# 
[](https://jacobtomlinson.dev/effver)
[](https://pypi.org/project/kr8s/)
[](https://pypi.org/project/kr8s/)
[](https://docs.kr8s.org/en/stable/installation.html#supported-kubernetes-versions)
[](https://pypi.org/project/kr8s/)
[](https://pypi.org/project/kr8s/)
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](authentication) to reduce boiler plate.
- No swagger generated code, human readable code only.
- Has both a standard and an [async API](asyncio) that can be used with `asyncio` and `trio`.
- [Client caching](#client-caching) to reduce passing API objects around.
- Batteries included by providing [useful utilities and methods](examples/pod_operations) inspired by `kubectl`.
## Quickstart
### Installation
```console
$ pip install kr8s
```
## Examples
```{seealso}
See the [Examples Documentation](examples/index) for a full set of examples.
```
### List Nodes
Print out all of the node names in the cluster.
`````{tab-set}
````{tab-item} Sync
:sync: sync
```python
import kr8s
for node in kr8s.get("nodes"):
print(node.name)
```
````
````{tab-item} Async
:sync: async
```python
import kr8s.asyncio
for node in await kr8s.asyncio.get("nodes"):
print(node.name)
```
````
`````
### Create a Pod
Create a new Pod.
`````{tab-set}
````{tab-item} Sync
:sync: sync
```python
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()
```
````
````{tab-item} Async
:sync: async
```python
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.
`````{tab-set}
````{tab-item} Sync
:sync: sync
```python
from kr8s.objects import Deployment
deploy = Deployment.get("metrics-server", namespace="kube-system")
deploy.scale(1)
```
````
````{tab-item} Async
:sync: async
```python
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.
`````{tab-set}
````{tab-item} Sync
:sync: sync
```python
import kr8s
selector = {'component': 'kube-scheduler'}
for pod in kr8s.get("pods", namespace=kr8s.ALL, label_selector=selector):
print(pod.namespace, pod.name)
```
````
````{tab-item} Async
:sync: async
```python
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.
`````{tab-set}
````{tab-item} Sync
:sync: sync
```python
from kr8s.objects import Pod
pod = Pod("kube-apiserver", namespace="kube-system")
pod.label({"foo": "bar"})
```
````
````{tab-item} Async
:sync: async
```python
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.
`````{tab-set}
````{tab-item} Sync
:sync: sync
```python
from kr8s.objects import Pod
pod = Pod.gen(name="example-1", image="nginx:latest")
pod.create()
```
````
````{tab-item} Async
:sync: async
```python
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.
`````{tab-set}
````{tab-item} Sync
:sync: sync
```python
from kr8s.objects import Node
node = Node("k8s-node-1")
node.cordon()
```
````
````{tab-item} Async
:sync: async
```python
from kr8s.asyncio.objects import Node
node = await Node("k8s-node-1")
await node.cordon()
```
````
`````
### Pod Exec
Exec a command in a Pod.
`````{tab-set}
````{tab-item} Sync
:sync: sync
```python
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
```
````
````{tab-item} Async
:sync: async
```python
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.
`````{tab-set}
````{tab-item} Sync
:sync: sync
```python
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()
```
````
````{tab-item} Async
:sync: async
```python
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](examples/index) for a full set of examples.
```{toctree}
:maxdepth: 2
:caption: Getting Started
:hidden: true
Overview
installation
examples/index
guides/index
```
```{toctree}
:maxdepth: 2
:caption: Foundations
:hidden: true
authentication
object
client
asyncio
```
```{toctree}
:maxdepth: 2
:caption: API Reference
:hidden: true
autoapi/kr8s/index
```
```{toctree}
:maxdepth: 2
:caption: Misc
:hidden: true
alternatives
branding
history
```
```{toctree}
:maxdepth: 2
:caption: Development
:hidden: true
contributing
releasing
```