kubernetes-py

Kubernetes API bindings in Python.

Run on our own on-prem and AWS Kubernetes clusters at 1.5.6

Also unit tested on Google GKE clusters at 1.6.4

Currently supported Kubernetes objects:

~/.kube/config
ComponentStatus
Container
CronJob
DaemonSet
Deployment
HorizontalPodAutoscalers
Job
Namespace
Node
PersistentVolume
PersistentVolumeClaim
PetSet
Pod
ReplicaSet
ReplicationController
Secret
Service
ServiceAccount
StatefulSet
StorageClass
Volume
VolumeMount

Usage

Find some code snippets below to help understand how to use this module.

Configuration

By default, the module attempts to load existing configuration from ~/.kube/config. You are welcome to specify another location if you so choose.

Otherwise, individual configuration parameters can be overridden piecemeal. In this case you must specify kubeconfig=None when initializing a K8sConfig object; the ~/kube/.config file takes precedence if it exists.

from kubernetes import K8sConfig

# Defaults found in ~/.kube/config
cfg_default = K8sConfig()

# Defaults found in another kubeconfig file
cfg_other = K8sConfig(kubeconfig='/path/to/kubeconfig')

# Overriding the host, using basic auth
cfg_basic = K8sConfig(
    kubeconfig=None, 
    api_host=somehost:8888, 
    auth=('basic_user', 'basic_passwd')
)

# Overriding the host, using certificates
cfg_cert = K8sConfig(
    kubeconfig=None, 
    api_host=somehost:8888, 
    cert=('/path/to/cert.crt', '/path/to/cert.key')
)

# Overriding the host, using a Bearer token
cfg_token = K8sConfig(
    kubeconfig=None, 
    api_host=somehost:8888, 
    token='50a2fabfdd276f573ff97ace8b11c5f4'
)

Containers

This module assumes the default container runtime.

Defining a container:

from kubernetes import K8sContainer

container = K8sContainer(name='redis', image='redis:3.0.7')
container.add_port(
    container_port=6379, 
    host_port=6379, 
    name='redis'
)

CronJobs

Creating a CronJob

from kubernetes import K8sCronJob

cj = K8sCronJob(
    config=cfg_cert,
    name='my-cronjob',
)
cj.schedule = '*/1 * * * *'
cj.concurrency_policy = 'Forbid'
cj.starting_deadline_seconds = 10
cj.create()

Updating a CronJob

from kubernetes import K8sCronJob

cj = K8sCronJob(config=cfg_cert, name='my-cronjob').get()
cj.suspend = True
cj.update()

Deleting a CronJob

from kubernetes import K8sCronJob

cj = K8sCronJob(config=cfg_cert, name='my-cronjob').get()
cj.delete()

Deployments

Creating a Deployment:

from kubernetes import K8sDeployment

deployment = K8sDeployment(
    config=cfg_cert, 
    name='my-deployment',
    replicas=3
)
deployment.add_container(container)
deployment.create()

Fetching a Deployment:

from kubernetes import K8sDeployment

deployment = K8sDeployment(config=cfg_cert, name='my-deployment')
deployment.get()

Fetching all available Deployments:

from kubernetes import K8sDeployment

deployment = K8sDeployment(config=cfg_cert, name='my-deployment')
deployment.list()

Updating a Deployment:

from kubernetes import K8sDeployment, K8sContainer

deployment = K8sDeployment(config=cfg_cert, name='my-deployment')
container = K8sContainer(name='nginx', image='nginx:1.7.9')
deployment.add_container(container)
deployment.create()
deployment.set_container_image(name='nginx', image='nginx:1.9.1')
deployment.update()

Scaling a Deployment:

from kubernetes import K8sDeployment, K8sContainer

deployment = K8sDeployment(config=cfg_cert, name='my-deployment')
container = K8sContainer(name='nginx', image='nginx:1.7.9')
deployment.add_container(container)
deployment.set_replicas(3)
deployment.create()
deployment.scale(10)

Deleting a Deployment:

from kubernetes import K8sDeployment

deployment = K8sDeployment(config=cfg_cert, name='my-deployment')
deployment.delete()

Jobs

Creating a Job

from kubernetes import K8sJob

job = K8sJob(config=cfg_cert, name='my-job')
job.parallelism = 10
job.completions = 20
job.create()

Updating a Job

from kubernetes import K8sJob

job = K8sJob(config=cfg_cert, name='my-job').get()
job.parallelism = 5
job.update()

Deleting a Job

from kubernetes import K8sJob

job = K8sJob(config=cfg_cert, name='my-job').get()
job.delete()

Persistent Volumes

Creating an AWS EBS Persistent Volume:

from kubernetes import K8sPersistentVolume

pv_aws = K8sPersistentVolume(
    config=cfg_cert, 
    name="my-aws_ebs", 
    type="awsElasticBlockStore"
)
pv_aws.fs_type = "xfs"
pv_aws.volume_id = "vol-0a89cd040d534a371"
pv_aws.create()

As specified:

the nodes on which pods are running must be AWS EC2 instances
those instances need to be in the same region and availability-zone as the EBS volume
EBS only supports a single EC2 instance mounting a volume

Pod creation will timeout waiting for readiness if not on AWS; unschedulable.

