用rsyslog的缘由：
1.防止系统崩溃无法获取系统日志分享崩溃原因，用rsyslog可以把日志传输到远程的日志服务器上 2.使用rsyslog日志可以减轻系统压力，因为使用rsyslog可以有效减轻系统的磁盘IO 3.rsyslog使用tcp传输非常可靠，可以对日志进行过滤，提取出有效的日志,rsyslog是轻量级的日志软件，在大量日志写的情况下，系统负载基本上在0.1以下一、安装前准备 1.下载rsyslog-5.6.2 2.准备两台机器(linux或者unix)，一台客户端，一台服务端
服务端和客户端的安装步骤：
#指定安装目录
./configure --prefix=/Application/rsyslog
#编译
make
#安装
make install
#添加lib
echo "/Application/rsyslog/lib/rsyslog" >> /etc/ld.so.conf
#更新lib
ldconfig
#产生配置文件
cp /etc/syslog.conf /etc/rsyslog.conf
#!/bin/bash
#
# rsyslog Starts rsyslogd/rklogd.
#
#
# chkconfig: - 12 88
# description: Syslog is the facility by which many daemons use to log \
# messages to various system log files. It is a good idea to always \
# run rsyslog.
### BEGIN INIT INFO
# Provides: $syslog
# Required-Start: $local_fs $network $remote_fs
# Required-Stop: $local_fs $network $remote_fs
# Default-Stop: 0 1 2 3 4 5 6
# Short-Description: Enhanced system logging and kernel message trapping daemons
# Description: Rsyslog is an enhanced multi-threaded syslogd supporting,
# among others, MySQL, syslog/tcp, RFC 3195, permitted
# sender lists, filtering onany message part, and fine
# grain output format control.
### END INIT INFO
# Source function library.
basedir=/Application/rsyslog
moddir=/Application/rsyslog/lib/rsyslog/
rsyslogdfile=$basedir/sbin/rsyslogd
. /etc/init.d/functions
RETVAL=0
start() {
[ -x $rsyslogdfile ] || exit 5
# Do not start rsyslog when sysklogd is running
if [ -e /var/run/syslogd.pid ] ; then
echo $"Shut down sysklogd before you run rsyslog";
exit 1;
fi
# Source config
if [ -f /etc/sysconfig/rsyslog ] ; then
. /etc/sysconfig/rsyslog
else
SYSLOGD_OPTIONS="-M $moddir"
fi
if [ -z "$SYSLOG_UMASK" ] ; then
SYSLOG_UMASK=077;
fi
umask $SYSLOG_UMASK
echo -n $"Starting system logger: "
daemon $rsyslogdfile $SYSLOGD_OPTIONS
RETVAL=$?
echo
[ $RETVAL -eq 0 ] && touch /var/lock/subsys/rsyslog
return $RETVAL
}
stop() {
echo -n $"Shutting down system logger: "
killproc $rsyslogdfile
RETVAL=$?
echo
[ $RETVAL -eq 0 ] && rm -f /var/lock/subsys/rsyslog
return $RETVAL
}
reload() {
RETVAL=1
syslog=`cat /var/run/rsyslogd.pid 2>/dev/null`
echo -n "Reloading system logger..."
if [ -n "${syslog}" ] && [ -e /proc/"${syslog}" ]; then
kill -HUP "$syslog";
RETVAL=$?
fi
if [ $RETVAL -ne 0 ]; then
failure
else
success
fi
echo
return $RETVAL
}
rhstatus() {
status rsyslogd
}
restart() {
stop
start
}
case"$1"in
start)
start
;;
stop)
stop
;;
restart)
restart
;;
reload|force-reload)
reload
;;
status)
rhstatus
;;
condrestart)
[ -f /var/lock/subsys/rsyslog ] && restart || :
;;
*)
echo $"Usage: $0 {start|stop|restart|reload|force-reload|condrestart}"
exit 2
esac
exit $?
#启动服务
#产生服务文件
chmod +x /etc/init.d/rsyslog
#启动前先把syslog停止
service syslog stop
service rsyslog start
#指定日志文件的拥有者
$FileOwner apache
#使用tcp方式
$ModLoad imtcp # needs to be done just once
#tcp接收连接数为500个
$InputTCPMaxSessions 500
#tcp接收信息的端口
$InputTCPServerRun 514
#为信息加上日志时间
$template logformat,"%TIMESTAMP:::date-mysql% %FROMHOST-IP%%msg%\n"
#定义的日志文件的名称，按照年月日
$template DynFile,"/Application/sdns/log/%$year%%$month%%$day%.log"
#把包含sdns_log标志的信息写到DynFile定义的日志文件里
:rawmsg, contains, "sdns_log" ?DynFile;logformat
#这个表示丢弃包含sdns_log标志的信息
:rawmsg, contains, "sdns_log" ~
配置客户端
vi /etc/rsyslog.conf #在文件开始加上#把包含sdns_log的信息通过tcp发到192.168.1.2 @@表示tcp @表示udp
:rawmsg, contains, "sdns_log" @@192.168.1.2
#这个表示丢弃包含sdns_log标志的信息,防止这个信息写到本机的/var/log/message
:rawmsg, contains, "sdns_log" ~