CentOS System Log Files

To get started first follow the steps below:

• Install
• Root access
• Verify the required port is open

Older versions can be found here 7, 6, 5

There are several built in filebeat modules you can use. To enable the system module run.

sudo filebeat modules list
sudo filebeat modules enable system

Additional module configuration can be done using the per module config files located in the modules.d folder, most commonly this would be to read logs from a non-default location

rpm /etc/filebeat/modules.d/

/etc/filebeat/filebeat.yml

We'll be shipping to Logstash so that we have the option to run filters before the data is indexed.
Comment out the elasticsearch output block.

## Comment out elasticsearch output
#output.elasticsearch:
#  hosts: ["localhost:9200"]

No input available! Your stack is missing the required input for this data source Talk to support to add the input

If you have issues starting in the next step, you can use these commands below to troubleshoot.

Let's check the configuration file is syntactically correct by running directly inside the terminal. If the file is invalid, will print an error loading config file error message with details on how to correct the problem.

deb/rpm

sudo  -e -c /etc//.yml

macOS

cd <EXTRACTED_ARCHIVE>
sudo ./ -e -c .yml

Windows

cd <EXTRACTED_ARCHIVE>
.\.exe -e -c .yml

If you don't see data appearing in your Stack after following the steps, visit the Help Centre guide for steps to diagnose no data appearing in your Stack or Chat to support now.

All Logit.io stacks come pre-configured with popular Logstash filters. We would recommend that you add System specific filters if you don't already have them, to ensure enhanced dashboards and modules work correctly.

Edit your Logstash filters by choosing Stack > Settings > Logstash Filters

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" ]
    }
  }
}

Start or restart to apply the configuration changes.

Now you should view your data:

Launch Dashboard

If you don't see logs take a look at How to diagnose no data in Stack below for how to diagnose common issues.

CentOS is a Linux distribution & computing platform that is often compared with Red Hat Enterprise Linux (RHEL).

The main difference between the two is that CentOS lacks the high level of technical support that is supplied as part of the RHEL package.

CentOS is built off of the Red Hat Enterprise Linux’s open source code base, explaining their commonalities and relative compatibility.

Due to this similarity their library versions are identical. This means that binaries that work on RHEL will work on CentOS. If you're using their administration tools you might notice incompatibilities between the two distributions as minor patches are updated at different rates. Large patches & major releases for CentOS are released sporadically & infrequently compared to other Linux distributions (such as Ubuntu & Debian).

CentOS users are typically individuals & businesses that don’t require strong levels of support, certification & training to use this enterprise class Linux distribution successfully.

Our built in CentOS log file analyser is included in our log management platform and is built upon the open source tools Elasticsearch, Logstash & Kibana to ease the processing of large amounts of Linux server data for troubleshooting & root cause analysis.

Logit.io can be used to centralise your Linux log data & alerts on errors to monitor your operating system (OS). The platform can also be used to view logs within Kibana for detailed visualisations & reporting.

If you need any assistance with analysing your CentOS logs we're here to help. Feel free to reach out by contacting the Logit.io support team via live chat & we'll be happy to help you get started.