Logstash

Logstash retrieves, extracts and sends data to the ElasticSearch server.

Logstash needs to be install on all the servers / clients you want to get logs from.

Related topics:

• Logstash grok expressions
• logstash configuration examples

Installation

You can install logstash either manually or as an APT-GET package.

I recommend you to use the manual installation because the automatic one will chroot you in /var/log. If your application is using logs that are somewhere else, then you'll be screwed.

Manual installation (recommended)

Be careful: Logstash version must match the ElasticSearch version for better performances.

• Get Logstash from the official website: http://logstash.net/
• Install it and unpack it into /opt/

cd /tmp
wget https://download.elasticsearch.org/logstash/logstash/logstash-1.4.2.tar.gz
tar xzvf logstash-1.4.2.tar.gz
rm logstash-1.4.2.tar.gz
mv logstash-1.4.2/ /opt/
cd /opt
ln -s /opt/logstash-1.4.2 /opt/logstash

• Create configuration directories

mkdir -p /etc/logstash/conf.d
mkdir /etc/logstash/grok
mkdir /etc/logstash/db
chmod -R 777 /etc/logstash

• touch log file

touch /var/log/logstash.log
chmod -R 777 /var/log/logstash.log

• Create an init.d script

cd /etc/init.d
vim logstash.sh

Parse the following content:

#!/bin/sh
### BEGIN INIT INFO
# Provides: logstash
# Required-Start: $remote_fs $syslog
# Required-Stop: $remote_fs $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Start daemon at boot time
# Description: Enable service provided by daemon.
### END INIT INFO

. /lib/lsb/init-functions

if [ $(id -u) -ne 0 ]; then
	echo -e " " 
	echo -e "!!!!!!!!!!!!!!!!!!!!" 
	echo -e "!! Security alert !!" 
	echo -e "!!!!!!!!!!!!!!!!!!!!" 
	echo -e "You need to be root or have root privileges to run this script!\n\n"
	echo -e " " 
	exit 1
fi

# Where should Logstash keep track of each file?
export SINCEDB_DIR="/etc/logstash/db"

# Logstash params
name="logstash"
logstash_bin="/opt/logstash/bin/logstash"
logstash_conf="/etc/logstash/conf.d/"
logstash_log="/var/log/logstash.log"
pid_file="/var/run/$name.pid"

start () {
	commandOpts="agent -f $logstash_conf --log ${logstash_log} --verbose"
	log_daemon_msg "Starting $name" "$name"
	if start-stop-daemon --start --quiet --oknodo --pidfile "$pid_file" -b -m --exec $logstash_bin -- $commandOpts; then
		log_end_msg 0
	else
		log_end_msg 1
	fi
}
testConfig () {
	echo "#############################"
	echo " Logstash configuration test"
	echo "#############################"
	command="${logstash_bin} -f $logstash_conf --verbose -t"
	$command
}
stop () {
	log_daemon_msg "Stopping $name" "$name"
	start-stop-daemon --stop --quiet --oknodo --pidfile "$pid_file"
}
status () {
	status_of_proc -p $pid_file "" "$name"
}

case $1 in
	start)
		if status; then exit 0; fi
		start
		;;
	stop)
		stop
		;;
	reload)
		stop
		start
		;;
	restart)
		stop
		start
		;;
	status)
		status && exit 0 || exit $?
		;;
	testConfig)
		testConfig
		;;
	*)
		echo "Usage: $0 {start|stop|restart|reload|status|testConfig}"
		exit 1
		;;
esac
exit 0

• Create symlinks

ln -s /etc/init.d/logstash.sh /usr/bin/logstash

• Register application as a service (optional)

cd /etc/init.d
update-rc.d logstash.sh defaults

Automatic installation

Source: http://logstash.net/docs/latest/repositories

• Add Logstash repository: see Sources#ELK
• Install application

apt-get install logstash logstash-contrib

>> Binaries in /opt/logstash

>> Configuration in /etc/logstash/conf.d/

>> Logs in /var/log/logstash/

• Create a folder for logstash to keep track of each file

mkdir -p /etc/logstash/db
chmod -R 777 /etc/logstash/

• Add a new environment variable in your /etc/profile || /etc/environment

Put:

SINCEDB_DIR=/etc/logstash/db

Apply changes:

source /etc/environment

Configuration

Configuration file

You can set your configuration file(s) in /etc/logstash/conf.d/

example:

vim /etc/logstash/conf.d/logstash.conf

Put:

## List of complete inputs | filters | output available on the official website: 
## http://logstash.net/docs/latest/index
 
