checkId: check.logs.rotation.configured plugin: stellaops.doctor.observability severity: warn tags: [observability, logs]

Log Rotation

What It Checks

Verifies that log rotation is configured to prevent disk exhaustion. The check:

Looks for application-level rotation via Logging:RollingPolicy configuration.
Checks for Serilog rolling configuration at Serilog:WriteTo:0:Args:rollingInterval.
On Linux, checks for system-level logrotate at /etc/logrotate.d/stellaops.
Scans log files in the log directory and flags any file exceeding 100MB.
Warns if rotation is not configured and large log files exist or total log size exceeds 200MB.
Reports info if rotation is not configured but logs are still small.

Without log rotation, log files grow unbounded until they exhaust disk space. Disk exhaustion causes cascading failures across all services. Even before exhaustion, very large log files are slow to search and analyze during incident response.

Common Causes

Log rotation not configured in application settings
logrotate not installed or stellaops config missing from /etc/logrotate.d/
Application-level rotation disabled
Rotation threshold set too high
Very high log volume overwhelming rotation schedule

How to Fix

Docker Compose

Set application-level log rotation:

environment:
  Logging__RollingPolicy: "Size"
  Serilog__WriteTo__0__Args__rollingInterval: "Day"
  Serilog__WriteTo__0__Args__fileSizeLimitBytes: "104857600"  # 100MB

Bare Metal / systemd

Option 1 – Application-level rotation in appsettings.json:

{
  "Logging": {
    "RollingPolicy": "Size"
  }
}

Option 2 – System-level logrotate:

sudo cp /usr/share/stellaops/logrotate.conf /etc/logrotate.d/stellaops

# Or create manually:
cat <<EOF | sudo tee /etc/logrotate.d/stellaops
/var/log/stellaops/*.log {
    daily
    rotate 14
    compress
    missingok
    notifempty
    maxsize 100M
}
EOF

Kubernetes / Helm

logging:
  rollingPolicy: "Size"
  maxFileSizeMB: 100
  retainFiles: 14

Verification

stella doctor run --check check.logs.rotation.configured

check.logs.directory.writable — verifies log directory exists and is writable
check.storage.diskspace — verifies sufficient disk space is available