最新要做一个对Linux系统日志采集的需求，当然除了Linux的系统日志采集外，还需要转发Tomcat日志，或者Nginx日志等。所以就使用了rsyslog这个比较常用并且功能比较强大的工具。
版本：
Rsyslog V5
Logstash 5.2.2
一、就不做过多的介绍了直接贴测试通过的rsyslog.conf配置文件该配置文件的目录为：
/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
#$ModLoad imudp
#$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.(内核)
kern.* /dev/console
# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!(记录的内核消息、各种服务的公共消息，报错信息等)
*.info;mail.none;authpriv.none;cron.none /var/log/messages
# The authpriv file has restricted access.(包含验证和授权方面信息)
authpriv.* /var/log/secure
# Log all the mail messages in one place.(包含来着系统运行电子邮件服务器的日志信息)
mail.* -/var/log/maillog
# Log cron stuff(每当cron进程开始一个工作时，就会将相关信息记录在这个文件中)
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(自定义的消息)
local7.* /var/log/boot.log
$ModLoad imfile #装载imfile模块
$InputFileName /opt/tomcat/apache-tomcat-8.5.15/logs/catalina.out #读取日志文件
$InputFileTag catalina: #日志写入日志附加标签字符串
$InputFileFacility local5 #日志类型
$InputFileSeverity info #日志等级
$InputFileStateFile ssologs.log_state #定义记录偏移量数据文件名
$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。
$InputFileName /opt/tomcat/apache-tomcat-8.5.15/logs/localhost_access_log.%$year%-%$month%-%$day%.txt #读取日志文件
$InputFileTag access: #日志写入日志附加标签字符串
$InputFileFacility local6 #日志类型
$InputFileSeverity info #日志等级
$InputFileStateFile sssologs.log_state #定义记录偏移量数据文件名
$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）
$InputRunFileMonitor #激活读取，可以设置多组日志读取，每组结束时设置本参数。以示生效。
# ### begin forwarding rule ###
# The statement between the begin ... end define a SINGLE forwarding
# rule. They belong together, do NOT split them. If you create multiple
# forwarding rules, duplicate the whole block!
# Remote Logging (we use TCP for reliable delivery)
#
# An on-disk queue is created for this action. If the remote host is
# down, messages are spooled to disk and sent when it is up again.
#$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
*.* @10.255.0.167:514
# ### end of the forwarding rule ###
# A template to for higher precision timestamps + severity logging
$template SpiceTmpl,"%TIMESTAMP%.%TIMESTAMP:::date-subseconds% %syslogtag% %syslogseverity-text%:%msg:::sp-if-no-1st-sp%%msg:::drop-last-lf%\n"
:programname, startswith, "spice-vdagent" /var/log/spice-vdagent.log;SpiceTmpl
上面文件中：
. @remote-host:514
.即表示转发所有设备的日志信息
@表示使用UDP协议传输
@@表示使用TCP协议传输
找到上面这句去掉前面的#号然后添加对应的IP和端口即可。
例：
. @10.255.0.165:514
如果你只想要转发服务器上的指定设备的日志消息，比如说内核设备，那么你可以在rsyslog配置文件中使用以下声明。
kern.* @10.255.0.165:514
修改完成后执行service rsyslog restart 重新启动rsyslong 即可。
二、Logstash配置
input {
udp {
port => 514
type => syslog
}
}
filter {
if [type] == "syslog" {
grok {
patterns_dir => "/opt/logstash/logstash-5.2.2/patterns"
match => { "message" => "%{SYSLOGTIMESTAMP:timestamp} %{SYSLOGHOST:syslog_hostname} %{DATA:syslog_program}(?:\[%{POSINT:syslog_pid}\])?: %{GREEDYDATA:syslog_message}" }
}
}
}
output{
elasticsearch {
hosts => ["10.255.0.167"]
index => "rsyslog_test"
}
stdout{
codec => rubydebug
}
}
最后更新配置：/etc/init.d/rsyslog restart
附：Logstash的配置很简单只是监听514端口就可以了，但是使用grok切日志才是麻烦的，毕竟那么多种的日志每种都要写对应的正则O(∩_∩)O~
