rsyslog 可以理解为多线程增强版的syslog。 在syslog的基础上扩展了很多其他功能，如数据库支持（MySQL、PostgreSQL、Oracle等）、日志内容筛选、定义日志格式模板等。目前大多数Linux发行版默认也是使用rsyslog进行日志记录。rsyslog提供了三种远程传输协议：
UDP 传输协议 基于传统UDP协议进行远程日志传输，也是传统syslog使用的传输协议； 可靠性比较低，但性能损耗最少， 在网络情况比较差， 或者接收服务器压力比较高情况下， 可能存在丢日志情况。 在对日志完整性要求不是很高，在可靠的局域网环境下可以使用。 TCP 传输协议 基于传统TCP协议明文传输，需要回传进行确认，可靠性比较高； 但在接收服务器宕机或者两者之间网络出问题的情况下，会出现丢日志情况。 这种协议相比于UDP在 可靠性方面已经好很多，并且rsyslog原生支持，配置简单， 同时针对可能丢日志情况，可以进行额外配置提高可靠性，因此使用比较广。 RELP 传输协议 RELP（Reliable Event Logging Protocol）是基于TCP封装的可靠日志消息传输协议； 是为了解决TCP 与 UDP 协议的缺点而在应用层实现的传输协议，也是三者 之中最可靠的。 需要多安装一个包rsyslog-relp以支持该协议。 对于线上服务器，为了日志安全起见，建议使用还是使用 RELP 协议进行传输。rsyslog的简单配置记录（如下将公司防火墙上的日志（UDP）打到IDC的rsyslog日志服务器上）
一、rsyslog服务端的部署 安装rsyslog 程序（rsyslog默认已经在各发行版安装，如果系统中没有的话，可以用yum 进行安装，如下：） [root@zabbix ~]# yum install rsyslog -y 配置： [root@zabbix ~]# cat /etc/rsyslog.conf # rsyslog v5 configuration file # For more information see /usr/share/doc/rsyslog-*/rsyslog_conf.html # If you experience problems, see http://www.rsyslog.com/doc/troubleshoot.html #### MODULES #### $ModLoad imuxsock # provides support for local system logging (e.g. via logger command) $ModLoad imklog # provides kernel logging support (previously done by rklogd) $ModLoad immark # provides --MARK-- message capability # Provides UDP syslog reception $ModLoad imudp #开启udp的514端口。也可以开启tcp的514端口，这里只接受udp的 $UDPServerRun 514 # Provides TCP syslog reception #$ModLoad imtcp #$InputTCPServerRun 514 $WorkDirectory /var/lib/rsyslog $AllowedSender udp, 192.168.17.0/8 #仅仅接收来自192.168.17.0/8网段的主机的udp日志（这个是公司防火墙的ip地址） #### GLOBAL DIRECTIVES #### # Use default timestamp format $ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat $template Remote,"/data/fw_logs/%fromhost-ip%/%fromhost-ip%_%$YEAR%-%$MONTH%-%$DAY%.log" #定义模板，接受日志文件路径，区分了不同主机的日志 :fromhost-ip, !isequal, "127.0.0.1" ?Remote # 过滤server 本机的日志 # File syncing capability is disabled by default. This feature is usually not required, # not useful and an extreme performance hit #$ActionFileEnableSync on # Include all config files in /etc/rsyslog.d/ $IncludeConfig /etc/rsyslog.d/*.conf #### RULES #### # Log all kernel messages to the console. # Logging much else clutters up the screen. #kern.* /dev/console # Log anything (except mail) of level info or higher. # Don't log private authentication messages! *.info;mail.none;authpriv.none;cron.none /var/log/messages # The authpriv file has restricted access. authpriv.* /var/log/secure # Log all the mail messages in one place. mail.* -/var/log/maillog local4.* /data/fw.log # Log cron stuff cron.* /var/log/cron # Everybody gets emergency messages *.emerg * # Save news errors of level crit and higher in a special file. uucp,news.crit /var/log/spooler # Save boot messages also to boot.log local7.* /var/log/boot.log # ### begin forwarding rule ### # The statement between the begin ... end define a SINGLE forwarding # rule. They belong together, do NOT split them. If you create multiple # forwarding rules, duplicate the whole block! # Remote Logging (we use TCP for reliable delivery) # # An on-disk queue is created for this action. If the remote host is # down, messages are spooled to disk and sent when it is up again. #$WorkDirectory /var/lib/rsyslog # where to place spool files #$ActionQueueFileName fwdRule1 # unique name prefix for spool files #$ActionQueueMaxDiskSpace 1g # 1gb space limit (use as much as possible) #$ActionQueueSaveOnShutdown on # save messages to disk on shutdown #$ActionQueueType LinkedList # run asynchronously #$ActionResumeRetryCount -1 # infinite retries if host is down # remote host is: name/ip:port, e.g. 192.168.0.1:514, port optional #*.