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Easily Deploy ELK into CentOS 7

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Last updated on October 26, 2019

The Elastic Stack — formerly known as the ELK Stack — is a collection of open-source software produced by Elastic which allows you to search, analyze, and visualize logs generated from any source in any format, a practice known as centralized logging. Centralized logging can be very useful when attempting to identify problems with your servers or applications, as it allows you to search through all of your logs in a single place. It’s also useful because it allows you to identify issues that span multiple servers by correlating their logs during a specific time frame.

The Elastic Stack has four main components:

  • Elasticsearch: a distributed RESTful search engine which stores all of the collected data.
  • Logstash: the data processing component of the Elastic Stack which sends incoming data to Elasticsearch.
  • Kibana: a web interface for searching and visualizing logs.
  • Beats: lightweight, single-purpose data shippers that can send data from hundreds or thousands of machines to either Logstash or Elasticsearch.

Together, these different components are most commonly used for monitoring, troubleshooting and securing IT environments (though there are many more use cases for the ELK Stack such as business intelligence and web analytics). Beats and Logstash take care of data collection and processing, Elasticsearch indexes and stores the data, and Kibana provides a user interface for querying the data and visualizing it.

Download and Prepare Installation Packages

There are a couple of ways to install ELK stack. One way is to download all packages as show below from online and install them locally.

https://www.elastic.co/downloads


http://www.oracle.com/technetwork/java/javase/downloads/index.html

  • wget https://download.elastic.co/elasticsearch/release/org/elasticsearch/distribution/tar/elasticsearch/2.3.4/elasticsearch-2.3.4.tar.gz
  • wget https://download.elastic.co/logstash/logstash/logstash-2.3.4.tar.gz
  • wget https://download.elastic.co/kibana/kibana/kibana-4.5.3-linux-x64.tar.gz
  • wget –no-cookies –no-check-certificate –header “Cookie: oraclelicense=accept-securebackup-cookie” https://download.oracle.com/otn-pub/java/jdk/13.0.1+9/cec27d702aa74d5a8630c65ae61e4305/jdk-13.0.1_linux-x64_bin.tar.gz -O jdk-8-linux-x64.tar.gz

For JDK download, you might replace “cec27d702aa74d5a8630c65ae61e4305” with the string you find from Oracle JDK download link.

[root@elk-centos7 ~]# ls -l
total 137456
-rw-r–r–. 1 root root 27547169 May 16  2018 elasticsearch-2.3.4.tar.gz
-rw-r–r–. 1 root root     5307 Mar 20  2012 jdk-8u45-linux-x64.tar.gz
-rw-r–r–. 1 root root 33414498 May 16  2018 kibana-4.5.3-linux-x64.tar.gz
-rw-r–r–. 1 root root 79779303 May 16  2018 logstash-2.3.4.tar.gz

In this post, I am going to show you how to use Yum install all those components without downloading them first.

Prerequisites

 

  • One CentOS 7 server set up by following Initial Server Setup with CentOS 7, including a non-root user with sudo privileges and a firewall. The amount of CPU, RAM, and storage that your Elastic Stack server will require depends on the volume of logs that you intend to gather. For the lab purpose, we will be using a VPS with the following specifications for our Elastic Stack server:
    • OS: CentOS 7.5
    • RAM: 4GB
    • CPU: 2
  • Java 8 — which is required by Elasticsearch and Logstash — installed on your server. Note that Java 9 is not supported. 
  • Nginx installed on your server, which you will configure later in this guide as a reverse proxy for Kibana. 

 

Install JDK 8 JRE & JDK

sudo yum install java-1.8.0-openjdk
sudo yum install java-1.8.0-openjdk-devel

note: https://www.digitalocean.com/community/tutorials/how-to-install-java-on-centos-and-fedora#install-openjdk-8

Install Nginx

sudo yum install epel-release
sudo yum install nginx

sudo systemctl start nginx
sudo systemctl enable nginx

Disable firewall

[opc@Linux-CentOS-7 ~]$ sudo -i
[root@Linux-CentOS-7 ~]# systemctl stop firewalld
[root@Linux-CentOS-7 ~]# systemctl disable firewalld.service
Removed symlink /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@Linux-CentOS-7 ~]# sudo systemctl mask –now firewalld
Created symlink from /etc/systemd/system/firewalld.service to /dev/null.
[root@Linux-CentOS-7 ~]#

Install ElasticSearch

[root@Linux-CentOS-7 ~]# sudo rpm –import https://artifacts.elastic.co/GPG-KEY-elasticsearch
[root@Linux-CentOS-7 ~]# sudo vi /etc/yum.repos.d/elasticsearch.repo

/etc/yum.repos.d/elasticsearch.repo
[elasticsearch-6.x]
name=Elasticsearch repository for 6.x packages
baseurl=https://artifacts.elastic.co/packages/6.x/yum
gpgcheck=1
gpgkey=https://artifacts.elastic.co/GPG-KEY-elasticsearch
enabled=1
autorefresh=1
type=rpm-md

[root@Linux-CentOS-7 ~]# sudo yum install elasticsearch

/etc/elasticsearch/elasticsearch.yml
. . .
network.host: localhost
. . .

