Real-time log monitoring and analysis under Linux

Real-time log monitoring and analysis under Linux

In daily system management and troubleshooting, logs are a very important data source. Through real-time monitoring and analysis of system logs, we can detect abnormal situations in time and handle them accordingly. This article will introduce how to perform real-time log monitoring and analysis under Linux, and provide corresponding code examples.

1. Real-time log monitoring

Under Linux, the most commonly used log system is rsyslog. By configuring rsyslog, we can output logs of different applications to specified files and monitor these log files in real time through the tail command.

1. First, you need to ensure that rsyslog is installed and running. You can check the status of rsyslog through the following command:

systemctl status rsyslog

2. Edit the rsyslog configuration file /etc/rsyslog.conf and output the logs that need to be monitored to the specified file. For example, we want to monitor the /var/log/messages file:

#将/var/log/messages文件的日志输出到/var/log/monitored.log :msg,contains,"kernel" /var/log/monitored.log #其他日志默认输出到/var/log/messages *.info;mail.none;authpriv.none;cron.none /var/log/messages

3. Restart the rsyslog service to make the configuration take effect:

service rsyslog restart

4. Use the tail command to Specified log files for real-time monitoring. For example, we want to monitor the /var/log/monitored.log file:

tail -f /var/log/monitored.log

Through the above steps, we can monitor the specified log file in real time.

2. Real-time log analysis

Real-time log monitoring is only the first step. What is more important is to analyze the logs in real time so that problems can be discovered in time and corresponding measures can be taken. Under Linux, we can use some tools to implement log analysis.

1. awk

awk is a powerful text analysis tool that is often used in real-time log analysis. Through awk, we can filter and process logs according to specified conditions.

For example, if we want to filter out log lines containing specific keywords, we can use the following command:

tail -f /var/log/monitored.log | awk '/关键字/'

2. grep

grep is another commonly used Text search tool to quickly find log lines containing specified keywords.

For example, if we want to find log lines containing the keyword "error", we can use the following command:

tail -f /var/log/monitored.log | grep "error"

3. sed

sed is a A streaming text editor that can process text according to specified rules. Through sed, we can perform operations such as replacing and deleting logs.

For example, if we want to replace the keyword "warning" with "warning" in the log line, we can use the following command:

tail -f /var/log/monitored.log | sed 's/warning/警告/g'

Through the combination of the above tools, we can do more complex Real-time log analysis.

Summary:

Real-time log monitoring and analysis play an important role in system management and troubleshooting. By configuring rsyslog and using tools such as awk, grep, sed, etc., we can achieve real-time monitoring and analysis of Linux system logs. This allows us to detect system anomalies in a timely manner and take appropriate measures to ensure the normal operation of the system.

The above is an introduction to real-time log monitoring and analysis under Linux. I hope it will be helpful to readers.

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