Monitoring

Types of Monitoring

There are 2 types of monitoring that can be implemented into a network; these are:

• Passive - Passive monitoring tools collect data and store from systems. Usually this data will be displayed in graphs and is accessible either through command-line or web interfaces. This sort of monitoring is useful for historical metrics and live monitoring of systems.
• Active - Active monitoring collects and checks metrics; it will then send out notifications if certain thresholds or conditions are met. This form of monitoring is beneficial for ensuring the health of systems; for example, email notifications can be sent out when systems start overheating or if a system is no longer responsive.

Both forms of monitoring are usually necessary in order to ensure that your HPC cluster is running properly, and in full working order.

Metrics

It is worth considering what metrics for the system will be monitored; a few common ones are listed here:

• CPU
  • Load average
  • Idle percentage
  • Temperature
• Memory
  • Used
  • Free
  • Cached
• Disk
  • Free space
  • Used space
  • Swap (free/used/total)
  • Quotas (if configured)
• Network
  • Packets in
  • Packets out

Cloud service providers usually have both passive and active monitoring services available through their cloud management front-end.

Additional Considerations and Questions

• What metrics should be monitored?
• How frequently should metrics be checked?
• What level of notification is required?
  • Escalation upon repeated errors?
  • Acknowledgement of long-running outages?
  • How do we avoid over-saturation of notifications during major outages?
  • What tests will we run to ensure that notifications are working properly?