How to Automate Nginx Log Rotation with Shell Scripts and Logrotate

Log Rotation (Shell Script)

nginx logs are not rotated by default, so long‑running sites accumulate huge log files; therefore logs are usually rotated daily.

Manual log rotation and backup

-rw-r--r-- 1 root root 2.1G May 8 13:57 front_access.log

1. Send a signal to the nginx process to make it create a new log file (the basic log rotation step).

/var/log/nginx/access.log.bak   # backup original log file
nginx reload  # send reopen signal
# The log file defined in the configuration is /var/log/nginx/access.log
# After the signal, nginx creates a new file at the same path for new entries.

2. Generate a large amount of traffic to fill the log (e.g., using a loop or ab).

# for num in {1..10000}; do curl 10.0.0.8; done

ab -c 100 -n 10000 http://10.0.0.8/

3. Check the current number of log lines. cat all-server-accesss.log | wc -l # 20000 4. Rotate the log: rename the current file with a date suffix, then send the USR1 signal to nginx to reopen a fresh log.

cd /var/log/nginx && mv all-server-accesss.log all-server-accesss.log.$(date '+%F')
kill -USR1 $(ps -ef | grep nginx | grep master | awk '{print $2}')
# New log file appears and receives further entries.

Shell script for automated rotation

#!/bin/bash
# Source log directory
logs_path="/var/log/nginx"
# Backup directory (yesterday's date)
back_logs_path="${logs_path}/$(date -d 'yesterday' +'%F')"
mkdir -p "${back_logs_path}"
# Rename old logs with date suffix
cd "${logs_path}" && find . -type f | xargs -I {} mv {} {}.$(date -d 'yesterday' +'%F')
# Move renamed logs to backup directory
cd "${logs_path}" && find . -type f | xargs -I {} mv {} "${back_logs_path}"
# Tell nginx to reopen logs
kill -USR1 `cat /var/run/nginx.pid`

Testing the script

1. List current logs, then rename them with rename to add a date suffix.

ls
rename log log.$(date +%F) *.log

2. Send the USR1 signal to nginx.

nginx -s reopen   # or kill -USR1 $(cat /var/run/nginx.pid)

3. Verify that new log files are created.

Logrotate configuration

logrotate can automate daily rotation, compression, and retention.

/var/log/nginx/*.log {
    daily
    missingok
    rotate 52
    compress
    delaycompress
    notifempty
    create 640 nginx adm
    sharedscripts
    postrotate
        if [ -f /var/run/nginx.pid ]; then
            kill -USR1 `cat /var/run/nginx.pid`
        fi
    endscript
}

Run logrotate -f /etc/logrotate.d/nginx to force rotation, then add a cron job:

0 0 * * * /usr/sbin/logrotate -f /etc/logrotate.d/nginx >> /var/log/nginx/logrotate_nginx.log 2>&1

The above steps provide both a manual and automated solution for splitting and compressing nginx logs on a daily basis.