* @@remote-host:514 # ### end of the forwarding rule ### [root@zabbix ~]# mkdir /data/fw_logs/ [root@zabbix ~]# /etc/init.d/rsyslog restart 二、在公司防火墙（192.168.17.41/42）上配置udp日志输出策略（在防火墙添加rsyslog服务端的ip和514端口） 三、过一会儿，在rsyslog日志服务器上设置的日志目录下就能看到防火墙的日志输出了 [root@zabbix ~]# ll /data/fw_logs/ total 4.0K drwxrwxrwx 4 root root 46 Jul 28 10:40 . drwxr-xr-x. 18 root root 4.0K Jul 28 10:38 .. drwx------ 2 root root 41 Jul 28 10:37 192.168.17.41 drwx------ 2 root root 41 Jul 28 10:40 192.168.17.42 [root@zabbix ~]# ll /data/fw_logs/192.168.17.41 total 16K drwx------ 2 root root 41 Jul 28 10:37 . drwxrwxrwx 4 root root 46 Jul 28 10:40 .. -rw------- 1 root root 13K Jul 28 14:02 192.168.17.41_2017-07-28.log ------------------------------------------------------------------------------------ 可以将上面rsyslog服务端的rsyslog.conf里的ip白名单设置为客户机的ip端，比如： $AllowedSender tcp, 172.18.0.0/16 #表示接收172.18.0.0/16网段的客户机的tcp日志输入，前提是打开tcp的514端口 客户机的配置： 只需要在rsyslog.conf文件里添加下面一行： *.* @172.18.10.20 #后面的ip是rsyslog服务端的ip地址 启动rsyslog日志即可！====================再看一例=======================
以上配置的是将公司防火墙的日志打到rsyslog里。现在有这么一个需求：
公司IDC的另外两台服务器172.19.10.24和172.19.10.25上部署了gitlab、nexus、jenkins、jira和wiki，上面的权限设置的比较杂，很多人都有登录需求。现在需要将登录到这两台服务器上的用户的所有操作过程记录下来，记录达到rsyslog日志里，相当于做用户操作记录的审计工作。
=====================通过rsyslog收集nginx日志到远程服务器上====================
需求说明：通过rsyslog服务将192.168.10.21服务器上的/data/nginx/logs/www.kevin.com-access.log日志实时同步到192.168.10.52服务器上（路径为/data/rsyslog/nginx）。
1）192.168.10.21为rsyslog客户端，即日志的推送端。rsyslog日志是客户机主动将自己的日志推送到远程服务器上。
操作如下：
[root@nginx-server ~]# yum install rsyslog -y
[root@nginx-server ~]# cp /etc/rsyslog.conf /etc/rsyslog.conf.bak
[root@nginx-server ~]# cat /etc/rsyslog.conf
# rsyslog v5 configuration file
# For more information see /usr/share/doc/rsyslog-*/rsyslog_conf.html
# If you experience problems, see http://www.rsyslog.com/doc/troubleshoot.html
#### MODULES ####
$ModLoad imuxsock # provides support for local system logging (e.g. via logger command)
$ModLoad imklog # provides kernel logging support (previously done by rklogd)
#$ModLoad immark # provides --MARK-- message capability
$ModLoad imfile ##装载imfile模块，这一行手动添加
# Provides UDP syslog reception
#$ModLoad imudp
#$UDPServerRun 514
# Provides TCP syslog reception
#$ModLoad imtcp
#$InputTCPServerRun 514
#### GLOBAL DIRECTIVES ####
# Use default timestamp format
$ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat
# File syncing capability is disabled by default. This feature is usually not required,
# not useful and an extreme performance hit
#$ActionFileEnableSync on
# Include all config files in /etc/rsyslog.d/
$IncludeConfig /etc/rsyslog.d/*.conf
#### RULES ####
# Log all kernel messages to the console.
# Logging much else clutters up the screen.
#kern.* /dev/console
# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!
