squid内存监控脚本

oom_of_squid

用于监控服务器上的squid进程，保证对用户服务的稳定。

此进程意欲以守护进程模式运行，可以这样使用：./oom_of_squid &

主要功能：

监控配置过的每个squid进程，保证它的内存占用看似正常；
确保进程PID和PID文件一致；
squid进程挂掉后启动之；
squid进程占用的内存超过设置的阀值则重启之；
系统可用内存低于阀值，则选择一个squid进程重启之；
默认每3秒检查一次；

注意事项：

`echo squid7[0-9].conf`在gentoo和CentOS上的行为不一样，到CentOS下应用可能需要改为`ls squid7[0-9].conf`；
/proc/$PID/comm 在较新的内核上才有这个接口，使用旧内核需要另想办法；
/etc/init.d/squid_multi_instance是我重写过的进程管理脚本（还有bug），使用“标准”脚本的人需要自己改一下；
系统可用内存阀值应该适当高于系统自身的oom阀值；
用于全内存式缓存更好，因为不用顾忌状态文件的同步。
我设置的配置文件中，squid7[0-9].conf是carp-child，用于缓存文件；squid8[0-9].conf是carp-parent，用于决定URL在集群中的分布。

附件为脚本。望用的上的同仁多提宝贵意见！！！

#!/bin/bash # 功能: #    在系统可用内存很小时选取一个squid进程重启 #    检查各进程健康状况 MAIL="[email protected]"        # 设置自己的邮箱 MAIL_FROM="[email protected]" CHECK_INTERVAL="3s"        # 检查时间间隔 THRESHOLD_LOW_MEM="90"            # MB,低内存阀值; 必须大于vm.min_free_kbytes THRESHOLD_CHILD_MAX_MEM="200"    # MB,child持有内存大于此值就重启 THRESHOLD_EMERG="100"            # MB,LEVEL="emerg"时重启进程的阀值 LEVEL="normal"    # 内存级别,可用内存较低时设置为emerg; 正常情况下应该是空变量 LOG="$0.log" # 探测配置文件,70-79之间的端口为parent,80-87为child CONFIG_LOCATION="/etc/squid/" PARENT_CONF=$(cd $CONFIG_LOCATION; echo squid7[0-9].conf) CHILD_CONF=$(cd $CONFIG_LOCATION; echo squid8[0-9].conf) ALL_CONF="$PARENT_CONF $CHILD_CONF" # disable killing by oom echo "-17" > /proc/self/oom_adj all_free_mem() {     free -m | awk '/^Mem:/ {print ($4 + $6 + $7)}'    # 单位是MB } squid_instance_mem() {     INSTANCE=${CONF%.conf}     PID_FILE="/var/run/$INSTANCE.pid"     [[ -e $PID_FILE ]] && PID_FROM_FILE=`cat $PID_FILE` || PID_FROM_FILE=""     # 检查名称和进程号是否对应     if [ -e $PID_FILE ]; then         [[ x$PID_FROM_FILE != "x" ]] && grep -q squid /proc/$PID_FROM_FILE/comm || false     else         echo "$INSTANCE pid file not match to squid" >> $LOG     fi     # 占用的内存数量     RSS=`awk '/^VmRSS:/ {printf "%d\n", $2/1024}' /proc/$PID_FROM_FILE/status` } keep_processes_health() {     # 检查所有进程,如果挂了,修正一下     for CONF in $ALL_CONF; do         INSTANCE=${CONF%.conf}         PID_FILE="/var/run/$INSTANCE.pid"         STATE_FILE="/var/lib/init.d/started/$INSTANCE"         [[ -e $PID_FILE ]] && PID_FROM_FILE=`cat $PID_FILE` || PID_FROM_FILE=""         PID_RUNNING=`ps axo user,pid,cmd | awk '/^squid/ && /'$CONF'/ {print $2}'`         if [ x$PID_RUNNING = "x" ]; then             # 进程不存在: 启动进程             process_state="not_running"             echo "`date +%F\ %T` $INSTANCE state is $process_state, restarted" >> $LOG             [[ -e $PID_FILE ]] && /bin/rm -f $PID_FILE             [[ -e $STATE_FILE ]] && /bin/rm -f $STATE_FILE             /etc/init.d/squid_multi_instance start ${INSTANCE#squid} >/dev/null 2>&1             notify_admin &         elif [ x$PID_FROM_FILE = "x" ]; then             # pid文件有问题: 修正             process_state="bad_pid_file"             if echo $PID_RUNNING > $PID_FILE; then                 process_state="good"                 echo "fixed pid file of $INSTANCE at `date +%F\ %T`" >> $LOG             else                 echo "can not write $PID_FILE" >> $LOG                 process_state="pid_file_not_writeable"                 notify_admin &             fi         elif [ x$PID_FROM_FILE != x$PID_RUNNING ]; then             # 什么情况下会这样呢...             