# Monitoring

### Monitoring applications

Key for where information can be obtained: (K)ubernetes, (5) ae5_tools, (S)ystem/OS, (A)pplication (Ac: canned/automatic, Au: user/custom functionality), A, (W)ebserver, [P]roxy in front or your apps, (?)

- Ensure they stay up
- (Ac) Currently up
- (K) Uptime (duration and percentage)
- (P/Ac/?) User failure rate (number and percentage)
- Resource utilization (under/over-utilization)
- (K) Memory usage
- (K) CPU usage
- (K) Number of times memory limits were reached (approximated by k8s restarts)
- Popularity
- (Ac) Number of visitors
- (Ac) Duration of visits
- (Ac) Bounce rate?
- (Ac) Open sessions
- Responsiveness
- (Ac) Time to first render
- (Ac) Responsiveness inside application
- Fine grained tracking/monitoring
- [Au] Which parts of app are used by visitors?
- [Au] What error conditions are encountered

### Domain conditions

- (Au) Some metric exceeds threshold
- (Au) App raises explicit error condition

## Indicators

- Traffic light
- Speedometer/Gauge
- Donut
- KPI (numeric absolute/change)