Logging: What Is It and What Is Its Use

If an unknown error has occurred in the operation of a server, computer or software, the logs are looked at first. Log is a text file with information about the actions of software or users, which is stored on a computer or server. It is a chronology of events and their sources, errors and reasons why they happened. You can read and analyze logs using special software.

Logging 

Logging allows you to answer questions about what happened, when and under what circumstances. Without logs, it is difficult to understand why an error occurs if it occurs periodically and only under certain conditions. To make the task easier for administrators and programmers, information is written to the log not only about errors, but also about the reasons for their occurrence.

After the transition to production, the operation of the application must be constantly monitored in order to prevent and quickly respond to potential emergencies. Log analysis is one of the basic tools in the work of IT professionals. It helps to find the sources of many problems, identify conflicts in configuration files, and track information security related events. And most importantly, thanks to the logs, the errors found can be quickly corrected. Therefore, logging is so important when debugging programs, finding sources of problems with application software and databases.

Logs should be recorded during the operation of each IT component.

Here are some typical cases where logs are used:

The administrator is looking for the causes of technical problems, failures in the device or operating system and the unavailability of the site.

The developer conducts debugging, that is, they search for, localize and eliminate errors.

Seo-specialists collect traffic statistics, evaluate the quality of targeted traffic.

The administrator of the online store keeps track of the history of interaction with payment systems and data on changes in orders.

Log Types 

There are different levels and different logging details. When the error is difficult to reproduce, use the most detailed logs; if not required, collect only key information. To work with logs and search for information in huge text data, specialized tools are used.

For convenient work with logs, they are divided into types. This helps you quickly find the right tools and choose the right tools to work with them. For example, allocate:

• system logs, that is, those that are associated with system events;
• server logs that record calls to the server and the errors that occurred during this;
• database logs that record queries to databases;
• mail logs related to incoming / outgoing letters and tracking errors due to which letters were not delivered;

• authorization logs;
• authentication logs;
• application logs installed on these operating systems.

Logs can also be typed according to their importance:

Fatal / critical error – something that needs to be fixed urgently.

Not critical error – errors that do not affect the user.

Warning – warnings, what you need to pay attention to.

Initial information – information about service API calls, database requests, calls to other services.

Where IT Specialists Prefer to Use Logging 

Most IT specialists set up automatic collection, storage, and processing of logs in the cloud storage. The cloud allows you to reproduce events on the target system even if it completely fails.

Let’s explain with an example. Let’s say the file system of one of the virtual machines was damaged and all data on the server was destroyed. Engineers receive a notification about this incident from the monitoring system and restore server performance through backups. After that, they analyze the logs that have been preserved thanks to the remote storage system. They are similar to the black box of an aircraft, as they help specialists reconstruct the sequence of events in an incident, draw conclusions and develop solutions that will prevent such incidents from occurring in the future.

IT engineers also can use logs to analyze user actions. They can restore at any time who and when performed certain actions within the system. To do this, experts use tools that automatically monitor basic security events. For example, if an account with superuser rights appears on Saturday night, the system will immediately register this event and send a notification. Engineers will verify the legitimacy of the new entry to prevent unauthorized access.

Instruments 

Collection, storage, and analysis of logs are performed using special tools. Here are some of those which are popular among the world’s top-class specialists.

Elasticsearch, Logstash, and Kibana 

Logs of all information systems connected to the Managed IT service are stored in a distributed storage based on the ELK solution (Elasticsearch, Logstash and Kibana). The log collection mechanism looks like this: Logstash collects logs and transfers them to storage, Elasticsearch helps to find the necessary lines in these logs, and Kibana visualizes them. All three components are developed based on open source, so they can be modified to fit the needs of the company.

Logstash is an application for working with large amounts of data, collects information from various sources and translates it into a convenient format.

Elasticsearch is a system for information retrieval. Helps to quickly find the desired lines in the storage files.

Kibana is a data visualization and analytics plugin for Elasticsearch. It helps to process information, find patterns and weaknesses in it.

Kibana transforms data into visual graphs

Wazuh

An open source solution for finding logs that correlate with information security threat models. With its help, IT specialists monitor the integrity of IT systems and promptly respond to incidents.

Wazuh helps:

• detect hidden processes of programs that use software vulnerabilities to bypass anti-virus systems;
• automatically block a network attack, and stop malicious processes and files infected with viruses.

Why Every Company Needs Logging 

Logging is another way to effectively monitor the state of the infrastructure. Together with monitoring services, logging significantly saves time for engineers when investigating certain incidents. And most importantly, with the help of log analysis, you can prevent incidents in the future.

Companies that use logging as part of the Managed IT service reduce the overall number of incidents and gain a fundamentally different level of control over their infrastructure.

The service is also convenient for developers who, using simple interfaces, can monitor the performance of their applications in real-time.