Creating a GCE PD Persistent Volume

from kubernetes import K8sPersistentVolume

pv_gce = K8sPersistentVolume(
    config=cfg_cert, 
    name="my-gce_pd", 
    type="gcePersistentDisk"
)
pv_gce.fs_type = "ext4"
pv_gce.pd_name = "han-shot-first"
pv_gce.create()

As specified:

the nodes on which pods are running must be GCE VMs
those VMs need to be in the same GCE project and zone as the PD

Pod creation will timeout waiting for readiness if not on GCE; unschedulable.

Creating an NFS Persistent Volume

from kubernetes import K8sPersistentVolume

pv = K8sPersistentVolume(
    config=cfg_cert,
    name="my-pv",
    type="nfs"
)
pv.nfs_server = "nfs.mycompany.com"
pv.nfs_path = "/path/to/dir"
pv.create()

Persistent Volume Claims

Creating and Mounting a PersistentVolumeClaim

from kubernetes import K8sContainer
from kubernetes import K8sPersistentVolumeClaim
from kubernetes import K8sPod
from kubernetes import K8sVolume
from kubernetes import K8sVolumeMount

container = K8sContainer(name='nginx', image='nginx:1.9.1')

pvc = K8sPersistentVolumeClaim(
    config=cfg_cert,
    name="my-pvc",
)
pvc.create()

vol = K8sVolume(
    config=cfg_cert,
    name="my-volume",
    type="persistentVolumeClaim"
)
vol.claim_name = pvc.name

mount = K8sVolumeMount(
    config=cfg_cert,
    name=vol.name,
    mount_path="/path/on/container"
)
container.add_volume_mount(mount)

pod = K8sPod(
    config=cfg_cert,
    name="my-pod"
)
pod.add_volume(vol)
pod.add_container(container)
pod.create()

Pods

Creating a Pod:

from kubernetes import K8sPod

pod = K8sPod(config=cfg_basic, name='redis')
pod.add_container(container)
pod.create()

Fetching a Pod:

from kubernetes import K8sPod

pod = K8sPod(config=cfg_token, name='redis')
pod.get()

Fetching all available Pods:

from kubernetes import K8sPod

pod = K8sPod(config=cfg_token, name='redis')
pod.list()

Deleting a Pod:

from kubernetes import K8sPod

pod = K8sPod(config=cfg_cert, name='redis')
pod.delete()

ReplicationController

Creating a ReplicationController:

from kubernetes import K8sReplicationController

rc = K8sReplicationController(
    config=cfg_cert, 
    name='redis', 
    image='redis:3.2.3', 
    replicas=1
)
rc.create()

Fetching a ReplicationController:

from kubernetes import K8sReplicationController

rc = K8sReplicationController(config=cfg_cert, name='redis')
rc.get()

Fetching all available ReplicationControllers:

from kubernetes import K8sReplicationController

rc = K8sReplicationController(config=cfg_cert, name='redis')
rc.list()

Deleting a ReplicationController:

from kubernetes import K8sReplicationController

rc = K8sReplicationController(config=cfg_cert, name='redis')
rc.delete()

Service

Creating a service:

from kubernetes import K8sService

svc = K8sService(config=cfg_cert, name='redis')
svc.add_port(name='redisport', port=31010, target_port='redisport')
svc.add_selector(selector=dict(name='redis'))
svc.set_cluster_ip('192.168.1.100')
svc.create()

Fetching a service:

from kubernetes import K8sService

svc = K8sService(config=cfg_cert, name='redis')
svc.get()

Deleting a service:

from kubernetes import K8sService

svc = K8sService(config=cfg_cert, name='redis')
svc.delete()

Secret

Creating a secret:

from kubernetes import K8sSecret

data = { "auths": {
            "repo:port": {
                "auth": "authstring", 
                "email": "[email protected]"
            }}}  

secret = K8sSecret(config=cfg_cert, name='my-registry')
secret.dockerconfigjson = data
secret.create()

Fetching a secret:

from kubernetes import K8sSecret

secret = K8sSecret(config=cfg_cert, name='my-registry')
secret.get()

Deleting a secret:

from kubernetes import K8sSecret

secret = K8sSecret(config=cfg_cert, name='my-registry')
secret.delete()

Volume

Mounting an AWS EBS volume inside a Pod:

from kubernetes import K8sVolume

volume = K8sVolume(
    config=cfg_cert,
    name='aws-volume',
    type='awsElasticBlockStore',
    mount_path='/path/inside/container'
)
volume.set_volume_id('vol-123456')  # this volume must already exist
container.add_volume_mount(volume)
pod.add_volume(volume)
pod.add_container(container)
pod.create()

Unit tests

The unit tests that require making remote API calls check if there is a reachable API server; if no such endpoint is found, the test is skipped.

It is recommended to begin testing things out against minikube. However, be aware that minikube does not support the entire feature set of a full Kubernetes install.

$ nosetests --with-coverage --cover-package=kubernetes

Please note that when using minikube, and Kubernetes in general, the default hosts are as below:

kubernetes
kubernetes.default
kubernetes.default.svc
kubernetes.default.svc.cluster.local

For certificate validation to succeed, you should edit your ~/.kube/config to address one of the hosts, eg.:

- cluster:
    certificate-authority: /Users/kubernetes/.minikube/ca.crt
    server: https://kubernetes:8443

Finally, add an entry to your /etc/hosts file for the host alias you choose.

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