The cnAAA is built on the Kubernetes cluster strategy, which implies that it has adopted the native concepts of containerization, high availability, scalability, modularity, and ease of deployment. To achieve the benefits offered by Kubernetes, cnAAA uses the construct that includes the components such as pods and services.

Depending on your deployment environment, cnAAA deploys the pods on the virtual machines that you have configured. Pods operate through the services that are responsible for the intrapod communications. If the machine hosting the pods fail or experiences network disruption, the pods are terminated or deleted. However, this situation is transient and cnAAA spins new pods to replace the invalid pods.

The following workflow provides a high-level visibility into the host machines, and the associated pods and services. It also represents how the pods interact with each other. The representation might defer based on your deployment infrastructure.

The Protocol Node hosts the radius-ep, which manages ingress (incoming) and egress (outgoing) traffic on the interfaces. Pods for operations and management processes are located in the OAM Node, while the Service Node hosts the cnAAA-engine. Session Nodes contain pods that serve as databases, storing data accessed by other pods. The illustration also shows the services that pods use to facilitate interactions. All pod communications occur over the gRPC interface.

Note	To ensure resiliency, multiple instances of the Protocol and OAM Nodes are created

Kubernetes deployment includes the kubectl command-line tool to manage the resources in the cluster. You can manage the pods, nodes, and services using the CLI.

For performing the maintenance activities, you can use the kubectl drain command to withdraw a node voluntarily. This command prepares the node by evicting or assigning the associated pods to another node with sufficient resources. You can run the kubectl drain on individual or multiple nodes concurrently.

For generic information on the Kubernetes concepts, see the Kubernetes documentation.

For more information on the Kubernetes components in cnAAA, see the following.

• Pods

• Services

This section describes how to associate pods to node and view the pod-related information using the following steps:

1. Associating Pods to the Nodes

2. Viewing the Pod Details and Status

This section describes how to associate a pod to the node based on their labels.

After you have configured a cluster, you can associate pods to the nodes through labels. This association enables the pods to get deployed on the appropriate node based on the key-value pair.

Labels are required for the pods to identify the nodes where they must get deployed and to run the services. For example, when you configure the protocol-layer label with the required key-value pair, the pods get deployed on the nodes that match the key-value pair.

To associate pods to the nodes through the labels, use the following configuration:

config 
  label 
    cdl-layer   
      key key_value 
      value value 
    oam-layer   
      key key_value 
      value value 
    protocol-layer   
      key key_value 
      value value 
    service-layer   
      key key_value 
      value value 
      end 

Sample Configuration

pcf# show running-config label
label protocol-layer key smi.cisco.com/node-type-1
label protocol-layer value protocol
label service-layer key smi.cisco.com/node-type-2
label service-layer value service
label cdl-layer key smi.cisco.com/node-type-3
label cdl-layer value session
label oam-layer key smi.cisco.com/node-type
label oam-layer value oam
pcf#

NOTES:

• If you opt not to configure the labels, then cnAAA assumes the labels with the default key-value pair.

• cdl-layer —Configures the key-value pair parameters for the CDL.

• oam-layer —Configures the key-value pair parameters for the OAM layer.

• protocol-layer —Configures the key-value pair parameters for the protocol layer.

• service-layer —Configures the key-value pair parameters for the service layer.

This section describes how to view the pod details.

If the service requires additional pods, cnAAA creates and deploys the pods. You can view the list of pods that are participating in your deployment through the cnAAA Ops-Center.

You can run the kubectl command from the master node to manage the Kubernetes resources.

• To view the summary of pod details, use this configuration:

  kubectl get pods -A | grep <cpc namespace> 
  kubectl get pods -A -owide | grep <cpc namespace> 
  
  kubectl get pods -A| grep -iv running

• To view the summary of the pod details, use the following configuration:

  kubectl get pods -A -owide | grep <cpc namespace>

Understanding the pod's state lets you determine the current health and prevent the potential risks.

The following table describes the pod's states.