## Configuration syntax: http://logstash.net/docs/latest/configuration
 
###### Data sources to process #####
input {
	file {
	    path => [ "/home/qa1/catalina.base/logs/vehco/*.log" ]
	    type => "vehco-qa1"
	}
}

filter {
	# REMINDERS:
	#  >> you can check on Kibana the field name to use for each filter.
	#  >> you can find the list of GROK pattern over here: https://github.com/elasticsearch/logstash/blob/v1.4.2/patterns/grok-patterns

	# All lines that does not start with %{TIMESTAMP} or ' ' + %{TIMESTAMP} belong to the previous event
	multiline {
		pattern => "(([\s]+)20[0-9]{2}-)|20[0-9]{2}-"
		negate => true
		what => "previous"
	}	

	# QA1
	if [type] == "vehco-qa1" {
		grok {
			patterns_dir => ["/etc/logstash/grok"]
			match => [
				"message", "^\s*%{TIMESTAMP_ISO8601:timestamp}\s*%{LOGLEVEL:level} (?:(%{USERNAME:thread} %{JAVACLASS:logger}|%{USERNAME:thread} %{WORD:logger}|%{JAVACLASS:logger}|%{WORD:logger}))(?<content>(.|\r|\n)*)"
				]
			add_tag => "vehco-log-qa1"
		}
		# Something wrong occurred !!! :O
		if "_grokparsefailure" in [tags] {
			grok {
				 patterns_dir => "/etc/logstash/grok"
				 match=>[
					"message","(?<content>(.|\r|\n)*)"
					]
				 add_tag => "vehco-log-qa1-grok_error"
	                     }
		}
	}
}
 
output {
	elasticsearch {
		cluster => "VEHCO"
		protocol => "http"
		# port => ""
		host => "172.16.50.223"
		node_name => "vehco-qa"
		index => "vehco-qa-%{+YYYY.MM.dd}"
	}
}

Logstash - Multilines

Multiline filter must be before GROK filter!

No space start

A new event must NOT start with a space.

# All lines starting with a space belong to the previous event
multiline {
       pattern => "^\s"
       negate => false
       what => "previous"
}

Java exceptions

This will make all exceptions belong to the previous event.

# All exceptions belong to the previous event
multiline {
       pattern => "(([^\s]+)Exception.+)|(at:.+)"
       negate => false
       what => "previous"
}

Only LOG4J logs

If you only expect Log4j logs then you know that each line that does NOT start with a %{TIMESTAMP} is NOT a new event.

# All lines that does not start with %{TIMESTAMP} or ' ' + %{TIMESTAMP} belong to the previous event
multiline {
       pattern => "(([\s]+)20[0-9]{2}-)|20[0-9]{2}-"
       negate => true
       what => "previous"
}

Logstash - Common services

More informations about GeoIP: http://logstash.net/docs/latest/filters/geoip

Grok failure

If your Grok expression is wrong the line will be tagged as '_grokparsefailure' .

filter {
	# myApplication
	if [type] == "myApp" {
		grok {
                      ...
		}
		# Something wrong occurred !!! :O Do something else instead!
		if "_grokparsefailure" in [tags] {
			grok {
				 patterns_dir => "/etc/logstash/grok"
				 match=>[
					"message","(?<content>(.|\r|\n)*)"
					]
				 }
		}
	}
}

Apache2

Requirements:

• Make sure your logs are in "/var/log/apache2" or adjust the paths
• Make sure your using the COMBINED logs (default in Apache 2.4+)

Logstash configuration extract:

input {
	file {
	    path => [ "/var/log/apache2/access.log", "/var/log/apache2/ssl_access.log", "/var/log/apache2/other_vhosts_access.log" ]
	    type => "apache-access"
	}
	file {
	    path => "/var/log/apache2/error.log"
	    type => "apache-error"
	}
}

filter {
	# ------------------------ Parse services logs into fields ---------------------------
	# APACHE 2
	if [type] == "apache-access" {
		# To process log data (message's content) using some regex or precompiled GROK pattern
		grok {
			match => [ "message", "%{COMBINEDAPACHELOG}"]
		}
		# To extract log's time according to a date pattern
		date {
			match => [ "timestamp", "dd/MMM/YYYY:HH:mm:ss Z"]
		}
		# Extraction browser information, if available.
		if [agent] != "" {
			useragent {
				source => "agent"
			}
		}
		if [clientip] != "" {
			geoip {
				source => "clientip"        
                                target => "apache_clientip"
                                add_tag => [ "geoip" ]
                        }
                }
	}

	if [type] == "apache-error" {
		grok {
			match => [ "message", "%{APACHEERRORLOG}"]
			# Directory where to find the custom patterns
			patterns_dir => ["/etc/logstash/grok"]
		}
                if [clientip] != "" {
			geoip {
				source => "clientip"        
                                target => "apache_clientip"
                                add_tag => [ "geoip" ]
			}
		}	
	}
}

output { 
   ...
}

IpTables

Requirements:

• Make sure you are logging dropped packets into a dedicated file. See Firewall log dropped

Logstash configuration extract:

input {
	file {
	    path => "/var/log/iptables.log"
	    type => "iptables"
	}
}


filter {
    # IPTABLES
    if [type] == "iptables" {
        grok {
            match => [
                        "message", "%{IPTABLES_IP}",
                        "message", "%{IPTABLES_ICMP}",
                        "message", "%{IPTABLES_GENERIC}"
                     ]
            patterns_dir => ["/etc/logstash/grok"]
        }
        # Something wrong occurred !!! :O
        if "_grokparsefailure" in [tags] {
            grok {
                     patterns_dir => "/etc/logstash/grok"
                     match=>["message", "%{IPTABLES_ERROR}" ]
                     add_tag => "iptables-grok_error"
                 }
        }
        # Default 'geoip' == src_ip. That means it's easy to display the DROPPED INPUT :)
        if [src_ip] != "" {
            geoip {
                source => "src_ip"
                add_tag => [ "geoip" ]
                target => "src_geoip"
            }
        }
        if [dst_ip] != "" {
            geoip {
                source => "dst_ip"
                add_tag => [ "geoip" ]
                target => "dst_geoip"
            }
        }
    }
}

output { 
   ...
}

Fail2ban

Logstash configuration extract:

input {
	file {
	    path => "/var/log/fail2ban.log"
	    type => "fail2ban"
	}
}


filter {
	# Fail2ban
	if [type] == "fail2ban" {
		grok {
			match => ["message", "%{FAIL2BAN}"]
			patterns_dir => ["/etc/logstash/grok"]
		}
                if [ban_ip] != "" {
			geoip {
			        source => "ban_ip"
                                add_tag => [ "geoip" ]
			        target => "ban_geoip"
			}
		}	
	}
}

output { 
   ...
}

Syslog

Logstash configuration extract:

input {
	file {
	    path => [ "/var/log/syslog", "/var/log/auth.log", "/var/log/mail.info" ]
	    type => "syslog"
	}
}


filter {
	# SYSLOG
	if [type] == "syslog" {
		grok {
			match => ["message", "%{SYSLOGBASE}"]
		}
	}
}

output { 
   ...
}

Tomcat

... To be done ...

Logstash (Application logs)

Log4J

input {
	file {
	    path => [ "/home/beta3/catalina.base/logs/vehco/*.log" ]
	    type => "myApp"
	}
}

filter {	
	# All lines that does not start with %{TIMESTAMP} or ' ' + %{TIMESTAMP} belong to the previous event
	multiline {
		pattern => "(([\s]+)20[0-9]{2}-)|20[0-9]{2}-"
		negate => true
		what => "previous"
	}
	
	# myApplication
	if [type] == "myApp" {
		grok {
			patterns_dir => ["/etc/logstash/grok"]
			match => [
				"message", "^\s*%{TIMESTAMP_ISO8601:timestamp}\s*%{LOGLEVEL:level} (?:(%{USERNAME:thread} %{JAVACLASS:logger}|%{USERNAME:thread} %{WORD:logger}|%{JAVACLASS:logger}|%{WORD:logger}))(?<content>(.|\r|\n)*)"
				]
			add_tag => "myApp-log"
		}
		# Something wrong occurred !!! :O
		if "_grokparsefailure" in [tags] {
			grok {
				 patterns_dir => "/etc/logstash/grok"
				 match=>[
					"message","(?<content>(.|\r|\n)*)"
					]
				 }
		}
	}
}

output { 
   ...
}

VEHCO specific patterns

Now that you have some specific GROK patterns, you need to update your Logstash configuration.

input {
	file {
	    path => [ "/var/log/vehco/*.log" ]
	    type => "vehco-rtd"
	}
}


filter {
	# VEHCO-RTD
	if [type] == "vehco-rtd" {
		grok {
			patterns_dir => ["/etc/logstash/grok"]
			match => [
                                    "message", "%{RTD_TERMINAL}",
                                    "message", "%{RTD_AUTH_START}",
                                    "message", "%{RTD_AUTH_DONE}"
                                 ]
		}
	}
}

output { 
   ...
}

[!] Note 1:

Grok will normally break on match == it will stop processing after the first pattern that matches.

[!] Note 2:

You can set generic blob expression as INPUT filters.

Manual commands

The following command(s) are just here for my personal reference:

cd /opt/logstash/bin
./logstash -f /etc/logstash/conf.d/ -t --verbose

References

• Very good webinar from the ElasticSearch team: http://www.elasticsearch.org/webinars/introduction-to-logstash/?watch=1
• Very good blog article: https://home.regit.org/2014/01/a-bit-of-logstash-cooking/
• Grok on-line debugger: http://grokdebug.herokuapp.com/