Search

Chapter 32. Associating secondary interfaces metrics to network attachments

download PDF

32.1. Extending secondary network metrics for monitoring

Secondary devices, or interfaces, are used for different purposes. It is important to have a way to classify them to be able to aggregate the metrics for secondary devices with the same classification.

Exposed metrics contain the interface but do not specify where the interface originates. This is workable when there are no additional interfaces. However, if secondary interfaces are added, it can be difficult to use the metrics since it is hard to identify interfaces using only interface names.

When adding secondary interfaces, their names depend on the order in which they are added, and different secondary interfaces might belong to different networks and can be used for different purposes.

With pod_network_name_info it is possible to extend the current metrics with additional information that identifies the interface type. In this way, it is possible to aggregate the metrics and to add specific alarms to specific interface types.

The network type is generated using the name of the related NetworkAttachmentDefinition, that in turn is used to differentiate different classes of secondary networks. For example, different interfaces belonging to different networks or using different CNIs use different network attachment definition names.

32.1.1. Network Metrics Daemon

The Network Metrics Daemon is a daemon component that collects and publishes network related metrics.

The kubelet is already publishing network related metrics you can observe. These metrics are:

  • container_network_receive_bytes_total
  • container_network_receive_errors_total
  • container_network_receive_packets_total
  • container_network_receive_packets_dropped_total
  • container_network_transmit_bytes_total
  • container_network_transmit_errors_total
  • container_network_transmit_packets_total
  • container_network_transmit_packets_dropped_total

The labels in these metrics contain, among others:

  • Pod name
  • Pod namespace
  • Interface name (such as eth0)

These metrics work well until new interfaces are added to the pod, for example via Multus, as it is not clear what the interface names refer to.

The interface label refers to the interface name, but it is not clear what that interface is meant for. In case of many different interfaces, it would be impossible to understand what network the metrics you are monitoring refer to.

This is addressed by introducing the new pod_network_name_info described in the following section.

32.1.2. Metrics with network name

This daemonset publishes a pod_network_name_info gauge metric, with a fixed value of 0:

pod_network_name_info{interface="net0",namespace="namespacename",network_name="nadnamespace/firstNAD",pod="podname"} 0

The network name label is produced using the annotation added by Multus. It is the concatenation of the namespace the network attachment definition belongs to, plus the name of the network attachment definition.

The new metric alone does not provide much value, but combined with the network related container_network_* metrics, it offers better support for monitoring secondary networks.

Using a promql query like the following ones, it is possible to get a new metric containing the value and the network name retrieved from the k8s.v1.cni.cncf.io/network-status annotation:

(container_network_receive_bytes_total) + on(namespace,pod,interface) group_left(network_name) ( pod_network_name_info )
(container_network_receive_errors_total) + on(namespace,pod,interface) group_left(network_name) ( pod_network_name_info )
(container_network_receive_packets_total) + on(namespace,pod,interface) group_left(network_name) ( pod_network_name_info )
(container_network_receive_packets_dropped_total) + on(namespace,pod,interface) group_left(network_name) ( pod_network_name_info )
(container_network_transmit_bytes_total) + on(namespace,pod,interface) group_left(network_name) ( pod_network_name_info )
(container_network_transmit_errors_total) + on(namespace,pod,interface) group_left(network_name) ( pod_network_name_info )
(container_network_transmit_packets_total) + on(namespace,pod,interface) group_left(network_name) ( pod_network_name_info )
(container_network_transmit_packets_dropped_total) + on(namespace,pod,interface) group_left(network_name)
Red Hat logoGithubRedditYoutubeTwitter

Learn

Try, buy, & sell

Communities

About Red Hat Documentation

We help Red Hat users innovate and achieve their goals with our products and services with content they can trust.

Making open source more inclusive

Red Hat is committed to replacing problematic language in our code, documentation, and web properties. For more details, see the Red Hat Blog.

About Red Hat

We deliver hardened solutions that make it easier for enterprises to work across platforms and environments, from the core datacenter to the network edge.

© 2024 Red Hat, Inc.