*.info;mail.none;authpriv.none;cron.none;local5.none /var/log/messages ##不记录local5的日志
# The authpriv file has restricted access.
authpriv.* /var/log/secure
# Log all the mail messages in one place.
mail.* -/var/log/maillog
# Log cron stuff
cron.* /var/log/cron
# Everybody gets emergency messages
*.emerg *
# Save news errors of level crit and higher in a special file.
uucp,news.crit /var/log/spooler
# Save boot messages also to boot.log
local7.* /var/log/boot.log
# ### begin forwarding rule ###
# The statement between the begin ... end define a SINGLE forwarding
# rule. They belong together, do NOT split them. If you create multiple
# forwarding rules, duplicate the whole block!
# Remote Logging (we use TCP for reliable delivery)
#
# An on-disk queue is created for this action. If the remote host is
# down, messages are spooled to disk and sent when it is up again.
#$WorkDirectory /var/lib/rsyslog # where to place spool files
#$ActionQueueFileName fwdRule1 # unique name prefix for spool files
#$ActionQueueMaxDiskSpace 1g # 1gb space limit (use as much as possible)
#$ActionQueueSaveOnShutdown on # save messages to disk on shutdown
#$ActionQueueType LinkedList # run asynchronously
#$ActionResumeRetryCount -1 # infinite retries if host is down
# remote host is: name/ip:port, e.g. 192.168.0.1:514, port optional
#*.* @@remote-host:514
# ### end of the forwarding rule ###
user.info /var/log/history
#在文件底部添加下面几行内容
$InputFileName /data/nginx/logs/www.kevin.com-access.log ##读取日志文件（要监控的日志文件）
$InputFileTag web_access ##日志写入日志附加标签字符串
$InputFileSeverity info ##日志等级
$InputFileStateFile /etc/rsyslog.d/stat-access ##记录日志点等信息。(相当于msyql的master.info)文件名变了，
这个StateFile标志必须变，否则无法传输。
$InputFileFacility local5 ##设施类别
$InputFilePollInterval 1 ##检查日志文件间隔（秒）
$InputFilePersistStateInterval 1 ##回写偏移量数据到文件间隔时间（秒）
$InputRunFileMonitor ##激活读取，可以设置多组日志读取，每组结束时设置本参数。以示生效。
local5.* @192.168.10.52 ##代表local5设施的所有级别通过udp协议传送到192.168.10.51
重启rsyslog服务
[root@nginx-server ~]# /etc/init.d/rsyslog restart
关闭系统日志记录器： [确定]
启动系统日志记录器： [确定]
