Systemctl Service Logs Setup Using Logrotate

This guide explains how to set up log rotation for a service managed by systemctl using logrotate.

Service Setup in `systemctl`

First, create a systemctl service configuration for your application. Below is an example configuration file for a service named app:

[Unit]
Description=app
After=network.target
 
[Service]
Type=simple
User=ubuntu
Group=ubuntu
StandardOutput=append:/var/log/app/app.log
StandardError=append:/var/log/app/app.log
WorkingDirectory=/var/www/app
ExecStart=/var/www/app/main
Restart=always
 
[Install]
WantedBy=multi-user.target

This configuration:

Defines the service with Description and After directives.
Redirects standard output and error to /var/log/app/app.log.
Sets the working directory and the command to start the service.
Configures the service to always restart if it fails.

Log Rotation Setup

To manage log rotation for the service logs, configure logrotate:

Create a Logrotate Configuration File

Edit or create the logrotate configuration file for your service:
```
sudo nano /etc/logrotate.d/app
```
Add the following configuration:
```
/var/log/app/app.log {
    daily
    missingok
    rotate 7
    compress
    delaycompress
    notifempty
    create 0640 root root
    sharedscripts
    postrotate
        systemctl reload app.service > /dev/null 2>&1 || true
    endscript
}
```
This configuration:
- Rotates the log file daily.
- Keeps 7 rotated log files before deleting the oldest.
- Compresses old logs.
- Skips empty logs.
- Creates new log files with specific permissions and ownership.
- Runs a script to reload the service after rotation.
Prepare Log File and Directory

Ensure the log file and directory have the correct permissions:
```
sudo chmod 644 /var/log/app/app.log
sudo chown root:root /var/log/app/app.log
```
Ensure the directory has appropriate permissions:
```
sudo chmod 755 /var/log/app/
```
Create the log file if it doesn't exist:
```
sudo touch /var/log/app/app.log
```
Restart the service to ensure it is writing logs:
```
sudo systemctl restart app.service
```
Verify Logrotate Functionality

Check the logrotate status file to confirm that the log file is tracked:
```
cat /var/lib/logrotate/status
```
Run logrotate in verbose mode to see detailed output:
```
sudo logrotate -v /etc/logrotate.d/app
```
Run logrotate in debug mode to understand why it might not be working:
```
sudo logrotate -d /etc/logrotate.d/app
```
Manually Trigger Log Rotation

Force a log rotation to test the setup:
```
sudo logrotate -f /etc/logrotate.d/app
```

By following these steps, you will set up log rotation for your service logs, ensuring they are managed and rotated daily.

This document provides a complete setup for managing and rotating logs for a service using logrotate. Adjust the paths and filenames according to your specific requirements.

Ssh & Scp Systemctl Service Python

Systemctl Service Logs Setup Using Logrotate

Service Setup in systemctl

Log Rotation Setup

Service Setup in `systemctl`