Logging & Monitoring

Log files

File	Format	Rotation	Description
/var/log/lxc_autoscale.log	Plain text	10 MB, 5 backups	Human-readable scaling events and daemon status.
/var/log/lxc_autoscale.json	JSON	10 MB, 3 backups	Machine-readable events for parsing and dashboards.

Both files rotate automatically when they exceed 10 MB. Rotated files are named .log.1, .log.2, etc.

Real-time monitoring

Watch the plain-text log:

tail -f /var/log/lxc_autoscale.log

Parse the JSON log with jq:

cat /var/log/lxc_autoscale.json | jq .

Filter scaling events for a specific container:

cat /var/log/lxc_autoscale.json | jq 'select(.container_id == "102")'

Log interpretation

Each scaling cycle logs:

• Container CPU and memory usage percentages
• Tier assignment and threshold boundaries
• Scaling actions taken (cores/memory added or removed)
• Warnings when resources cannot be allocated
• Timestamps in the configured timezone (default: UTC)

TIP

Frequent scaling actions may indicate that thresholds are too tight. Increase the gap between cpu_lower_threshold and cpu_upper_threshold to reduce scaling churn.

Secret masking

All log output is processed by a masking filter before being written to any destination (console, file, JSON). The filter redacts values that match common secret patterns:

• Key-value pairs containing password, token, secret, or api_key
• Bearer authorization headers
• Strings passed to sshpass -p
• Long hex or base64 strings (32+ characters)

Redacted values are replaced with ***REDACTED***. This is always active and requires no configuration.

Debug mode

Enable debug logging with the --debug flag:

python lxc_autoscale.py --debug

Or via systemd:

# Edit the service file to add --debug
systemctl edit lxc_autoscale.service
systemctl restart lxc_autoscale.service

Debug mode logs all command executions, cgroup reads, tier evaluations, and scaling decisions. It generates significantly more output and should be used for troubleshooting only.

Web UI

A simple web UI for viewing logs is available at lxc_autoscale/ui.