This document is very abstract about key metrics and their challenges/goals.
Metrics must retain a historical data for capacity planning, SLA calculation, and all metrics will trigger an alert when a threshold is reached. Several thresholds can be combined into a single alert to help in indentifying a root cause. Additionaly, an alert could trigger an action script that would fix an issue without human intervention.
- CPU load average (1, 5, 15): Keep track of CPU usage for capacity planning or find an issue in combination with other metrics.
- RAM usage: Keep track of RAM usage for capacity planning or find an issue in combination with other metrics.
- Disk free space/inodes: Keep track of Disk usage for capacity planning or find any issue in combination with other metrics.
- SMART status: Preventive actions (replacement) maybe needed for a physical disk drive.
- NIC inbound/outbound traffic: Keep track of resource usage for capacity planning or find any issue in combination with other metrics.
- NIC Link Aggregation status: Identify if a NIC or switch could be failing.
- Request per second: Find any abnormal behaviour to detect DDOS (in combination with NIC traffic), or a unusual drop in the RPS due to backend node failing, a network issue, or CPU/RAM overload.
- Error logs: To identify any error within the proxy configuration, or the SSL offloading.
- SSL certificates (public): Validate expiration date, domains, and root certificate authorities.
- Node health checks: Combined with RPS to help in identifiying if a specific issue with a node.
- SSL certificates (internal): Validate expiration date, domains, and root certificate authorities.