase "$1" in    -c|--count)        count="$2"shift 2        ;;    -p|--pid)        pid="$2"shift 2        ;;    -h|--help)        usage        ;;    --)shiftbreak        ;;esacdonecount=${count:-5}
redEcho() {    [ -c /dev/stdout ] && {# if stdout is console, turn on color output.echo -ne "\033[1;31m"echo -n "$@"echo -e "\033[0m"    } || echo "$@"}
yellowEcho() {    [ -c /dev/stdout ] && {# if stdout is console, turn on color output.echo -ne "\033[1;33m"echo -n "$@"echo -e "\033[0m"    } || echo "$@"}
blueEcho() {    [ -c /dev/stdout ] && {# if stdout is console, turn on color output.echo -ne "\033[1;36m"echo -n "$@"echo -e "\033[0m"    } || echo "$@"}
# Check the existence of jstack command!if ! which jstack &> /dev/null; then    [ -z "$JAVA_HOME" ] && {        redEcho "Error: jstack not found on PATH!"exit 1    }    ! [ -f "$JAVA_HOME/bin/jstack" ] && {        redEcho "Error: jstack not found on PATH and $JAVA_HOME/bin/jstack file does NOT exists!"exit 1    }    ! [ -x "$JAVA_HOME/bin/jstack" ] && {        redEcho "Error: jstack not found on PATH and $JAVA_HOME/bin/jstack is NOT executalbe!"exit 1    }export PATH="$JAVA_HOME/bin:$PATH"fi
readonly uuid=`date +%s`_${RANDOM}_$$
cleanupWhenExit() {    rm /tmp/${uuid}_* &> /dev/null}trap "cleanupWhenExit" EXIT
printStackOfThreads() {local linelocal count=1while IFS=" " read -a line ; dolocal pid=${line[0]}local threadId=${line[1]}local threadId0x="0x`printf %x ${threadId}`"local user=${line[2]}local pcpu=${line[4]}
local jstackFile=/tmp/${uuid}_${pid}
        [ ! -f "${jstackFile}" ] && {            {if [ "${user}" == "${USER}" ]; then                    jstack ${pid} > ${jstackFile}elseif [ $UID == 0 ]; then                        sudo -u ${user} jstack ${pid} > ${jstackFile}else                        redEcho "[$((count++))] Fail to jstack Busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user})."                        redEcho "User of java process($user) is not current user($USER), need sudo to run again:"                        yellowEcho "    sudo ${COMMAND_LINE[@]}"echocontinuefifi            } || {                redEcho "[$((count++))] Fail to jstack Busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user})."echo                rm ${jstackFile}continue            }        }        blueEcho "[$((count++))] Busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user}):"        sed "/nid=${threadId0x} /,/^$/p" -n ${jstackFile}done}

ps -Leo pid,lwp,user,comm,pcpu --no-headers | {    [ -z "${pid}" ] &&    awk '$4=="java"{print $0}' ||    awk -v "pid=${pid}" '$1==pid,$4=="java"{print $0}'} | sort -k5 -r -n | head --lines "${count}" | printStackOfThreads