4.7. Annex: NFVI Faults

Faults in the listed elements need to be immediately notified to the Consumer in order to perform an immediate action like live migration or switch to a hot standby entity. In addition, the Administrator of the host should trigger a maintenance action to, e.g., reboot the server or replace a defective hardware element.

Faults can be of different severity, i.e., critical, warning, or info. Critical faults require immediate action as a severe degradation of the system has happened or is expected. Warnings indicate that the system performance is going down: related actions include closer (e.g. more frequent) monitoring of that part of the system or preparation for a cold migration to a backup VM. Info messages do not require any action. We also consider a type “maintenance”, which is no real fault, but may trigger maintenance actions like a re-boot of the server or replacement of a faulty, but redundant HW.

Faults can be gathered by, e.g., enabling SNMP and installing some open source tools to catch and poll SNMP. When using for example Zabbix one can also put an agent running on the hosts to catch any other fault. In any case of failure, the Administrator should be notified. The following tables provide a list of high level faults that are considered within the scope of the Doctor project requiring immediate action by the Consumer.

Compute/Storage

Fault	Severity	How to detect?	Comment	Immediate action to recover
Processor/CPU failure, CPU condition not ok	Critical	Zabbix		Switch to hot standby
Memory failure/ Memory condition not ok	Critical	Zabbix (IPMI)		Switch to hot standby
Network card failure, e.g. network adapter connectivity lost	Critical	Zabbix/ Ceilometer		Switch to hot standby
Disk crash	Info	RAID monitoring	Network storage is very redundant (e.g. RAID system) and can guarantee high availability	Inform OAM
Storage controller	Critical	Zabbix (IPMI)		Live migration if storage is still accessible; otherwise hot standby
PDU/power failure, power off, server reset	Critical	Zabbix/ Ceilometer		Switch to hot standby
Power degration, power redundancy lost, power threshold exceeded	Warning	SNMP		Live migration
Chassis problem (e.g. fan degraded/failed, chassis power degraded), CPU fan problem, temperature/ thermal condition not ok	Warning	SNMP		Live migration
Mainboard failure	Critical	Zabbix (IPMI)	e.g. PCIe, SAS link failure	Switch to hot standby
OS crash (e.g. kernel panic)	Critical	Zabbix		Switch to hot standby

Hypervisor

Fault	Severity	How to detect?	Comment	Immediate action to recover
System has restarted	Critical	Zabbix		Switch to hot standby
Hypervisor failure	Warning/ Critical	Zabbix/ Ceilometer		Evacuation/switch to hot standby
Hypervisor status not retrievable after certain period	Warning	Alarming service	Zabbix/ Ceilometer unreachable	Rebuild VM

Network

Fault	Severity	How to detect?	Comment	Immediate action to recover
SDN/OpenFlow switch, controller degraded/failed	Critical	Ceilo- meter		Switch to hot standby or reconfigure virtual network topology
Hardware failure of physical switch/router	Warning	SNMP	Redundancy of physical infrastructure is reduced or no longer available	Live migration if possible otherwise evacuation