 

Start ElasticSearch

[root@Linux-CentOS-7 ~]# sudo vi /etc/elasticsearch/elasticsearch.yml
[root@Linux-CentOS-7 ~]# sudo systemctl start elasticsearch
[root@Linux-CentOS-7 ~]# sudo systemctl enable elasticsearch
Created symlink from /etc/systemd/system/multi-user.target.wants/elasticsearch.service to /usr/lib/systemd/system/elasticsearch.service.

Test ES

[root@Linux-CentOS-7 ~]# curl -X GET “localhost:9200”
curl: (7) Failed connect to localhost:9200; Connection refused

[root@Linux-CentOS-7 ~]# curl -X GET “127.0.0.1:9200”
{
“name” : “9Vq4-ng”,
“cluster_name” : “elasticsearch”,
“cluster_uuid” : “bOf93iLYSyqRkijrdHLbyw”,
“version” : {
“number” : “6.8.3”,
“build_flavor” : “default”,
“build_type” : “rpm”,
“build_hash” : “0c48c0e”,
“build_date” : “2019-08-29T19:05:24.312154Z”,
“build_snapshot” : false,
“lucene_version” : “7.7.0”,
“minimum_wire_compatibility_version” : “5.6.0”,
“minimum_index_compatibility_version” : “5.0.0”
},
“tagline” : “You Know, for Search”
}

[root@Linux-CentOS-7 ~]# service nginx restart
Redirecting to /bin/systemctl restart nginx.service
[root@Linux-CentOS-7 ~]# curl -X GET “localhost:9200”
{
  “name” : “9Vq4-ng”,
  “cluster_name” : “elasticsearch”,
  “cluster_uuid” : “bOf93iLYSyqRkijrdHLbyw”,
  “version” : {
    “number” : “6.8.3”,
    “build_flavor” : “default”,
    “build_type” : “rpm”,
    “build_hash” : “0c48c0e”,
    “build_date” : “2019-08-29T19:05:24.312154Z”,
    “build_snapshot” : false,
    “lucene_version” : “7.7.0”,
    “minimum_wire_compatibility_version” : “5.6.0”,
    “minimum_index_compatibility_version” : “5.0.0”
  },
  “tagline” : “You Know, for Search”
}

[root@Linux-CentOS-7 ~]# netstat -tunnpl
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      2842/master
tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN      1/systemd
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      12181/nginx: master
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      3139/sshd
tcp6       0      0 ::1:25                  :::*                    LISTEN      2842/master
tcp6       0      0 :::111                  :::*                    LISTEN      1/systemd
tcp6       0      0 ::1:9200                :::*                    LISTEN      12526/java
tcp6       0      0 127.0.0.1:9200          :::*                    LISTEN      12526/java
tcp6       0      0 :::80                   :::*                    LISTEN      12181/nginx: master
tcp6       0      0 ::1:9300                :::*                    LISTEN      12526/java
tcp6       0      0 127.0.0.1:9300          :::*                    LISTEN      12526/java
tcp6       0      0 :::22                   :::*                    LISTEN      3139/sshd
udp        0      0 0.0.0.0:68              0.0.0.0:*                           2521/dhclient
udp        0      0 0.0.0.0:111             0.0.0.0:*                           1/systemd
udp        0      0 127.0.0.1:323           0.0.0.0:*                           2050/chronyd
udp        0      0 0.0.0.0:927             0.0.0.0:*                           2028/rpcbind
udp6       0      0 :::111                  :::*                                1/systemd
udp6       0      0 ::1:323                 :::*                                2050/chronyd
udp6       0      0 :::927                  :::*                                2028/rpcbind
[root@Linux-CentOS-7 ~]#

Install and Start Kibana

sudo yum install kibana

sudo systemctl enable kibana
sudo systemctl start kibana

Config Kibana

First, use the openssl command to create an administrative Kibana user which you’ll use to access the Kibana web interface. 

echo “kibanaadmin:`openssl passwd -apr1`” | sudo tee -a /etc/nginx/htpasswd.users

