kr8s#

EffVer Versioning PyPI PyPI - Python Version Kubernetes Version Support PyPI - Wheel PyPI - License

A simple, extensible Python client library for Kubernetes that feels familiar for folks who already know how to use kubectl.

Highlights#

  • API inspired by kubectl for a shallow learning curve.

  • Sensible defaults to reduce boiler plate.

  • No swagger generated code, human readable code only.

  • Has both a standard and an async API that can be used with asyncio and trio.

  • Client caching to reduce passing API objects around.

  • Batteries included by providing useful utilities and methods inspired by kubectl.

Quickstart#

Installation#

$ pip install kr8s

Examples#

See also

See the Examples Documentation for a full set of examples.

List Nodes#

Print out all of the node names in the cluster.

import kr8s

for node in kr8s.get("nodes"):
    print(node.name)
import kr8s.asyncio

for node in await kr8s.asyncio.get("nodes"):
    print(node.name)

Create a Pod#

Create a new Pod.

from kr8s.objects import Pod

pod = Pod({
        "apiVersion": "v1",
        "kind": "Pod",
        "metadata": {
            "name": "my-pod",
        },
        "spec": {
            "containers": [{"name": "pause", "image": "gcr.io/google_containers/pause",}]
        },
    })

pod.create()
from kr8s.asyncio.objects import Pod

pod = await Pod({
        "apiVersion": "v1",
        "kind": "Pod",
        "metadata": {
            "name": "my-pod",
        },
        "spec": {
            "containers": [{"name": "pause", "image": "gcr.io/google_containers/pause",}]
        },
    })

await pod.create()

Scale a Deployment#

Scale the Deployment metrics-server in the Namespace kube-system to 1 replica.

from kr8s.objects import Deployment

deploy = Deployment.get("metrics-server", namespace="kube-system")
deploy.scale(1)
from kr8s.asyncio.objects import Deployment

deploy = await Deployment.get("metrics-server", namespace="kube-system")
await deploy.scale(1)

List Pods by label selector#

Get all Pods from all Namespaces matching a label selector.

import kr8s

selector = {'component': 'kube-scheduler'}

for pod in kr8s.get("pods", namespace=kr8s.ALL, label_selector=selector):
    print(pod.namespace, pod.name)
import kr8s

selector = {'component': 'kube-scheduler'}

for pod in await kr8s.asyncio.get("pods", namespace=kr8s.ALL, label_selector=selector):
    print(pod.namespace, pod.name)

Add a label to a Pod#

Add the label foo with the value bar to an existing Pod.

from kr8s.objects import Pod

pod = Pod("kube-apiserver", namespace="kube-system")
pod.label({"foo": "bar"})
from kr8s.asyncio.objects import Pod

pod = await Pod("kube-apiserver", namespace="kube-system")
await pod.label({"foo": "bar"})

Generate a Pod#

Generate a simple Pod with a couple of keyword arguments.

from kr8s.objects import Pod

pod = Pod.gen(name="example-1", image="nginx:latest")
pod.create()
from kr8s.asyncio.objects import Pod

pod = await Pod.gen(name="example-1", image="nginx:latest")
await pod.create()

Cordon a Node#

Cordon a Node to mark it as unschedulable.

from kr8s.objects import Node

node = Node("k8s-node-1")

node.cordon()
from kr8s.asyncio.objects import Node

node = await Node("k8s-node-1")

await node.cordon()

Pod Exec#

Exec a command in a Pod.

from kr8s.objects import Pod

pod = Pod.get("my-pod")

command = pod.exec(["uptime"])
print(command.stdout.decode())
# 13:49:05 up 23:03,  0 users,  load average: 0.66, 0.87, 0.85
from kr8s.asyncio.objects import Pod

pod = await Pod.get("my-pod")

command = await pod.exec(["uptime"])
print(command.stdout.decode())
# 13:49:05 up 23:03,  0 users,  load average: 0.66, 0.87, 0.85

Port forward a Pod#

Open a port forward to a Pod as a background task/thread.

from kr8s.objects import Pod

pod = Pod.get("my-pod")
# Listen on port 5678 on 127.0.0.1, forwarding to 5000 in the pod
pf = pod.portforward(remote_port=5000, local_port=5678)


# Starts the port forward in a background thread
pf.start()

# Your other code goes here

# Optionally stop the port forward thread (it will exit with Python anyway)
pf.stop()
from kr8s.asyncio.objects import Pod

pod = await Pod.get("my-pod")
pf = pod.portforward(remote_port=1234, local_port=5678)

# Starts the port forward in a background task
await pf.start()

# Your other code goes here
# WARNING: Your code must be async and non-blocking as the port forward and your code are sharing the same event loop

# Optionally stop the port forward task (it will exit with Python anyway)
await pf.stop()

More examples#

See the Examples Documentation for a full set of examples.