Logging and monitoring with Elastic stack on Ubuntu 16.04
Introduction
Elasticsearch is an open source search engine based on Lucene, developed in java. It provides a distributed and multitenant full-text search engine with an HTTP Dashboard web-interface (Kibana) and JSON documents scheme. Elasticsearch is a scalable search engine that can be used to search for all types of documents, including log file. Elasticsearch is the heart of the 'Elastic Stack' or ELK Stack.[1]
Logstash is an open source tool for managing system events and logs. It provides real-time pipelining to collect data. Logstash will collect the log or data, convert all data into JSON documents, and store them in Elasticsearch.
Kibana is a data visualization interface for Elasticsearch. Kibana provides a pretty dashboard (web interfaces), it allows you to manage and visualize all data from Elasticsearch on your own. It's not just beautiful, but also powerful.
In this HOW TO, I will show you how to install and configure Elastic Stack on a single Ubuntu 16.04 server for monitoring server logs and how to install 'Elastic beats' on client PCs with Ubuntu 16.04 and CentOS 7 operating system.
Prerequisite
Ubuntu 16.04 64 bit server with 4GB of RAM, hostname - elk-master
Ubuntu 16.04 64 bit client with 1 GB of RAM, hostname - elk-client1
Step 1 - Install Java
Java is required for the Elastic stack deployment. Elasticsearch requires Java 8. It is recommended to use the Oracle JDK 1.8. We will install Java 8 from a PPA repository.
Install the new package 'python-software-properties' so we can add a new repository easily with an apt command.
sudo apt-get update
sudo apt-get install -y python-software-properties software-properties-common apt-transport-https
Add the new Java 8 PPA repository with the 'add-apt-repository' command, then update the repository.
sudo add-apt-repository ppa:webupd8team/java -y
sudo apt-get update
Install Java 8 from the PPA webpub8 repository.
sudo apt-get install -y oracle-java8-installer
Step 2 - Install and Configure Elasticsearch
In this step, we will install and configure Elasticsearch. Install Elasticsearch from the elastic repository and configure it to run on the localhost IP.
Before installing Elasticsearch, add the elastic repository key to the server.
wget -qO - https://artifacts.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add -
Add elastic 5.x repository to the 'sources.list.d' directory.
echo "deb https://artifacts.elastic.co/packages/5.x/apt stable main" | sudo tee -a /etc/apt/sources.list.d/elastic-5.x.list
Update the repository and install Elasticsearch 5.1 with the apt command below.
sudo apt-get update
sudo apt-get install -y elasticsearch
Elasticsearch is installed. Now go to the configuration directory and edit the elasticsaerch.yml configuration file.
cd /etc/elasticsearch/
nano elasticsearch.yml
Enable memory lock for Elasticsearch by removing the comment on line 43. We do this to disable swapping memory for Elasticsearchto avoid overloading the server.
bootstrap.memory_lock: true
In the 'Network' block, uncomment the network.host and http.port lines.
network.host: localhost
http.port: 9200
Save the file and exit nano.
Now edit the elasticsearch service file for the memory lock mlockall configuration.
nano /usr/lib/systemd/system/elasticsearch.service
Uncomment LimitMEMLOCK line.
LimitMEMLOCK=infinity
Save the file and exit.
Edit the default configuration for Elasticsearch in the /etc/default directory.
nano /etc/default/elasticsearch
Uncomment line 60 and make sure the value is 'unlimited'.
MAX_LOCKED_MEMORY=unlimited
Save and exit.
The Elasticsearch configuration is finished. Elasticsearch will run under localhost IP address with port 9200 and we disabled swap memory by enabling mlockall on the Ubuntu server.
Reload the Elasticsearch service file and enable it to run on the boot time, then start the service.
sudo systemctl daemon-reload
sudo systemctl enable elasticsearch
sudo systemctl start elasticsearch
Wait a sec for Elasticsearch to run, then check the open port on the server, make sure the 'state' for port 9200 is 'LISTEN'.
netstat -plntu
Then check the memory lock to ensure that mlockall is enabled. Also check that Elasticsearch is running with the commands below.
curl -XGET 'localhost:9200/_nodes?filter_path=**.mlockall&pretty'
curl -XGET 'localhost:9200/?pretty'
You will see the results below.
Step 3 - Install and Configure Kibana with Nginx
In this step, we will install and configure Kibana behind a Nginx web server. Kibana will listen on the localhost IP address only and Nginx acts as the reverse proxy for the Kibana application.
