Resources
4 min read
Linux is an open-source operating system kernel originally created in 1991. It has a reputation for being versatile, stable, and secure, hence its wide use on computing devices, beginning from servers and mainframes down to desktop computers, smartphones, and embedded devices. The broad uses for Linux and its popularity have led to the demand for effective monitoring.
To conduct Linux monitoring, users collect, store, and analyze Linux logs to enhance security, troubleshooting processes, and compliance, facilitating effective Linux log management. By implementing comprehensive Linux log management and Linux logging practices, organizations can attain actionable insights from log data, enhance operational efficiency, and improve overall system governance.
Contents
What are Linux Logs?
Linux logs are records of system events, processes, and activities that transpire on a Linux-based operating system. These logs hold great importance in describing the health, security, and performance of the system and hence help administrators and developers in the troubleshooting process, monitoring of the system, and compliance with the security policy.
Through the analysis of Linux logs, administrators can identify errors, track user activity, detect breaches in security, and improve system performance to enhance the overall stability and reliability of Linux-based environments.
The Most Critical Linux Log Types to Monitor
Monitoring various types of Linux logs is important for maintaining its performance and security, but with an extensive range of logs to monitor it can be challenging to know what to focus on. So, we’ve outlined the most critical Linux log types to monitor to ensure the smooth operation of Linux-based systems in production environments.
Syslog (/var/log/syslog)
Syslog includes general system messages, such as those related to kernel messages, system daemons, and application logs. Monitoring syslog gives you the ability to understand the state of the system, resource use, and any issues with hardware failure, disk failure, or software failure. It is the central place for troubleshooting systems-level issues.
Auth Logs (/var/log/auth.log)
Auth logs include authentication messages, for example, user logins, authentication failures, and sudo commands. By monitoring auth logs, it is possible to track attempts at unauthorized access, brute force attacks, and other suspicious user activities that are used in further detection and prevention of security breaches and compliance violations.
Secure Logs (/var/log/secure)
Secure logs, also referred to as authentication logs, are the messages emanating from security that deal with user authentication, SSH sessions, and privilege escalation. It is crucial to monitor secure logs to identify critical security events, including unsuccessful login efforts, SSH key authentication, and account lockout, that will make it possible to react immediately to a threatening incident and vulnerability.
Kernel Logs (/var/log/kern.log)
The kernel logs contain the messages that the Linux kernel generates, such as hardware-related events, errors from device drivers, and system crashes. Monitoring the kernel logs helps diagnose hardware failures, driver issues, and kernel panics to enable administrators to take corrective actions to prevent system downtime and data loss.
Application Logs (e.g., Apache, Nginx, MySQL, etc.)
Application logs contain messages generated by user-installed applications and services, including web servers, databases, and custom applications. Monitoring application logs provides insights into application performance, user interactions, and error conditions, facilitating troubleshooting, performance optimization, and capacity planning.
Systemd Logs (/var/log/journal)
Systemd logs consist of messages that are generated by the systemd init system, such as service start/stop events, system boot messages, and systemd unit failures. Monitoring of systemd logs helps to track the availability of services, diagnose service failures, and troubleshoot system initialization problems, thus ensuring the reliability and smooth operation of systemd-managed services.
Security Logs (/var/log/security)
Security logs are those that contain messages regarding security events that occur, including firewall activities, IDS/IPS alerts, and checks performed on the integrity of the system. Watching these security logs detects and provides action on the detection of security incidents, malware infections, and unauthorized access attempts, hence boosting the general security of the Linux system.
Why You Should Conduct Linux Logging
With Linux Logging your organization can attain a host of benefits, to improve the overall performance, stability, and security of your Linux system. Firstly, Linux logging reveals important insights to be drawn from the behaviors of systems. These can be utilized by administrators for effective troubleshooting and debugging of issues. Analyzing the log files, an administrator can detect error messages, warnings, and anomalies in order to locate problems' causes and apply the corresponding correction actions to resolve issues on time.
In addition to this, Linux logging facilitates ongoing monitoring of system performance statistics, resource consumption, and application behavior. With performance being tracked in CPU usage, memory consumption, disk I/O, and network traffic, administrators can pinpoint performance bottlenecks and optimize system configuration to ensure proper resource allocation to meet workload demands.
Lastly, monitoring Linux logs helps bring in continuous improvement and optimization of the configuration of systems, software applications, and processes of operation. Analyzing log data enables administrators to determine where optimization can be implemented, what best practices can be instantiated, and which system parameters can be fine-tuned to improve efficiency, reliability, and security in order to drive operational excellence and business agility.
Linux Log Management Best Practices
Having outlined the benefits and importance of Linux Logging, to attain the most from the process it’s crucial to follow these best practices.
Centralized Logging
Collects log data from multiple sources or applications in one centralized logging system, such as Logit.io. This eases the collection, storage, and analysis of logs, enabling centralized monitoring, search, and alerting across distributed systems.
Log Rotation
Implement the rotation of logs to manage their size and avoid overfilling the disk. Define log rotation policies to archive or rotate log files by size, time, or when specific event triggers are raised, optimizing the use of storage resources and retaining log information for further analysis.
Log Retention Policies
Determine log retention policies that have the log data retention period based on regulatory requirements, operational needs, and business objectives. Define retention periods for different log types, considering factors such as mandates under compliance, forensic requirements, and storage capacity limitations.
Regular Backup and Archiving
Regularly back up and archive logs for historical records and data integrity. Implement backup and archiving procedures to store log data in secure, off-site locations, facilitating disaster recovery, forensic analysis, and compliance auditing in the event of data loss or system failure.
If you've enjoyed this article why not read our Linux Command Cheat Sheet or The Top 60 Log Management Tools next?