kube_info

The kube_info service is designed to act as a real-time proxy for retrieving essential cluster data from the Kubernetes API. It does not rely on caching or scheduled data collection; instead, it queries the Kubernetes API directly whenever a request is made. This ensures that the information retrieved reflects the current state of the cluster.

Node Info and NodePorts API

This API enables you to gather information about Kubernetes nodes and services of the NodePort type. It is built using Flask and communicates directly with the Kubernetes API.

API Endpoints

1. Get Node Information

GET /node-external-ip

• Description: Retrieves the external IP addresses for all nodes in the Kubernetes cluster.
• Response: Returns a list of nodes, each with its name and associated external IP address.

Example Request:

curl -X GET http://<service-ip>:8080/node-external-ip

Example Response:

[
    {
        "external_ip": "xxx.xxx.xxx.xxx",
        "node_name": "node-1"
    },
    {
        "external_ip": "yyy.yyy.yyy.yyy",
        "node_name": "node-2"
    },
    {
        "external_ip": "zzz.zzz.zzz.zzz",
        "node_name": "node-3"
    }
]

GET /node-external-ip/<node_name>

• Description: Retrieves the external IP address for a specific node by its name.
• Path Parameter:
  • node_name: Name of the node for which information is requested.
• Response: Returns the external IP address and name of the specified node.

Example Request:

curl -X GET http://<service-ip>:8080/node-external-ip/node-1

Example Response:

{
    "external_ip": "xxx.xxx.xxx.xxx",
    "node_name": "node-1"
}

2. Get NodePort Services

GET /nodeports

• Description: Retrieves a list of services of type NodePort. The results can be filtered by namespace and labels.
• Query Parameters:
  • namespace (optional): Filter services by the specified namespace.
  • label_selector (optional): A comma-separated list of labels to filter services by, such as app.kubernetes.io/component=myapp,app.kubernetes.io/instance=myapp.
• Response: Returns a list of NodePort services with details for each.

Example Request (all namespaces, no label filter):

curl -X GET http://<service-ip>:8080/nodeports

Example Request (specific namespace):

curl -X GET "http://<service-ip>:8080/nodeports?namespace=default"

Example Request (namespace and label filter):

curl -X GET "http://<service-ip>:8080/nodeports?namespace=myapp&label_selector=app.kubernetes.io/component=server,app.kubernetes.io/instance=myapp"

Example Response:

[
    {
        "name": "myapp-server-http-nodeport",
        "namespace": "myapp",
        "node_port": 30180,
        "port": 8080,
        "port_name": "http",
        "protocol": "TCP",
        "target_port": 80
    }
]

---

Notes

• This API depends on Kubernetes in-cluster configuration, meaning it should be deployed within a Kubernetes cluster.
• Ensure that the service account running this application has appropriate permissions to list nodes and services within the cluster.

Checking API

You can forward the service port to localhost to test the API:

kubectl port-forward service/nodeinfo-service 8080:8080 -n kube-info

curl -X GET http://localhost:8080/node-external-ip

Alternatively, create a temporary pod to test API access within the cluster:

kubectl run curl-pod --rm -it --image=curlimages/curl:8.9.1 -- curl http://kubeinfo-service.kube-info.svc.cluster.local:8080/node-external-ip

Helm