由于作为日志的推送端，rsyslog日志不需要开启514端口（如上在rsyslog.conf文件里没有打开dup或tcp的514端口）
[root@nginx-server ~]# lsof -i:514
[root@nginx-server ~]#
2）192.168.10.52为rsyslog服务端，即日志的接收端。
配置如下：
[root@log-server ~]# yum install rsyslog -y
[root@log-server ~]# cp /etc/rsyslog.conf /etc/rsyslog.conf.bak
# rsyslog configuration file
# For more information see /usr/share/doc/rsyslog-*/rsyslog_conf.html
# If you experience problems, see http://www.rsyslog.com/doc/troubleshoot.html
#### MODULES ####
# The imjournal module bellow is now used as a message source instead of imuxsock.
$ModLoad imuxsock # provides support for local system logging (e.g. via logger command)
$ModLoad imjournal # provides access to the systemd journal
#$ModLoad imklog # reads kernel messages (the same are read from journald)
#$ModLoad immark # provides --MARK-- message capability
# Provides UDP syslog reception
$ModLoad imudp ##载入imudp模块
$UDPServerRun 514 ##开启udp接收并制定端口号
# Provides TCP syslog reception
$ModLoad imtcp ##载入imtcp模块。
$InputTCPServerRun 514 ##开启tcp接收并制定端口号。tcp和udp两个端口模块可以同时使用！
#### GLOBAL DIRECTIVES ####
# Where to place auxiliary files
$WorkDirectory /var/lib/rsyslog
# Use default timestamp format
$ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat
#定义一个模板用来指定接收的日志消息的格式（默认会在记录的日志前加几个字段）
$template SpiceTmpl,"%msg%\n" ##%msg:2:$%为去掉日志开头的空格
#定义一个模板用来指定接收的日志文件的存放路径%……%之间的是定义日志按照年-月-日命名
$template DynaFile,"/data/rsyslog/nginx/%$YEAR%-%$MONTH%-%$DAY%.log"
# File syncing capability is disabled by default. This feature is usually not required,
# not useful and an extreme performance hit
#$ActionFileEnableSync on
# Include all config files in /etc/rsyslog.d/
$IncludeConfig /etc/rsyslog.d/*.conf
# Turn off message reception via local log socket;
# local messages are retrieved through imjournal now.
$OmitLocalLogging on
# File to store the position in the journal
$IMJournalStateFile imjournal.state
#### RULES ####
# Log all kernel messages to the console.
# Logging much else clutters up the screen.
#kern.* /dev/console
# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!
*.info;mail.none;authpriv.none;cron.none;local5.none /var/log/messages ##不记录local5设施的日志
# The authpriv file has restricted access.
authpriv.* /var/log/secure
# Log all the mail messages in one place.
mail.* -/var/log/maillog
# Log cron stuff
cron.* /var/log/cron
# Everybody gets emergency messages
*.emerg :omusrmsg:*
# Save news errors of level crit and higher in a special file.
uucp,news.crit /var/log/spooler
# Save boot messages also to boot.log
local7.* /var/log/boot.log
#接收客户端local5设施传送来的日志并存放到指定位置（位置可用定义的模板。?代表使用动态的模板）
local5.* ?DynaFile;SpiceTmpl
# ### begin forwarding rule ###
# The statement between the begin ... end define a SINGLE forwarding
# rule. They belong together, do NOT split them. If you create multiple
# forwarding rules, duplicate the whole block!
# Remote Logging (we use TCP for reliable delivery)
#
# An on-disk queue is created for this action. If the remote host is
# down, messages are spooled to disk and sent when it is up again.
#$ActionQueueFileName fwdRule1 # unique name prefix for spool files
#$ActionQueueMaxDiskSpace 1g # 1gb space limit (use as much as possible)
