Kubernetes 101 - Part10 - Plugins I use for managing K8s clusters

Following are some of the kubectl plugins that I use on a daily basis: 

• kubectx

• kail

• kubectl tree

• kubectl images

• kubectl allctx

• kubectl view-cert -A -E

• kubectl get-all

• kubectl neat
  

You can find many useful kubectl plugins here: https://krew.sigs.k8s.io/plugins/

Working with Kubernetes using Python - Part 06 - Create namespace

Following code snipet uses Python client for the kubernetes API to create namespace. You will need to specify the kubeconfig file and the context to use for creating the namespace. This is an example case if you are working with multiple kubeconfig files where multiple K8s clusters could be present in each kubeconfig file.

from kubernetes import client, config
import argparse


def load_kubeconfig(kubeconfig_file, context_name):
    try:
        config.load_kube_config(
            config_file=f"{kubeconfig_file}", context=f"{context_name}"
        )
    except config.ConfigException as err:
        print(err)
        raise Exception("Could not configure kubernetes python client!")
    v1 = client.CoreV1Api()
    return v1


def create_ns(v1, ns_name):
    print("Creating namespace")
    namespace = client.V1Namespace(metadata={"name": ns_name})
    ret = v1.create_namespace(namespace)
    print(ret)


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("-c", "--context", required=True, help="K8s context")
    parser.add_argument("-f", "--file", required=True, help="Kubeconfig file")
    args = parser.parse_args()

    context = args.context

    v1 = load_kubeconfig(args.file, context)

    ns_name = input("Enter namespace name: ")
    create_ns(v1, ns_name)


if __name__ == "__main__":
    main()

Following is sample output:

❯ python3 create_namespace.py -c tkc-admin@tkc -f /Users/vineethac/testing/ccs/tkc.kubeconfig
Enter namespace name: vineethac-test11
Creating namespace
{'api_version': 'v1',
 'kind': 'Namespace',
 'metadata': {'annotations': None,
              'cluster_name': None,
              'creation_timestamp': datetime.datetime(2022, 12, 7, 11, 57, 17, tzinfo=tzutc()),
              'deletion_grace_period_seconds': None,
              'deletion_timestamp': None,
              'finalizers': None,
              'generate_name': None,
              'generation': None,
              'labels': {'kubernetes.io/metadata.name': 'vineetha-test11'},
              'managed_fields': [{'api_version': 'v1',
                                  'fields_type': 'FieldsV1',
                                  'fields_v1': {'f:metadata': {'f:labels': {'.': {},
                                                                            'f:kubernetes.io/metadata.name': {}}}},
                                  'manager': 'OpenAPI-Generator',
                                  'operation': 'Update',
                                  'time': datetime.datetime(2022, 12, 7, 11, 57, 17, tzinfo=tzutc())}],
              'name': 'vineethac-test11',
              'namespace': None,
              'owner_references': None,
              'resource_version': '5518430',
              'self_link': None,
              'uid': '0e9f1211-e09f-4d2d-b475-8995bb0c0907'},
 'spec': {'finalizers': ['kubernetes']},
 'status': {'conditions': None, 'phase': 'Active'}}

Working with Kubernetes using Python - Part 05 - Get pods

Following code snipet uses Python client for the kubernetes API to get all pods and pods under a specific namespace for a given context:

from kubernetes import client, config
import argparse


def load_kubeconfig(context_name):
    config.load_kube_config(context=f"{context_name}")
    v1 = client.CoreV1Api()
    return v1


def get_all_pods(v1):
    print("Listing all pods:")
    ret = v1.list_pod_for_all_namespaces(watch=False)
    for i in ret.items:
        print(i.metadata.namespace, i.metadata.name, i.status.phase)


def get_namespaced_pods(v1, ns):
    print(f"Listing all pods under namespace {ns}:")
    ret = v1.list_namespaced_pod(f"{ns}")
    for i in ret.items:
        print(i.metadata.namespace, i.metadata.name, i.status.phase)


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("-c", "--context", required=True, help="K8s context")
    parser.add_argument("-n", "--namespace", required=False, help="K8s namespace")
    args = parser.parse_args()

    context = args.context
    v1 = load_kubeconfig(context)

    if not args.namespace:
        get_all_pods(v1)
    else:
        get_namespaced_pods(v1, args.namespace)


if __name__ == "__main__":
    main()

Working with Kubernetes using Python - Part 04 - Get namespaces

Following code snipet uses Python client for the kubernetes API to get namespace details from a given context:

from kubernetes import client, config
import argparse


def load_kubeconfig(context_name):
    config.load_kube_config(context=f"{context_name}")
    v1 = client.CoreV1Api()
    return v1


def get_all_namespace(v1):
    print("Listing namespaces with their creation timestamp, and status:")
    ret = v1.list_namespace()
    for i in ret.items:
        print(i.metadata.name, i.metadata.creation_timestamp, i.status.phase)