process_state="pid_not_equal"             if echo $PID_RUNNING > $PID_FILE; then                 echo "fixed $process_state of $INSTANCE at `date +%F\ %T`" >> $LOG                 notify_admin &             else                 echo "can not write $PID_FILE" >> $LOG                 process_state="$process_state pid_file_not_writeable"                 notify_admin &             fi         elif [ x$PID_FROM_FILE = x$PID_RUNNING ]; then             # 运行良好             process_state="good"             continue         else             process_state="unknow"             notify_admin &         fi     done     unset process_state } restart_process() {     INSTANCE=${CONF%.conf}     /etc/init.d/squid_multi_instance restart ${INSTANCE#squid} >/dev/null 2>&1     notify_admin & } pick_and_restart_parent() {     # 重启占用内存最大的进程     for CONF in $PARENT_CONF; do         squid_instance_mem         PARENT_MEM="$PARENT_MEM\n$RSS $CONF"     done     PARENT_MEM_MAX=`echo -e $PARENT_MEM | sort -n | tail -1`     if [ -n $PARENT_MEM_MAX ]; then         CONF=`echo $PARENT_MEM_MAX | awk '{print $2}'`         restart_process         echo "restarted parent ${CONF%.conf} at `date +%F\ %T`" >> $LOG     else         echo "unknow error in pick_and_restart_parent" >> $LOG     fi } pick_and_restart_child() {     # 正常情况下重启内存大于300M的进程; 紧急情况下重启大于100M的进程     for CONF in $CHILD_CONF; do         squid_instance_mem         if [ $RSS -gt $THRESHOLD_CHILD_MAX_MEM ]; then             process_state="over_THRESHOLD_CHILD_MAX_MEM"             echo "$process_state restarted child ${CONF%.conf} at `date +%F\ %T`" >> $LOG             restart_process         else             true         fi     done     if [ x$LEVEL = "xemerg" ]; then         for CONF in $CHILD_CONF; do             squid_instance_mem             [[ $RSS -gt $THRESHOLD_EMERG ]] && (process_state="over_THRESHOLD_EMERG"; restart_process)         done     else         true     fi } pick_and_restart_one() {     # restart a child first     pick_and_restart_child          # memory still low, restart a parent     [[ `all_free_mem` -lt $THRESHOLD_LOW_MEM ]] && pick_and_restart_parent          # memory still low, restart all child     [[ `all_free_mem` -lt $THRESHOLD_LOW_MEM ]] && \     (CONF="child"; restart_process) } notify_admin() {     sendmail -t -f $MAIL_FROM <<EOF To: $MAIL From: $MAIL_FROM Subject: $INSTANCE on `hostname` restarted 重启过了 `hostname` 上的 $INSTANCE 进程 $INSTANCE 的最后状态为: $process_state 当前系统总剩余内存为: `all_free_mem` . EOF } while true; do     keep_processes_health     # child占用内存大于THRESHOLD_CHILD_MAX_MEM就重启,不等总内存过低     pick_and_restart_child     if [ `all_free_mem` -lt $THRESHOLD_LOW_MEM ]; then         LEVEL="emerg"         echo "low memory at `date +%F\ %T`" >> $LOG         pick_and_restart_one     else         LEVEL="normal"         sleep $CHECK_INTERVAL     fi done # vim: set sw=4 ts=4: