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

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

Grok expressions

See Logstash grok expressions

Configuration examples

See logstash configuration examples

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/