Monitoring, Metrics and Events Requirements High Level List

Distinction between metrics and events

For the purposes of Platform Service Assurance, it's important to distinguish between metrics and events as well as how they are measured (from a timing perspective).

A Metric is a (standard) definition of a quantity describing the performance and/or reliability of a monitored function, which has an intended utility and is carefully specified to convey the exact meaning of the measured value. A measured value of a metric is produced in an assessment of a monitored function according to a method of measurement. For example the number of dropped packets for a networking interface is a metric.

An Event is defined as an important state change in a monitored function.  The monitor system is notified that an event has occurred using a message with a standard format. The Event notification describes the significant aspects of the event, such as the name and ID of the monitored function, the type of event, and the time the event occurred. For example, an event notification would take place if the link status of a networking device on a compute node suddenly changes from up to down on a node hosting VNFs in an NFV deployment.

Collector requirements:

Polling vs Event capture for the monitoring agent

In the context of the monitoring agent polling the subsystem it's querying. Both polling and event driven updates should be supported with events driven updates being the preferred model to use. This depends on the subsystem you are monitoring, default would be to leverage event based systems where they exist, but polling should be supported as a configuration option that can be selected by the end user.

In the context of the VIM polling the monitoring Agent:

• Fault events should always use a push model, and the mechanism over which events are sent needs to be reliable.
• Telemetry, can be polled or pushed (could be polled to spread the load on the collection side).
• Network (over)load should be taken into consideration as regards which model to use (push  vs pull), you don't want to destabilize the network. push is more scalable overall and preferred for fault management.

Collector configuration

Should be able to dynamically:

• Enable/disable/or restart resource monitoring
• Get values/notifications
• Get capabilities
• Get the list of metrics being collected
• flush the list of metrics
• Set thresholds for resources
• blacklist resources
• support some sort of buffering mechanism, and should be able to configure
• get the timing information for the agent and do aTiming sync if required.

Collector Time stamping support

The Time sent with a sample should be: time stamp at which the value was collected.

Currently there are 2 scenarios as regards time stamps with samples:

1. Where the subsystem we are reading from CAN provide us with the “incident” time (time at which an event occurred) and the collector can provide us with the collection time (time at which a sample was collected): In this case we have the “incident” time for the sample/event and the time when a collector retrieves the sample...

2. where the subsystem we are reading from CANNOT provide us with the “incident” time only the collection time: In this case we only have the time for when the collector retrieves the sample.

The recommendation for collectors where possible is to collect both incident time and collection time and send them with a sample.

For collectd there is only 1 time stamp field. The recommendation is to send the collection time in the collectd time stamp field for values and notifications- BUT where detection time is available to send it in the metadata.

Events Requirements

Timing

Events must be detected within a 10ms interval in order to allow for a 40ms failover time.

Metrics/Events Format

It's important to define a common format that can be used for the list of identified metrics and events that should be monitored/collected in the NFVI.

• + Name
• + Where the Metric/Event is collected (e.g., the measurement point, such as Host/Guest/Both)
• + Parameters (input factors or variables)
• + Scope of measurement coverage
• + Unit(s) of measure or associated severities
• Definition
• Method of Measurement
• Sources of Error
• Comments

In addition to the measurement result, items marked "+" should either be available for collection, or reported with the measurement result.

Information to be collected in conjunction with NFVI Metrics/Events

It's essential to collect some information about the environment that is being monitored as well as the monitoring process(es) themselves in order to associate the mertrics/events with the relevant host.

Host information:

Each host in a deployment should have a Unique identifier that distinguishes it from all other hosts. A UUID can be used in this case.

Monitoring Process information:

Each monitoring process in a deployment should have a Unique Process identifier.

Each monitoring process in a deployment should support the following events:

Each monitoring process in a deployment should support the following Metrics:

NFVI Other/Additional Information

BIOS information

NFVI Events

What about entire node and switch failures?  In terms of service affecting priority, host and switch failures are at the top as they can affect the most VMs / Containers / VNFs...

While the status of switches and hosts might be the domain of services that have a system-wide view, a host-resident component might be part of the monitoring functionality.

Compute

At a minimum the following events should be monitored:

• Machine check exceptions (System, Processor, Memory...) [TODO: Break this down further]
  
  • DIMM corrected and uncorrected Errors

Networking

At a minimum the following events should be monitored for a Networking interface:

• Link Status
• Dropped Receive Packets – An increasing count could indicate the failure or service interruption of an upstream processes.  

vSwitch liveliness

Storage

NFVI Metrics

Compute

At a minimum the following metrics should be collected:

• CPU utilization TODO: Break this down further]
• vCPU utilization TODO: Break this down further]
• Memory utilization TODO: Break this down further]
• vMemory utilization TODO: Break this down further]
• Cache utilization
  • Hits
  • Misses
  • Instructions per clock (IPC)
  • Last level cache utilization
  • Memory Bandwidth utilization
• Platform Metrics (thermals, fan-speed) [TODO: Break this down further]

Networking

At a minimum the following metrics should be collected for a Networking interface:

Networking MIBs

Where possible the metrics, events and information should be supported for the following Networking MIBs:

Virtual Switch Reporting

• Per interface (stats and info mentioned in the tables above) from Open vSwitch/Open vSwitch on DPDK/ VPP should be collected and exposed.

• sflow, Netflow/IPFIX flow telemetry should be supported, collected and exposed.

Storage

Note: collectd plugins df and disk can help here.

The host CPUs, individually or total usage summed across all CPUs