How do I run kubectl apply-f using the API

[moluzhui]

I tried using the Kubernetes API python to execute the kubect apply command to deploy and update resources

the kubectl command is as follows:

kubectl apply -f export

export is a folder containing multiple yaml files, which is generated by kompose convert -o export

I only found an alternative API for kubectl create, but I didn't find apply

How do I implement kubectl apply to create resources and possible subsequent updates

If you know, please let me know. thank you in advance!

[Sunnykaby]

maybe you can use replace_XXX api

[moshevayner]

You can look at that example as well https://github.com/kubernetes-client/python/blob/master/kubernetes/utils/create_from_yaml.py

[vishnu667]

@MoShitrit create_from_yaml works when we have to create a resource.
Let's say I want to update an annotation or the image create_from_yaml fails with a FailToCreateError

[vishnu667]

Trying to write a utility replace_from_yaml
But am hitting the error.

{
  "kind": "Status",
  "apiVersion": "v1",
  "metadata": {
    
  },
  "status": "Failure",
  "message": "the name of the object (scheduler-deployment) does not match the name on the URL (airflow)",
  "reason": "BadRequest",
  "code": 400
}

The same payload works with kubectl replace -f not sure what am missing.

[moshevayner]

Trying to write a utility replace_from_yaml
But am hitting the error.

{
  "kind": "Status",
  "apiVersion": "v1",
  "metadata": {
    
  },
  "status": "Failure",
  "message": "the name of the object (scheduler-deployment) does not match the name on the URL (airflow)",
  "reason": "BadRequest",
  "code": 400
}

The same payload works with kubectl replace -f not sure what am missing.

What's the value of kind from this line, in the error you're getting?
https://github.com/vishnu667/python/blob/replace_from_yaml/kubernetes/utils/replace_from_yaml.py#L156

[vishnu667]

This is the payload Am passing

apiVersion: apps/v1
kind: Deployment
metadata:
  annotations:
    deployment_time: '2020-05-22 12:39:38.324272'
  labels:
    app: scheduler
  name: scheduler-deployment
  namespace: airflow
spec:
  replicas: 1
  selector:
    matchLabels:
      app: scheduler
  template:
    metadata:
      annotations:
        deployment_time: '2020-05-22 12:39:38.324286'
      labels:
        app: scheduler
    spec:
      containers:
      - args:
        - scheduler
        env:
        - name: AIRFLOW__KUBERNETES__NAMESPACE
          value: airflow
        image: airflow_base:local
        imagePullPolicy: IfNotPresent
        name: scheduler
      serviceAccountName: airflow-scheduler-serviceaccount

If you can point me in the right direction I might be able to write down both these functionalities replace and apply.

[moshevayner]

The payload seems fine. But looking back at your code, I think I see what's missing.
You'll need to add a namespace argument to the call you make here https://github.com/vishnu667/python/blob/replace_from_yaml/kubernetes/utils/replace_from_yaml.py#L157
and in order to make sure you always have a value (which would align with how kubectl does it), you'll need to add an else block here like this:

else:
    namespace = "default"

namespace is a required parameter, and by the error message it seems like the function is trying to use airflow as the name of the deployment, rather than the namespace.
So I would try to be more explicit and see if it helps.

[roycaihw]

kubectl implements a three-way diff logic to perform a client-side apply. We should add example/documentation about how to use the new server-side apply feature instead of re-implementing client-side apply in this client.

[vishnu667]

@roycaihw Can you point me to the kubectl implementation Let me see if I can code the same logic in python.

[vishnu667]

@MoShitrit agree but for the yaml am providing am passing the namespace value.
Will add the else statement also.

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[solarmosaic-kflorence]

I'm not sure how people are using the python client without this feature... I'm trying to move our deployment process from command line tools (like kubectl) into a python lambda function and I'm surprised to find there is no easy way to replace a kubectl apply -f with a client call.

[solarmosaic-kflorence]

@tvkit i'm sure it is, but it doesn't have a lot to do with the apply functionality that kubectl provides. And I'd rather not use python just to call a CLI command... kind of defeats the purpose of using python.

[solarmosaic-kflorence]

This ticket may be a duplicate of #1093

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[adammrozik]

Hey! Is there any chance this would be implemented in the future?

Not sure how to effectively mimic kubectl apply behaviour with current API

[robcxyz]

@adammrozik - Looks like they just merged an example https://github.com/kubernetes-client/python/pull/1752/files

[Sispheor]

@adammrozik - Looks like they just merged an example https://github.com/kubernetes-client/python/pull/1752/files

This example actually uses the create_from_directory method. Which does not perform an "apply" and return "Error from server (Conflict)" if objects exists already...

[Pithikos]

I assume this requires a rewrite of kubectl's apply in Python.

The workaround is to pipe input to kubectl

subprocess.run(["kubectl", "apply", "-f", "-"], input=substituted, encoding='utf-8')

Where input is just the parsed YAML as a string