Next, we will create an Nginx server block file. As an example, we will refer to this file as elk.conf
sudo vi /etc/nginx/conf.d/elk.conf
This code configures Nginx to direct your server’s HTTP traffic to the Kibana application, which is listening on localhost:5601. Additionally, it configures Nginx to read the htpasswd.users file and require basic authentication. 150.136.225.194 is the public ip for your ELK VM. If you donot have FQDN, you can use public ip for Ngnix to listen your this ELK website.

elk.conf’>/etc/nginx/conf.d/elk.conf
server {
    listen 80;

    server_name 150.136.225.194;

    auth_basic "Restricted Access";
    auth_basic_user_file /etc/nginx/htpasswd.users;

    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;
    }
}

 

Test Kibana

sudo nginx -t

sudo systemctl restart nginx

By default, SELinux security policy is set to be enforced. Run the following command to allow Nginx to access the proxied service:
sudo setsebool httpd_can_network_connect 1 -P

http://150.136.225.194/status
It will prompt you a window to ask your username and password. Username is the one we configured before: kibanaadmin

Install Logstash

sudo yum install logstash

Config Logstash

[root@Linux-CentOS-7 ~]# sudo vi /etc/logstash/conf.d/02-beats-input.conf
[root@Linux-CentOS-7 ~]# sudo vi /etc/logstash/conf.d/10-syslog-filter.conf
[root@Linux-CentOS-7 ~]# sudo vi /etc/logstash/conf.d/10-syslog-filter.conf
[root@Linux-CentOS-7 ~]# sudo vi /etc/logstash/conf.d/30-elasticsearch-output.conf
[root@Linux-CentOS-7 ~]# sudo -u logstash /usr/share/logstash/bin/logstash –path.settings /etc/logstash -t

Sending Logstash logs to /var/log/logstash which is now configured via log4j2.properties

[2019-10-22T01:45:28,603][INFO ][logstash.setting.writabledirectory] Creating directory {:setting=>”path.queue”, :path=>”/var/lib/logstash/queue”}

[2019-10-22T01:45:28,625][INFO ][logstash.setting.writabledirectory] Creating directory {:setting=>”path.dead_letter_queue”, :path=>”/var/lib/logstash/dead_letter_queue”}

Configuration OK

[2019-10-22T01:45:37,738][INFO ][logstash.runner ] Using config.test_and_exit mode. Config Validation Result: OK. Exiting Logstash

[root@Linux-CentOS-7 ~]#

Create a configuration file called 02-beats-input.conf where you will set up your Filebeat input:

sudo vi /etc/logstash/conf.d/02-beats-input.conf

Insert the following input configuration. This specifies a beats input that will listen on TCP port 5044.

/etc/logstash/conf.d/02-beats-input.conf
input {
  beats {
    port => 5044
  }
}

Next, create a configuration file called 10-syslog-filter.conf, which will add a filter for system logs, also known as syslogs:
sudo vi /etc/logstash/conf.d/10-syslog-filter.conf