#$ActionQueueSaveOnShutdown on # save messages to disk on shutdown
#$ActionQueueType LinkedList # run asynchronously
#$ActionResumeRetryCount -1 # infinite retries if host is down
# remote host is: name/ip:port, e.g. 192.168.0.1:514, port optional
#*.* @@remote-host:514
# ### end of the forwarding rule ###
编辑/etc/sysconfig/rsyslog中"SYSLOGD_OPTIONS="开启远程日志接收功能
[root@log-server ~]# cat /etc/sysconfig/rsyslog
# Options for rsyslogd
# Syslogd options are deprecated since rsyslog v3.
# If you want to use them, switch to compatibility mode 2 by "-c 2"
# See rsyslogd(8) for more details
SYSLOGD_OPTIONS="-c 5"
创建日志接收过来后定义的存放目录
[root@log-server ~]# mkdir -p /data/rsyslog/nginx
重启rsyslog服务
[root@log-server ~]# /etc/init.d/rsyslog restart
Shutting down system logger: [ OK ]
Starting system logger: [ OK ]
[root@log-server ~]# lsof -i:514
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
rsyslogd 24594 root 2u IPv4 38927639 0t0 TCP *:shell (LISTEN)
rsyslogd 24594 root 3u IPv4 38927635 0t0 UDP *:syslog
rsyslogd 24594 root 4u IPv6 38927636 0t0 UDP *:syslog
rsyslogd 24594 root 5u IPv6 38927640 0t0 TCP *:shell (LISTEN)
查看日志是否接收过来了
[root@log-server ~]# ll /data/rsyslog/nginx/
total 550876
-rw------- 1 root root 483539594 Jun 13 12:58 2018-06-13.log
[root@log-server ~]# tail -2 /data/rsyslog/nginx/2018-06-13.log
1.203.163.198 - [27/Apr/2018:00:17:53 +0800] "POST /scf/%7B%7BloginConfig.loginSubmitUrl%7D%7D HTTP/1.1" 302 0 "https://www.kevin.com/scf/login" Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.62 Safari/537.36 - 0.010 0.003 10.0.54.21:9020 302
1.203.163.198 - [27/Apr/2018:00:17:53 +0800] "POST /scf/%7B%7BloginConfig.loginSubmitUrl%7D%7D HTTP/1.1" 302 0 "https://www.kevin.com/scf/login" Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.62 Safari/537.36 - 0.012 0.003 10.0.54.21:9020 302
=========================温馨提示========================
rsyslog也可以收集多个日志文件，需要注意的是：
$InputFileTag 定义的APPNAME必须唯一，同一台主机上不同的应用应当使用不同的APPNAME，否则会导致新定义的TOKEN和TAG不生效；
$template 定义的模板名必须唯一，否则会导致新定义的TOKEN和TAG不生效；
$InputFileStateFile 定义的StateFile必须唯一，它被rsyslog用于记录文件上传进度，否则会导致混乱；
如下是rsyslog收集多个日志的配置，这里以2个日志文件为例：
日志的推送端配置
[root@external-lb01 ~]# cat /etc/rsyslog.conf .......... $ModLoad imfile ......... *.info;mail.none;authpriv.none;cron.none;local5.none;local4.none /var/log/messages ......... $InputFileName /data/nginx/logs/portal.kevin.com-access.log $InputFileTag portal_access $InputFileSeverity info $InputFileStateFile /etc/rsyslog.d/stat1-access $InputFileFacility local4 $InputFilePollInterval 1 $InputFilePersistStateInterval 1 $InputRunFileMonitor local4.* @192.168.10.52 $InputFileName /data/nginx/logs/www.kevin.com-access.log $InputFileTag web_access $InputFileSeverity info $InputFileStateFile /etc/rsyslog.d/stat-access $InputFileFacility local5 $InputFilePollInterval 1 $InputFilePersistStateInterval 1 $InputRunFileMonitor local5.* @192.168.10.52 重启日志发送端的rsyslog服务 [root@external-lb01 ~]# /etc/init.d/rsyslog restart日志的接收端配置
[root@open-falcon01 ~]# cat /etc/rsyslog.conf ........ $ModLoad imudp $UDPServerRun 514 # Provides TCP syslog reception $ModLoad imtcp $InputTCPServerRun 514 ......... $template SpiceTmpl,"%msg%\n" $template DynaFile,"/data/external-lb/nginx/nginx-access.log" $template SpiceTmpl2,"%msg%\n" $template DynaFile2,"/data/external-lb/portal/portal-access.log" ......... *.info;mail.none;authpriv.none;cron.none;local5.none;local4.none /var/log/messages ......... local5.* ?DynaFile;SpiceTmpl local4.* ?DynaFile2;SpiceTmpl2 重启日志接收端的rsyslog服务 [root@open-falcon01 ~]# /etc/init.d/rsyslog restart 查看，当访问对应对应的url时，就会有转发后的文件产生，并实时有日志内容转发过来 [root@open-falcon01 ~]# ll /data/external-lb/nginx/nginx-access.log -rw------- 1 root root 1067372 Oct 9 10:51 /data/external-lb/nginx/nginx-access.log [root@open-falcon01 ~]# ll /data/external-lb/portal/portal-access.log -rw------- 1 root root 88141 Oct 9 22:26 /data/external-lb/portal/portal-access.log==========================================================================
注意：
a）如果发现日志还没有接收过来，即/data/rsyslog/nginx目录下没有日志产生，就同时重启推送端和接收端的rsyslog服务。确保双方的iptables防火墙和selinux关闭！
b）也可以自行修改接收的日志文件的存放路径，如改为下面的配置：
$template DynaFile,"/data/rsyslog/nginx/nginx-access.log"
则日志收集后存放的文件如下：
[root@log-server ~]# ll /data/rsyslog/nginx/
total 571716
-rw------- 1 root root 483539594 Jun 13 12:58 2018-06-13.log
-rw------- 1 root root 101893593 Jun 13 13:13 nginx-access.log