Install Kibana with this apt command:
sudo apt-get install -y kibana
Now edit the kibana.yml configuration file.
nano /etc/kibana/kibana.yml
Uncomment the server.port, server.hos and elasticsearch.url lines.
server.port: 5601
server.host: "localhost"
elasticsearch.url: "http://localhost:9200"
Save the file and exit nano.
Add Kibana to run at boot and start it.
sudo systemctl enable kibana
sudo systemctl start kibana
Kibana will run on port 5601 as node application.
netstat -plntu
Kibana installation is done, now we need to install Nginx and configure it as a reverse proxy to be able to access Kibana from the public IP address.
Next, install the Nginx and apache2-utils packages.
sudo apt-get install -y nginx apache2-utils
Apache2-utils is a package that contains tools for the webserver that work with Nginx as well, we will use htpasswd basic authentication for Kibana.
Nginx has been installed. Now we need to create a new virtual host configuration file in the Nginx sites-available directory. Create a new file 'kibana' with nano.
cd /etc/nginx/
vim sites-available/kibana
Paste configuration below.
server {
listen 80;
server_name elk-stack.co;
auth_basic "Restricted Access";
auth_basic_user_file /etc/nginx/.kibana-user;
location / {
proxy_pass http://localhost:5601;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection 'upgrade';
proxy_set_header Host $host;
proxy_cache_bypass $http_upgrade;
}
}
Save the file and exit nano
Create a new basic authentication file with the htpasswd command.
sudo htpasswd -c /etc/nginx/.kibana-user admin
TYPE YOUR PASSWORD
Activate the kibana virtual host by creating a symbolic link from the kibana file in 'sites-available' to the 'sites-enabled' directory.
ln -s /etc/nginx/sites-available/kibana /etc/nginx/sites-enabled/
Test the nginx configuration and make sure there is no error, then add nginx to run at boot time and restart nginx.
nginx -t
systemctl enable nginx
systemctl restart nginx
Step 4 - Install and Configure Logstash
In this step, we will install and configure Logsatash to centralize server logs from client sources with filebeat, then filter and transform all data (Syslog) and transport it to the stash (Elasticsearch).
Install Logstash 5 with the apt command below.
sudo apt-get install -y logstash
Edit the hosts file with nano.
nano /etc/hosts
Add the server IP address and hostname.
10.0.2.15 elk-master
Save the hosts file and exit the editor.
Now generate a new SSL certificate file with OpenSSL so the client sources can identify the elastic server.
cd /etc/logstash/
openssl req -subj /CN=elk-master -x509 -days 3650 -batch -nodes -newkey rsa:4096 -keyout logstash.key -out logstash.crt
Change the '/CN' value to the elastic server hostname.
Certificate files will be created in the '/etc/logstash/' directory.
Next, we will create the configuration files for logstash. We will create a configuration file 'filebeat-input.conf' as input file from filebeat, 'syslog-filter.conf' for syslog processing, and then a 'output-elasticsearch.conf' file to define the Elasticsearch output.
Go to the logstash configuration directory and create the new configuration files in the 'conf.d' directory.
cd /etc/logstash/
nano conf.d/filebeat-input.conf
Input configuration, paste configuration below.
input {
beats {
port => 5443
type => syslog
ssl => true
ssl_certificate => "/etc/logstash/logstash.crt"
ssl_key => "/etc/logstash/logstash.key"
}
}
Save and exit.
Create the syslog-filter.conf file.
nano conf.d/syslog-filter.conf
Paste the configuration below.
filter {
if [type] == "syslog" {
grok {
match => { "message" => "%{SYSLOGTIMESTAMP:syslog_timestamp} %{SYSLOGHOST:syslog_hostname} %{DATA:syslog_program}(?:\[%{POSINT:syslog_pid}\])?: %{GREEDYDATA:syslog_message}" }
add_field => [ "received_at", "%{@timestamp}" ]
add_field => [ "received_from", "%{host}" ]
}
date {
match => [ "syslog_timestamp", "MMM d HH:mm:ss", "MMM dd HH:mm:ss" ]
}
}
}
We use a filter plugin named 'grok' to parse the syslog files.
Save and exit.
Create the output configuration file 'output-elasticsearch.conf'.
nano conf.d/output-elasticsearch.conf
Paste the configuration below.
output {
elasticsearch { hosts => ["localhost:9200"]
hosts => "localhost:9200"
manage_template => false
index => "%{[@metadata][beat]}-%{+YYYY.MM.dd}"
document_type => "%{[@metadata][type]}"
}
}
Save and exit.
When this is done, add logstash to start at boot time and start the service.
sudo systemctl enable logstash
sudo systemctl start logstash
