Introduction

To make a pod with kubernetes, you can first create a yaml file of the pod and then apply the created yaml file with a command, but I want to create a pod from python code without using a command. When I looked it up, I couldn't find the article, and I had a hard time writing the program, so I'll share it.

environment

Ubuntu 18.04.2 LTS
python 3.6.9
Environment where kubernetes works

Basic method of creating a pod

First, try to create a basic pod. Any yaml file to create a pod is fine, but for the time being, create a simple pod.yaml file.

$ vim pod.yaml

It's easy to copy and paste with: set paste

`pod.yaml`


#Rules for writing pods
apiVersion: v1
kind: Pod
#Detailed information such as pod name and label
metadata:
  name: myapp-pod  #Give the pod a name
  labels:
    app: myapp  #Label app->Add myapp
#Information of the container body to be placed in the pod
spec:
  containers:
    - name: demo-container  #Give the container a name
      image: nginx  #Container name(Matches the name of Docker Hub)
      ports:
        - containerPort: 80  #Use port 80

Apply pod.yaml to create a pod.

$ kubectl apply -f pod.yaml
pod/myapp-pod created

Check if the pod is made.

$ kubectl get pod
NAME        READY   STATUS    RESTARTS   AGE
myapp-pod   1/1     Running   0          34s

The pod I made is used up, so delete it.

$ kubectl delete -f pod.yaml
pod "myapp-pod" deleted
$ kubectl get pod
No resources found in c0118272 namespace.

Created from python

Install what you need.

$ pip3 install flask
$ pip3 install kubernetes

Create a python program that creates a pod with the name podcreate.py in the same directory as pod.yaml. Change namespace to your own namespace name. The basic is default.

$ vim podcreate.py

`podcreate.py`


from flask import Flask
from flask import request
from kubernetes import client, config, watch
import yaml

app = Flask(__name__)
@app.route('/')
def pod_create():
    config.load_kube_config()
    with open("pod.yaml", "r") as f:
        pod = yaml.safe_load(f)
        k8s_apps_v1 = client.CoreV1Api()
        resp = k8s_apps_v1.create_namespaced_pod(body=pod, namespace="c0118272")
        print("pod created. status='%s'" % resp.metadata.name)
    return "pod created. status='%s'" % resp.metadata.name

if __name__ == "__main__":
    app.run(host='0.0.0.0', port=80)

Check the positional relationship of the files.

$ ls
podcreate.py  pod.yaml

Since I wrote it in flask, I will display it on the browser and execute it.

$ export FLASK_APP=podcreate.py
$ flask run --host=0.0.0.0
 * Serving Flask app "podcreate.py"
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: off
 * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
 *

Try running it in your browser. If the url is local, it is http://0.0.0.0:5000. If it is not local, the port is 5000 and the IP address is different for each execution environment.

If it looks like the image above, you're successful!

Check with the command.

$ kubectl get pod
NAME        READY   STATUS    RESTARTS   AGE
myapp-pod   1/1     Running   0          3m11s

Once you have a pod, you're done! !!

in conclusion

I'm using the kubernetes api, but it's difficult and I'm not sure, so please check each application method! Have a good research life ~

How to create a kubernetes pod from python code