Receive data from Kubernetes API using curl

Start by running kubectl’s proxy. With its help, we avoid dealing with authentication headers.

kubectl proxy

Test the connection with a basic call.

curl http://localhost:8001/api/

To check the API groups available, access the root.

curl http://localhost:8001/apis/

Based on the group listing, you can infer URLs for resources.

For cluster-scoped resources, use:

/apis/<GROUP>/<VERSION>/<RESOURCETYPE>
/apis/<GROUP>/<VERSION>/<RESOURCETYPE>/<NAME>

And, for namespace-scoped resources:

/apis/<GROUP>/<VERSION>/<RESOURCETYPE>
/apis/<GROUP>/<VERSION>/namespaces/<NAMESPACE>/<RESOURCETYPE>
/apis/<GROUP>/<VERSION>/namespaces/<NAMESPACE>/<RESOURCETYPE>/<NAME>

To get deployment data, for example, the API Group is “apps”, Version is “v1” and Resourcetype is “deployments”. The final request looks like this:

curl http://localhost:8001/apis/apps/v1/deployments

If your Kubernetes cluster has a metrics-server, the following request will get node resource usage data:

curl http://localhost:8001/apis/metrics.k8s.io/v1beta1/nodes

Rancher users

However, if your cluster was created using Rancher, you’ll need “Authorized Cluster Endpoint” enabled, so your requests can reach the API Server directly. Your URL paths will slightly differ from the examples above otherwise.

Using your command line, you’ll also need to select the correct context for kubectl before activating the proxy.

# List available contexts
kubectl config get-contexts

# Select the direct API context
# Its name has the format <cluster_name>-<pilot_name>
kubectl config use-context <direct_context>

Further reading

Overview of the Kubernetes API

More info about API concepts

Accessing the API without kubectl proxy

Full list of Groups, Versions and Resourcetypes