Kubernetes client-python creating a service error

Question

I am trying to create a new service for one of my deployments named node-js-deployment in GCE hostes Kubernetes Cluster

I followed the Documentation to create_namespaced_service

This is the service data:

{
    "kind": "Service",
    "apiVersion": "v1",
    "metadata": {
        "name": "node-js-service"
    },
    "spec": {
        "selector": {
            "app": "node-js"
        },
        "ports": [
            {
                "protocol": "TCP",
                "port": 80,
                "targetPort": 8000
            }
        ]
    }
}

This is the Python function to create the service

api_instance = kubernetes.client.CoreV1Api()
namespace = 'default'  

body = kubernetes.client.V1Service()  # V1Serice

# Creating Meta Data
metadata = kubernetes.client.V1ObjectMeta()
metadata.name = "node-js-service"

# Creating spec 
spec = kubernetes.client.V1ServiceSpec()

# Creating Port object
ports = kubernetes.client.V1ServicePort()
ports.protocol = 'TCP'
ports.target_port = 8000
ports.port = 80

spec.ports = ports
spec.selector = {"app": "node-js"}

body.spec = spec


try:
    api_response = api_instance.create_namespaced_service(namespace, body, pretty=pretty)
    pprint(api_response)
except ApiException as e:
    print("Exception when calling CoreV1Api->create_namespaced_service: %s\n" % e)

Error:

Reason: Bad Request
HTTP response headers: HTTPHeaderDict({'Content-Type': 'application/json', 'Date': 'Tue, 21 Feb 2017 03:54:55 GMT', 'Content-Length': '227'})
HTTP response body: {"kind":"Status","apiVersion":"v1","metadata":{},"status":"Failure","message":"Service in version \"v1\" cannot be handled as a Service: only encoded map or array can be decoded into a struct","reason":"BadRequest","code":400}

But the service is being created if I am passing JSON. Not sure what I am doing wrong.

Any help is greatly appreciated, thank you.

Never used client-python and thus can't help 100%. But I'd guess you at least forgot to assign the metadata object to body.metadata. Also, ports should have been an array with 1 element. — Alexander Block
– Alexander Block, Commented Feb 22, 2017 at 20:47
I missed to include the metadata in the question. In my code I actually did. May be it was about how I was trying to attach the ports. But finally ended up using dictionaries for deployment and services. It was simple and easy. — kt14
– kt14, Commented Feb 24, 2017 at 12:25

fersarr · Accepted Answer · 2019-12-04 15:22:19Z

7

From reading your code, it seems that you miss assigning the metadata to body.metadata. And you missed that the ports field of the V1ServiceSpec is supposed to be a list, but you used a single V1ServicePort so without testing I assume this should works:

api_instance = kubernetes.client.CoreV1Api()
namespace = 'default'

body = kubernetes.client.V1Service()  # V1Serice

# Creating Meta Data
metadata = kubernetes.client.V1ObjectMeta()
metadata.name = "node-js-service"

body.metadata = metadata

# Creating spec
spec = kubernetes.client.V1ServiceSpec()

# Creating Port object
port = kubernetes.client.V1ServicePort()
port.protocol = 'TCP'
port.target_port = 8000
port.port = 80

spec.ports = [ port ]
spec.selector = {"app": "node-js"}

body.spec = spec

The definition could also be loaded from json / yaml directly as shown in two of the examples within the offical repo - see exec.py create_deployment.py.

Your solution could then look like:

api_instance = kubernetes.client.CoreV1Api()
namespace = 'default'

manifest = {
    "kind": "Service",
    "apiVersion": "v1",
    "metadata": {
        "name": "node-js-service"
    },
    "spec": {
        "selector": {
            "app": "node-js"
        },
        "ports": [
            {
                "protocol": "TCP",
                "port": 80,
                "targetPort": 8000
            }
        ]
    }
}

try:
    api_response = api_instance.create_namespaced_service(namespace, manifest, pretty='true')
    pprint(api_response)
except ApiException as e:
    print("Exception when calling CoreV1Api->create_namespaced_endpoints: %s\n" % e)

edited Dec 4, 2019 at 15:22

fersarr

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answered Feb 22, 2017 at 21:15

pagid

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1 Comment

kt14 Over a year ago

passing the yaml as dictionary works perfectly, I have added the metadata to the body in my code bu failed to update it in the question. But like you said the problem might be on how I am passing the Ports not as a list.

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