kubconfig and kubectl
Use kubeconfig files to organize information about clusters, users, namespaces, and authentication mechanisms. The kubectl command-line tool uses kubeconfig files to find the information it needs to choose a cluster and communicate with the API server of a cluster.
The kubectl command-line tool lets you control Kubernetes clusters. For configuration, kubectl looks for a file named config in the $HOME/.kube directory. You can specify other kubeconfig files by setting the KUBECONFIG environment variable or by setting the --kubeconfig flag.
This overview covers kubectl syntax, describes the command operations, and provides common examples. For details about each command, including all the supported flags and subcommands, see the kubectl reference documentation. For installation instructions see installing kubectl.
Client Libraries
An overview of the client libraries for using the Kubernetes API from various programming languages.
To write applications using the Kubernetes REST API, you do not need to implement the API calls and request/response types yourself. You can use a client library for the programming language you are using.
https://kubernetes.io/docs/reference/using-api/client-libraries/
Officially-supported Kubernetes client libraries
JavaScript Library
list all pods
const k8s = require('@kubernetes/client-node');
/* If your machine is installed kubectl, the defualt configuration of the k8s cluster is in $HOME/.kube/config
*/
const kc = new k8s.KubeConfig();
kc.loadFromDefault();
const k8sApi = kc.makeApiClient(k8s.CoreV1Api);
k8sApi.listNamespacedPod('default').then((res) => {
console.log(res.body);
});Python Library
list all pods
from kubernetes import client, config
# Configs can be set in Configuration class directly or using helper utility
config.load_kube_config()
v1 = client.CoreV1Api()
print("Listing pods with their IPs:")
ret = v1.list_pod_for_all_namespaces(watch=False)
for i in ret.items:
print("%s\t%s\t%s" % (i.status.pod_ip, i.metadata.namespace, i.metadata.name))Java
list all pods
import io.kubernetes.client.openapi.ApiClient;
import io.kubernetes.client.openapi.ApiException;
import io.kubernetes.client.openapi.Configuration;
import io.kubernetes.client.openapi.apis.CoreV1Api;
import io.kubernetes.client.openapi.models.V1Pod;
import io.kubernetes.client.openapi.models.V1PodList;
import io.kubernetes.client.util.Config;
import java.io.IOException;
public class Example {
public static void main(String[] args) throws IOException, ApiException{
ApiClient client = Config.defaultClient();
Configuration.setDefaultApiClient(client);
CoreV1Api api = new CoreV1Api();
V1PodList list = api.listPodForAllNamespaces(null, null, null, null, null, null, null, null, null);
for (V1Pod item : list.getItems()) {
System.out.println(item.getMetadata().getName());
}
}
}