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("-c", "--context", required=True, help="K8s context")
    args = parser.parse_args()

    context = args.context
    v1 = load_kubeconfig(context)
    get_all_namespace(v1)


if __name__ == "__main__":
    main()

Working with Kubernetes using Python - Part 03 - Get nodes

Following code snipet uses kubeconfig python module to switch context and Python client for the kubernetes API to get cluster node details. It takes the default kubeconfig file, and switch to the required context, and get node info of the respective cluster. 

kubectl commands: 

kubectl config get-contexts
kubectl config current-context
kubectl config use-context <context_name>
kubectl get nodes -o json

Code: 

	# prerequisite: pip3 install kubernetes, pip3 install kubeconfig
	# this sample code snipet can be used to get basic node details of a given list of clusters/ contexts
	from kubernetes import client, config
	from kubeconfig import KubeConfig
	import argparse
	import json
	def get_nodes():
	config.load_kube_config()
	v1 = client.CoreV1Api()
	return v1.list_node(_preload_content=False)
	def switch_context(cluster_name):
	conf = KubeConfig()
	conf.use_context(f"{cluster_name}")
	conf_doc = conf.view()
	return conf.current_context()
	def main():
	"""
	This function will use the default kubeconfig file, and prints basic node details of a given context.
	"""
	parser = argparse.ArgumentParser()
	parser.add_argument(
	"-c", "--cluster", required=True, help="K8s cluster context name"
	)
	args = parser.parse_args()
	all_clusters = args.cluster
	cluster_list = all_clusters.split(",")
	for cluster_name in cluster_list:
	current_context = switch_context(cluster_name)
	print(f"Current context: {current_context}")
	get_nodes_info = get_nodes()
	get_nodes_info_dict = json.loads(get_nodes_info.data)
	for each_node in get_nodes_info_dict["items"]:
	if (
	"node-role.kubernetes.io/control-plane"
	in each_node["metadata"]["labels"]
	):
	role = "Control Plane Node"
	elif "node-role.kubernetes.io/agent" in each_node["metadata"]["labels"]:
	role = "Worker Node"
	print(
	f'{each_node["metadata"]["name"]} - {each_node["status"]["nodeInfo"]["operatingSystem"]} - {role}'
	)
	print("------------------------------------------")
	if __name__ == "__main__":
	main()

view raw get_nodes.py hosted with ❤ by GitHub

Reference:

https://kubeconfig-python.readthedocs.io/en/latest/
https://github.com/kubernetes-client/python

Hope it was useful. Cheers!

Working with Kubernetes using Python - Part 02 - Switch context

Following code snipet uses kubeconfig python module and it takes the default kubeconfig file, and switch to a new context. 

kubectl commands: 

kubectl config get-contexts
kubectl config current-context
kubectl config use-context <context_name>

Code: 

	# prerequisite: pip3 install kubeconfig
	# this code snipet can be used to switch to a different context
	from kubeconfig import KubeConfig
	import argparse
	def main():
	parser = argparse.ArgumentParser()
	parser.add_argument(
	"-c", "--cluster", required=True, help="K8s cluster context name"
	)
	args = parser.parse_args()
	new_context = args.cluster
	conf = KubeConfig()
	print("Kubeconfig file: ", conf.view())
	print("Current context: ", conf.current_context())
	conf.use_context(new_context)
	print("Switched to context: ", conf.current_context())
	if __name__ == "__main__":
	main()

view raw switch_context.py hosted with ❤ by GitHub

Note: If you want to use a specific kubeconfig file, instead of  conf = KubeConfig() 

you can use conf = KubeConfig('path-to-your-kubeconfig')

Reference:

https://kubeconfig-python.readthedocs.io/en/latest/

Hope it was useful. Cheers!

Working with Kubernetes using Python - Part 01 - List contexts

Following code snipet uses Python client for the kubernetes API and it takes the default kubeconfig file, list the contexts, and active context. 

kubectl commands: 

kubectl config get-contexts
kubectl config current-context

Code: 

	# prerequisite: pip3 install kubernetes
	from kubernetes import client, config
	def main():
	"""
	This function will use the default kubeconfig file, list the contexts, and active context.
	"""
	contexts, active_context = config.list_kube_config_contexts()
	if not contexts:
	print("Cannot find any context in kube-config file.")
	return
	contexts = [context["name"] for context in contexts]
	active_index = contexts.index(active_context["name"])
	active_context = active_context["name"]
	print(f"List of contexts: {contexts}")
	print(f"Active context index is: {active_index}")
	print(f"Actice context name is: {active_context}")
	if __name__ == "__main__":
	main()

view raw list_contexts.py hosted with ❤ by GitHub

Note: If you want to use a specific kubeconfig file, instead of  

contexts, active_context = config.list_kube_config_contexts() 

you can use  

contexts, active_context = config.list_kube_config_contexts(config_file="path-to-kubeconfig")

Reference:

https://github.com/kubernetes-client/python

Hope it was useful. Cheers!