/etc/logstash/conf.d/10-syslog-filter.conf
filter {
  if [fileset][module] == "system" {
    if [fileset][name] == "auth" {
      grok {
        match => { "message" => ["%{SYSLOGTIMESTAMP:[system][auth][timestamp]} %{SYSLOGHOST:[system][auth][hostname]} sshd(?:\[%{POSINT:[system][auth][pid]}\])?: %{DATA:[system][auth][ssh][event]} %{DATA:[system][auth][ssh][method]} for (invalid user )?%{DATA:[system][auth][user]} from %{IPORHOST:[system][auth][ssh][ip]} port %{NUMBER:[system][auth][ssh][port]} ssh2(: %{GREEDYDATA:[system][auth][ssh][signature]})?",
                  "%{SYSLOGTIMESTAMP:[system][auth][timestamp]} %{SYSLOGHOST:[system][auth][hostname]} sshd(?:\[%{POSINT:[system][auth][pid]}\])?: %{DATA:[system][auth][ssh][event]} user %{DATA:[system][auth][user]} from %{IPORHOST:[system][auth][ssh][ip]}",
                  "%{SYSLOGTIMESTAMP:[system][auth][timestamp]} %{SYSLOGHOST:[system][auth][hostname]} sshd(?:\[%{POSINT:[system][auth][pid]}\])?: Did not receive identification string from %{IPORHOST:[system][auth][ssh][dropped_ip]}",
                  "%{SYSLOGTIMESTAMP:[system][auth][timestamp]} %{SYSLOGHOST:[system][auth][hostname]} sudo(?:\[%{POSINT:[system][auth][pid]}\])?: \s*%{DATA:[system][auth][user]} :( %{DATA:[system][auth][sudo][error]} ;)? TTY=%{DATA:[system][auth][sudo][tty]} ; PWD=%{DATA:[system][auth][sudo][pwd]} ; USER=%{DATA:[system][auth][sudo][user]} ; COMMAND=%{GREEDYDATA:[system][auth][sudo][command]}",
                  "%{SYSLOGTIMESTAMP:[system][auth][timestamp]} %{SYSLOGHOST:[system][auth][hostname]} groupadd(?:\[%{POSINT:[system][auth][pid]}\])?: new group: name=%{DATA:system.auth.groupadd.name}, GID=%{NUMBER:system.auth.groupadd.gid}",
                  "%{SYSLOGTIMESTAMP:[system][auth][timestamp]} %{SYSLOGHOST:[system][auth][hostname]} useradd(?:\[%{POSINT:[system][auth][pid]}\])?: new user: name=%{DATA:[system][auth][user][add][name]}, UID=%{NUMBER:[system][auth][user][add][uid]}, GID=%{NUMBER:[system][auth][user][add][gid]}, home=%{DATA:[system][auth][user][add][home]}, shell=%{DATA:[system][auth][user][add][shell]}$",
                  "%{SYSLOGTIMESTAMP:[system][auth][timestamp]} %{SYSLOGHOST:[system][auth][hostname]} %{DATA:[system][auth][program]}(?:\[%{POSINT:[system][auth][pid]}\])?: %{GREEDYMULTILINE:[system][auth][message]}"] }
        pattern_definitions => {
          "GREEDYMULTILINE"=> "(.|\n)*"
        }
        remove_field => "message"
      }
      date {
        match => [ "[system][auth][timestamp]", "MMM  d HH:mm:ss", "MMM dd HH:mm:ss" ]
      }
      geoip {
        source => "[system][auth][ssh][ip]"
        target => "[system][auth][ssh][geoip]"
      }
    }
    else if [fileset][name] == "syslog" {
      grok {
        match => { "message" => ["%{SYSLOGTIMESTAMP:[system][syslog][timestamp]} %{SYSLOGHOST:[system][syslog][hostname]} %{DATA:[system][syslog][program]}(?:\[%{POSINT:[system][syslog][pid]}\])?: %{GREEDYMULTILINE:[system][syslog][message]}"] }
        pattern_definitions => { "GREEDYMULTILINE" => "(.|\n)*" }
        remove_field => "message"
      }
      date {
        match => [ "[system][syslog][timestamp]", "MMM  d HH:mm:ss", "MMM dd HH:mm:ss" ]
      }
    }
  }
}

Lastly, create a configuration file called 30-elasticsearch-output.conf:

sudo vi /etc/logstash/conf.d/30-elasticsearch-output.conf

Insert the following output configuration. This output configures Logstash to store the Beats data in Elasticsearch, which is running at localhost:9200, in an index named after the Beat used. The Beat used in this tutorial is Filebeat:

/etc/logstash/conf.d/30-elasticsearch-output.conf
output {
  elasticsearch {
    hosts => ["localhost:9200"]
    manage_template => false
    index => "%{[@metadata][beat]}-%{[@metadata][version]}-%{+YYYY.MM.dd}"
  }
}

Test your Logstash configuration with this command:
sudo -u logstash /usr/share/logstash/bin/logstash –path.settings /etc/logstash -t


If there are no syntax errors, your output will display Configruation OK after a few seconds. 







sudo systemctl start logstash
sudo systemctl enable logstash



Installing and Configuring Filebeat

The Elastic Stack uses several lightweight data shippers called Beats to collect data from various sources and transport them to Logstash or Elasticsearch. Here are the Beats that are currently available from Elastic:
  • Filebeat: collects and ships log files.
  • Metricbeat: collects metrics from your systems and services.
  • Packetbeat: collects and analyzes network data.
  • Winlogbeat: collects Windows event logs.
  • Auditbeat: collects Linux audit framework data and monitors file integrity.
  • Heartbeat: monitors services for their availability with active probing.

sudo yum install filebeat



sudo vi /etc/filebeat/filebeat.yml

/etc/filebeat/filebeat.yml

 

...
#output.elasticsearch:
  # Array of hosts to connect to.
  #hosts: ["localhost:9200"]
...
/etc/filebeat/filebeat.yml
output.logstash:
  # The Logstash hosts
  hosts: ["localhost:5044"]

sudo filebeat modules enable system


sudo filebeat modules list




sudo filebeat setup –template -E output.logstash.enabled=false -E ‘output.elasticsearch.hosts=[“localhost:9200”]’

sudo filebeat setup -e -E output.logstash.enabled=false -E output.elasticsearch.hosts=[‘localhost:9200’] -E setup.kibana.host=localhost:5601

sudo systemctl start filebeat
sudo systemctl enable filebeat

curl -X GET ‘http://localhost:9200/filebeat-*/_search?pretty’

Exploring Kibana Dashboards






References

 

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